EP2648178B1 - Assembly for emitting light with a flat light conducting element - Google Patents

Description

The present invention relates to a light-guiding element for use in a light-emitting device according to the preamble of claim 1, in which light is coupled in at the front end and emitted via a flat side separated from the end face. In particular, the present invention relates to a escape sign light for indicating escape routes or the like.

The use of light-guiding elements for surface light emission has long been known in lighting technology. The basic principle of such elements is based on the fact that light from one or more light sources is irradiated via a narrow side into the element consisting of a transparent material. Reflections propagate the light within the light guide element and distribute it essentially over the entire element. By means of special so-called light extraction structures, a portion of the light is then emitted in each case via a flat side oriented essentially perpendicular to the light coupling surface. The advantage of using such light-guiding elements is that the light provided by the light sources can be emitted uniformly over a relatively large area, and nevertheless a compact arrangement is achieved. In contrast, lighting arrangements in which a surface light output is to be achieved by means of reflectors or the like, a significantly higher design.

A special field of application for such arrangements for the emission of light are so-called escape route luminaires. These are lights that serve to make a pictogram or the like appear bright to indicate to people within a building an escape route that allows easy and quick exit from the building. Whereas in the past the pictograms had to be backlit by a flat arrangement of light sources, a much more compact arrangement can now be achieved when using the above-described light control technique, since the light source or light sources need only be located on a specific side of the luminaire. In spite of everything, it is ensured with the help of the light element that the pictogram is uniformly backlit across its entire surface and, accordingly, is clearly visible. Furthermore, the pictogram can already be applied directly to the flat side of the light-guiding element used as the light-emitting surface, for example printed, so that a luminaire consisting of very few elements can be realized.

Originally, in lighting arrangements in which light-guiding elements of the type described above were used, elongated light sources, in particular in the form of fluorescent lamps or the like, were used to couple light into the light-conducting element on the face side. In the meantime, dot-shaped light sources, for example LEDs or organic LEDs (so-called OLEDs), which are then arranged next to each other and aligned with the light-incoupling surface of the light-guiding element, are increasingly used. LEDs have the advantage that they work more energy efficient compared to conventional light sources and generally also have a higher reliability.

On the other hand, LEDs must also be more elaborately protected from external influences and care must be taken in particular that the LEDs or the board, which serves as a carrier for the LEDs, is not inadvertently touched by a consumer or user This may lead to so-called ESD damage due to possible electrostatic discharges. The penetration of moisture or the like is very problematic in this case. In this context, although it is known to form to optimize the light coupling in the LED facing the end face of a light guide wells into which the LEDs partially protrude, however, even with this solution, no satisfactory protection of the LEDs or the LED board from the outside Ensures influences and it must be taken extra costly measures to ensure the necessary protection. This is especially the case when an application of the lighting arrangement is planned in areas in which a higher humidity is present.

From the DE 101 23 006 A1 , of the DE 199 45 495 A1 and the DE 295 12 090 U1 are light-guiding elements, which are sometimes used as emergency sign or emergency application, both of which a light coupling takes place at different points of the light-guiding elements.

The present invention is now based on the object to provide a solution in which a reliable protection of the light sources from external influences is ensured when using a planar light guide. In particular, the arrangement should be suitable to be used in areas with higher humidity, in spite of all no damage to the components of the lighting arrangement is to be feared.

This object is achieved by a light-guiding element for use in a light-emitting device having the features of claim 1. Advantageous developments of the invention are the subject of the dependent claims.

In the solution according to the invention, it is provided that the light sources, which are present in particular in the form of punctiform light sources, preferably LEDs, are recessed together with a corresponding carrier element for the light sources or sunk in the light guiding element. For this purpose, this has at its the Lichteinkoppelbereich forming narrow side a recess, which allows the recording of the light sources together with its support member and circumferentially bounded by the light guide. Because the components to be protected are completely accommodated in a corresponding pocket or recess, they can be protected from external influences by simple means. Thus, the remaining opening to the outside through simple measures, which will be described in more detail below, seal.

According to the invention, therefore, a light-guiding element is proposed for use in an arrangement for emitting light with a plurality of substantially point-shaped light sources, in particular LEDs, wherein the light sources are arranged on at least one narrow light side forming a light coupling region of the light guide element and the light guide element is designed to emit the light emitted by the light sources and to emit light irradiated via the light coupling region via a flat side arranged substantially perpendicular to the narrow side. According to the invention, it is provided that the light-guiding element has a recess on the narrow side forming the coupling-in area, which is designed to receive the light sources together with a carrier element for the light sources and is circumscribed by the light-guiding element.

Advantageously, an arrangement for emitting light with a planar light guide according to claim 1 and a plurality of substantially point-shaped light sources, which are arranged together with a support member for the light sources in the recess of the light guide provided.

Preferably, the light-guiding element has ribs or projections within the recess, which form contact areas for the carrier element for the light sources. If, for example, according to a preferred embodiment, an elongate LED board is used, it rests on these ribs or projections, with the result that the LEDs are arranged in a defined position with respect to the actual light coupling surface of the light-guiding element.

In particular, they have a smaller distance from this surface, which ensures efficient and optimal light coupling. In addition, these support areas also prevent twisting or tilting of the support element.

The holder or fixing of the carrier element within the recess of the light-guiding element is preferably carried out with the aid of one or more clamping elements. These can be latched, for example, in a preferred embodiment, within the recesses of the light guide and then press from the side facing away from the LEDs against the board and lock them reliably within the recess. In this case, the clamping elements may additionally comprise means for attaching suspension elements for the arrangement, said means preferably by a Strain relief of the respective suspension element is achieved. This also opens the possibility in particular to use the supply lines for the power supply of the LEDs themselves for suspending the arrangement, which additionally contributes to a very simple embodiment of the arrangement according to the invention.

A particularly reliable protection of the light sources from external influences is achieved according to the present invention in particular when the recess for receiving the light sources together with its carrier element is filled with a casting or filling compound. After arranging the board and fixing with the aid of the clamping elements in the recess of the light guide so the remaining cavity of the light guide can be filled so that a complete seal against external influences is achieved. In this case, although a later replacement of the LED board is then no longer or only very difficult to implement, but due to the longevity of the LED light sources, this should not be a major problem.

As already mentioned, the light-guiding element has a planar design, although this is not only to be understood as meaning that it has two flat sides aligned parallel to one another. The intended for the light output flat sides could for example also be wedge-shaped or the like. Even a slightly curved or curved surface would be conceivable. Preferably, the arrangement according to the invention is part of a escape sign luminaire, wherein in particular the light-guiding element simultaneously serves as a support for a pictogram to be illuminated.

Figur 1

eine Rettungszeichenleuchte mit einer erfindungsgemäß ausgebildeten Anordnung zur Lichtabgabe;

Figuren 2 bis 4

unterschiedliche Ansichten eines erfindungsgemäßen Lichtleitelements;

Figuren 5 und 6

Ansichten eines zum Fixieren des Trägerelements für die Lichtquellen in dem Lichtleitelement genutzten Klemmelements;

Figur 7

eine vergrößerte Ansicht einer sog. Kaschierhülse zum oberen Abdecken des Zuführungsbereichs für ein Abhängungselement;

Figur 8

die erfindungsgemäße Rettungszeichenleuchte in Explosionsdarstellung;

Figur 9

eine vergrößerte Ansicht der Anordnung des Trägerelements für die Lichtquellen in der Ausnehmung des Lichtleitelements und

Figur 10

eine Schnittdarstellung der erfindungsgemäßen Rettungszeichenleuchte.

The invention will be explained in more detail with reference to the accompanying drawings. Show it:

FIG. 1

a rescue sign lamp with an inventively designed arrangement for light output;

FIGS. 2 to 4

different views of a light guide according to the invention;

FIGS. 5 and 6

Views of a clamping element used for fixing the support element for the light sources in the light guide element;

FIG. 7

an enlarged view of a so-called Kaschierhülse for top covering the supply area for a suspension element;

FIG. 8

the escape sign light according to the invention in an exploded view;

FIG. 9

an enlarged view of the arrangement of the support member for the light sources in the recess of the light guide and

FIG. 10

a sectional view of the escape sign lamp according to the invention.

As a preferred embodiment of the present invention, a escape sign is described below. However, the inventive concept is by no means limited to such types of luminaires but can basically be used when a light output is to take place with the aid of light-guiding elements. In particular, in this case the light sources can also be arranged on a plurality of narrow sides of the light-guiding element in accordance with the solution according to the invention and a light output can take place via one or both flat sides of the light-guiding element.

In the FIG. 1 shown in perspective view and generally provided with the reference numeral 1 escape sign light is provided for wire suspension and is accordingly attached via two wires 50 to a support, not shown, for example, the ceiling of a room or the like. Within the lamp 1, a plurality of light sources in the form of LEDs are arranged, which are arranged side by side on an elongated board. The light of the LEDs is radiated from the top into a wedge-like design in cross-section 10. By reflection effects, the light is forwarded according to the arrow shown within the light guide 10. On its surface or the two opposite flat sides 11 and 12, the light guide 10 in a known manner structures over which incident light beams are deflected such that they leave the light guide 10 via one of these two sides 11, 12. Such a technique is already well known in transparent light-guiding elements. In the present case of use in a escape sign 1, the surface of the light guide 10 is additionally printed with a pictogram 2, via which the direction of an escape route is displayed.

The solution according to the invention is concerned in particular with the problem of the reliable arrangement of the light sources in the region of the light coupling of the light-guiding element 10, the light sources being protected against external influences should. This means, on the one hand, that accidental touching of the LEDs or of the printed circuit board with the LEDs is to be avoided, in order to avoid damage due to electrostatic discharges. On the other hand, the LEDs should also be protected from other external influences, in particular from the penetration of dust and / or moisture. In the luminaire 1 according to the invention special measures are provided for this purpose, which are described in more detail below.

The basic idea of the solution according to the invention is to embed the board with the LEDs in the light-guiding element 10 in the region of the light coupling and thereby to protect it against external influences. At the same time a reliable and effective coupling of the light is to be made possible in the light guide 10 still.

A first measure required for this purpose consists in a special embodiment of the light-guiding element 10, which is described below with reference to FIG FIGS. 2 to 4 should be explained. These figures show the light guide 10 in three different views.

The peculiarity of the light-guiding element 10 consists in particular in that the light coupling-in area 13 is provided with a recess 20, in which sunk the LED board is later added. This recess 20 or recess is bounded in the case shown circumferentially by the light guide 10, has an elongated shape and preferably extends substantially over the entire length of the light guide 10 in order also over the entire length of time Lichteinkopplung and thus uniform illumination of the To enable pictogram 2.

The bottom surface 21 of the recess 20 (see FIG. 8 ) then forms accordingly the actual light entry surface for the light guide 10. The board 30 with the LEDs 31 (see FIG. 10 ) is preferably not on the entire surface on this light entry surface 21. Instead, 21 spacers 22 are provided in the form of ribs or projections in the region of the bottom surface, on which the circuit board 30 rests. On the one hand, these spacers 22 ensure that the LEDs 31 are arranged at a defined distance from the light entry surface 21 and, accordingly, can effectively radiate the light into the light guide element 10, on the other hand, a secure mounting of the circuit board 30 is made possible without twisting or a Tilting is to be feared.

Another special feature of the recess 20 is also that it is formed on its two side areas or side walls for special support of a clamping element, which is closer in the FIGS. 5 and 6 is shown and provided with the reference numeral 35. The task of this clamping element 35 is to fix the LED board 30 in an inserted into the recess 20 position. Furthermore, these clamping elements 35 are also the suspension of the lamp 1, as will be described in more detail below.

The clamping elements 35 initially have a plate-like region 36, from which a downwardly bent tongue 37 is punched out. At one end of the plate-like portion 36, an upwardly directed web 38 is further formed, which is provided on the one hand at its two longitudinal sides with a toothing 39 and on the other hand has two holes 40. The function of the toothing 39 and the holes 40 will be explained in more detail below.

As in particular the representation of FIG. 2 can be removed, the recess 20 of the light guide 10 in the side walls on two guide or receiving portions 25 for the storage of the clamping elements 35. These guide portions 25 are each formed on the two opposite side walls by a guide slot or a groove 26, in which the clamping element 35 is inserted laterally. For this purpose, the recess 20 is formed slightly enlarged adjacent to the guide portion 25 so that from the open side, the clamping member 35 can first be inserted from above and then laterally displaced until it fully engages the plate-like portion 36 in the two guide slots 26. A respectively formed at the beginning of the guide slot 26 and downwardly projecting projection 27 in this case ensures a fixation of the clamping member 35 in the longitudinal direction, so that it can no longer escape from the inserted position. At the same time presses in this state then the clamping element 35 with the downwardly bent tongue 37 against the upper side of the LED board 30 and fixes them in this way in the inserted into the recess 20 position. Due to this pressing force of the tongue 37, the clamping element 35 is pressed upward and accordingly fixed behind the downwardly projecting locking lug or the projection 27 of the guide portion 25.

The installation of the escape sign 1 is carried out according to the representation of FIG. 8 then by first of all the board 30 populated with the LEDs 31 being inserted into the recess 20 of the light-guiding element 10. In this state, the board 30 is already soldered to the two connection cables or wire ropes 50, which on the one hand the power supply and on the other hand, the suspension of the lamp. 1 serve. After inserting the board 30 into the recess 20, the two clamping elements 35 are then inserted in the manner described above and moved in the transverse direction, so that they engage in the guide portions 25. The two cables 50 are then passed under each of the clamping elements 35 and then threaded through the two openings 40 of the web 38, so that the in FIG. 9 shown arrangement results. In this way, with the help of the clamping elements 35 and a strain relief is realized, which allows a suspension of the lamp 1 to the lines for power supply, without affecting the connection to the LED board 30 is affected.

In this state, the LED board 30 is reliably fixed in the recess 20 of the light-guiding element 10. In order to enable a complete seal against external influences is now provided to fill the remaining space of the recess 20 with a filling or potting material. In this case, the use of a transparent, polyurethane-type potting compound is particularly suitable. This thus fills the remaining areas of the recess 20, in particular the above the board 30 lying areas such that a complete seal against the environment is achieved and, accordingly, a so-called. Protection can be achieved according to IP 42 or even higher. Since in the filling of the recess 20 with the potting compound possibly formed air pockets could affect the light input into the light guide 10 massively, the recess 20 seen over its longitudinal direction is provided with several spacers 28 (see FIG. 2 ). These widenings 28 not only serve to allow the insertion of the clamping elements 35 in the procedure described above, but also allow the air to escape laterally during pouring of the potting compound. Ultimately, therefore, the recess 20 is actually completely filled, so even below the board 30 through the potting compound and the LED board is completely encased and effectively protected from external influences. The light coupling into the light guide 10 is not affected despite everything.

After the casting or filling of the recess 20, a cover plate 60, preferably made of aluminum, is then placed from the upper side, which has two openings 61 for the passage of the suspension cables 50. With the help of two Kaschierhülsen 65, which in average in FIG. 7 The Kaschierhülsen 65 serve primarily optical purposes and have an internal thread 66, which screwing the sleeve 65 with the upwardly projecting beyond the potting compound web 38th of Clamping elements 35 allows. By means of a centering ring 67 located at the lower end of the laminating sleeve 65, a correct centered seat of the cover plate 60 is made possible.

In the end, the result is the in FIG. 1 in perspective view as well as in FIG. 10 shown in cross-sectional configuration of the escape sign light according to the invention, in which the light emitted by the LEDs 31 light is effectively coupled into the light guide 10 and at the same time a reliable protection of the LED board 30 is guaranteed against external influences.

As already mentioned, the invention is not limited to escape sign luminaires. Furthermore, the light-guiding element can also be designed otherwise with regard to the alignment and configuration of the surfaces for emitting light.

Claims (10)

1. Arrangement for light output with a planar light guiding element (10) with a plurality of substantially point-like light sources (31), which are arranged on at least one narrow side that forms a light input coupling section (13) of a light guide (10), wherein the light guiding element (10) is designed to reflect the light emitted by the light sources (31) and irradiated via the light input coupling section (13) via a flat side (11, 12) arranged
   substantially vertically to the narrow side,
   characterised in that
   the light guiding element (10) has a recess (20) on the narrow side that forms the light input coupling section (13), which is arranged to accommodate the light sources (31) together with a support element (30) and is peripherally delimited by the light guiding element (10).
2. Arrangement for light output with a planar light guiding element (10) according to claim 1 as well as multiple substantially point-like light sources (31), which are arranged in the recess (20) of the light-guiding element (10), together with a support element (30) for the light sources (31).
3. Arrangement for light output according to claim 2,
   characterised in that
   the light guiding element (10) has ribs (22) or projections (22) in the recess (20), in particular on a bottom surface (21), which constitute bearing portions for the support element (30) of the light sources (31).
4. Arrangement according to claim 2 or 3,
   characterised in that
   the support element (30) for the light sources (31) is fixed by means of one or more clamping elements (35) in the recess (20).
5. Arrangement according to claim 4,
   characterised in that
   the recess (20) has on its side walls means for locking or fixing the clamping element (35).
6. Arrangement according to claim 4 or 5,
   characterised in that
   the one or more clamping elements (35) have means for fastening suspension elements (50) for the arrangement.
7. Arrangement according to claim 6,
   characterised in that
   the one or more clamping elements (35) have a web (38) projecting from the recess (20), comprising openings (40) for implementing a cable-like suspension member (50) and the strain relief of such.
8. Arrangement according to one of the claims 2-7,
   characterised in that
   the recess (20) is filled with a potting or filling compound.
9. Arrangement according to one of the claims 2-8,
   characterised in that
   the light guiding element (10) is designed wedge-like.
10. Arrangement according to one of the claims 2-9,
    characterised in that
    it is part of an escape sign luminaire (1).

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