Safety sign light fitting having a light guide element

Abstract

The invention relates to a light guide element (10) for a safety sign light fitting (100), the element comprising a light coupling portion (15), a light guide portion (20) and a cover (25) which is designed to cover the housing (60) of the safety sign light fitting (100) on one side. The light coupling portion (15), the cover (25) and the light guide portion (20) are integral components of the light guide element (10). The light coupling portion (15) and the light guide portion (20) are aligned with one another and the light coupling portion (15) has a smaller thickness than the light guide portion (20). The light guide element (10) has, in the region of the cover (25), two recesses (29) which extend along the light coupling portion (15) and prevent further transmission of the light from the light coupling portion (15) into the cover (25).

Description

[0001] Safety sign luminaire with light guide element

[0002] Description:

[0003] The present invention relates to a safety sign luminaire used, for example, for illuminated indication of the direction of an escape route, wherein a light guide element is used to backlight the pictogram used for this purpose. In particular, the present invention relates to a light guide element for such a safety sign luminaire.

[0004] Different types of so-called safety sign or escape sign luminaires are known from the state of the art, which differ primarily in the way in which the pictogram displayed is illuminated. While older models usually had a cuboid-shaped housing with translucent side walls featuring the pictogram to be displayed and corresponding lamps inside to backlight the side walls, modern and aesthetically pleasing escape sign luminaires generally have an external light guide that projects freely into the room, with the corresponding pictogram positioned on at least one flat side of the light guide. In this case, light is coupled into the light guide at the end and distributed as evenly as possible across it in order to ensure that the pictogram appears as evenly bright as possible across its entire surface.The associated light sources, which are usually LEDs, are then arranged in a relatively small box-like housing, with the light guide positioned on the underside. A lamp of this type is known, for example, from the applicant's EP 4056 889 Ai.

[0005] In this prior-art luminaire, the light guide has been further developed to fulfill additional functions beyond its primary task of distributing the coupled light as evenly as possible and emitting it homogeneously across a flat surface. In particular, in the prior-art solution, the light guide also forms a cover for the open underside of the luminaire housing, in which the aforementioned lamps and the operating components for operating the lamps are located. This has the advantage of eliminating the need for a separate housing cover, thus reducing the number of components.In this case, the complete light-guiding element consists of a light coupling area extending into the housing, a cover area, and the actual light guide area, which are integral components of a single component that is then arranged on the underside of the luminaire housing and closes it. The transition area between the light coupling area and the light guide area was optimized to prevent unwanted lateral light transfer into the cover area. This ensures that the light coupled by the lamps into the light coupling area of ​​the light guide element is transmitted as completely as possible into the light guide area.

[0006] The solution known from the prior art results in the cover of the light guide element being wedge-shaped in the transition area between the light coupling area and the light guide area, bulging in a direction away from the lamps. This leads to somewhat increased manufacturing complexity and, on the other hand, makes a flat finish on the underside of the housing impossible.

[0007] The present invention is therefore based on the task of further developing the solution known from the prior art in order to be able to further optimize the appearance of the luminaire while at least maintaining the same, but ideally even improving, lighting properties.

[0008] This object is achieved by a light guide element having the features of claim 1. Advantageous developments of the invention are the subject of the dependent claims.

[0009] The light guide element according to the present invention, like the light guide element known from the prior art, also has a light coupling section, a light guide section, and a cover provided in the transition region between the light coupling section and the light guide section, with all three sections being an integral part of a single component. However, in contrast to the prior art solution, in which all three components are shaped in a special way, the present invention provides that at least the light guide section, and possibly all three sections, are essentially plate-shaped with a constant thickness, wherein the maximum thickness of the light coupling section is less than the thickness of the light guide section, and furthermore, the light guide element has two recesses running along the light coupling section in the region of the cover.which suppress the transmission of light from the light coupling section into the cover. From a structural and lighting technology perspective, the light guide element according to the invention is thus relatively simple in design, but offers the advantage that a flat cover of the underside of the luminaire housing can be realized in a visually appealing manner, while nevertheless avoiding disturbing light scattering, particularly in the area of ​​the cover. According to the present invention, a light guide element for a safety sign luminaire is proposed, wherein the safety sign luminaire has a housing extending along a longitudinal axis and an elongated illuminant arranged in the housing, and wherein the light guide element has: a) a web-like light coupling section facing the illuminant, which is designed to couple in the light emitted by the illuminant,b) a plate-shaped light guide section with a constant thickness arranged downstream of the light coupling section, which is designed to distribute the light coupled via the light coupling section and to emit it via at least one flat side, c) a cover designed to cover the housing of the safety sign luminaire on one side, wherein the cover is arranged between the light coupling section and the light guide section in such a way that both sections extend from the cover in two opposite directions, wherein the light coupling section, the cover, and the light guide section are integral components of the light guide element, wherein the light coupling section and the light guide section are aligned with one another, and the light coupling section has a smaller thickness than the light guide section,and wherein the light guide element has two recesses in the region of the cover running along the light coupling section, which suppress a transmission of the light from the light coupling section into the cover.,

[0010] Preferably, the recesses extend in the area of ​​the cover on both sides of the light coupling section and are open toward the light coupling section. From the underside, the cover thus appears as a completely closed, flat element. The recesses are preferably wedge-shaped and dimensioned such that they allow the light to be transmitted exclusively from the light coupling section into the light guide section.

[0011] The cover preferably has a flat region with a substantially constant thickness, which extends substantially perpendicular to the light coupling section and light guide section, wherein according to a particularly preferred development it can be provided that the cover additionally has a circumferential edge region which is intended to cooperate in a sealing manner with the housing of the luminaire. In particular it can be provided that the edge region forms a sealing web which is aligned substantially perpendicular to the flat region of the cover and is designed to engage in a corresponding sealing channel in the housing. With a corresponding design of the sealing channel of the luminaire housing, a cover for the housing can be achieved in such a way that the requirements for a so-called higher protection class are also met.In addition to its advantageous lighting and aesthetic properties, the light guide element according to the invention also fulfills another function: reliably sealing the housing of the luminaire, protecting its interior from the ingress of dust and / or moisture. This eliminates the need for any additional covering measures, further simplifying the construction and, ultimately, the installation of the luminaire.

[0012] It can further be provided that locking elements are formed on the outer circumference of the edge region, which interact with corresponding locking elements of the housing. In particular, these can be locking projections, which then interact with corresponding areas of the housing, thus ensuring that the optical fiber element attached to the housing is reliably and permanently attached to it.

[0013] In contrast to the light guide section, which according to the invention has a constant thickness over its entire surface, the thickness of the web-like light coupling section can also change, in particular with increasing distance from the light source. Particularly preferably, it can be provided that the light coupling section is designed to be prism-like in cross-section and that its thickness increases slightly with increasing distance from the light source. The thickness can increase linearly or in a curved configuration, although it would also be conceivable in principle for the thickness of the light coupling section to also remain constant over its entire height. Regardless of the specific design of the light coupling section, however, the thickness of the light guide section is always greater than the (possibly maximum) thickness of the light coupling section.

[0014] As already mentioned, the main task of the light guide element is to make a pictogram to be displayed appear with as uniform and homogeneous brightness as possible. For this purpose, it can be provided that at least one flat side of the light guide section, which is intended for light emission, is provided with a light output structure. This light output structure can in particular be a chaotically formed nanostructure, the density of which ideally increases with increasing distance from the light input section. Such measures are already known in principle from light guide technology and help to ensure that even areas further away from the actual light source are sufficiently brightly illuminated, thus resulting in an overall appealing appearance and also ensuring that the pictogram is displayed in high quality.The light guide element is preferably made of the same material throughout. It can, in particular, be an injection-molded part, which can thus be manufactured relatively easily and with high precision.

[0015] According to the present invention, a safety sign luminaire is also proposed, which comprises a housing extending along a longitudinal axis and an elongated illuminant arranged in the housing. Furthermore, the safety sign luminaire comprises a light guide element designed according to the invention, as explained above.

[0016] The invention will be explained in more detail below with reference to the accompanying drawings. They show:

[0017] Figure i is a perspective view of an escape sign luminaire in which a light guide element according to the invention is used;

[0018] Figures 2 and 3 show two views of the optical fiber element according to the invention shown in isolation;

[0019] Figure 4 is a sectional view of the upper region of the optical fiber element according to the invention;

[0020] Figure 5 is an enlarged view of the transition area between the light coupling section and the light guide section and

[0021] Figure 6 is a sectional view of the luminaire of Figure 1 in the transition area between the housing and the light guide element according to the invention.

[0022] Figure 1 shows a perspective view of an escape sign luminaire designed according to the invention, generally designated by the reference numeral 100, i.e. an escape sign luminaire in which the light guide element 10 according to the invention, which at the same time also forms a cover for the luminaire housing 60, is used.

[0023] The illuminated indication of an escape route, as shown in Figure 1, is thus realized in this case with the aid of a pictogram element 50, which is arranged on a flat side of a plate-shaped light guide, which will be described in more detail below. Light is coupled into this light guide from one side, which is then distributed as evenly as possible over the entire surface via multiple reflections in a known manner and then emitted via the flat side on which the pictogram element 50 is located. As a rule, the pictogram 50 is formed by a film or a thin plate-like part, which is arranged on the outside of the light guide element 10 and fastened there in a suitable manner. However, this aspect plays a rather subordinate role for the present invention, and the implementation of the pictogram and its arrangement on the light guide element 10 could take place in a wide variety of ways.Direct printing of the light guide would also be conceivable in principle.

[0024] In the present case, the light coupled into the light-guiding element 10 originates from an elongated illuminant, which is preferably formed by a linear arrangement of LEDs arranged within the housing 60 of the luminaire 100. The positioning of the LEDs and the design of the light-guiding element 10, described in more detail below, are such that the light from the illuminant is coupled as efficiently as possible, i.e., completely, into the light-guiding element 10 and then emitted via its flat side. Specific measures for this purpose are explained below with reference to Figures 2 to 5, which show the light-guiding element 10 according to the invention in various views.

[0025] Within the housing 60, which extends along the longitudinal axis L defined by the LED illuminant, not only the illuminant is arranged. Furthermore, further electronic components for operating and supplying power to the illuminant are also located within the housing 60. This can, in particular, be a suitable converter that supplies the LEDs with a voltage suitable for their operation. Emergency power supplies in the form of batteries and / or accumulators can also be arranged within the cuboid-shaped housing 60.

[0026] The side and end walls 61 and 62 visible in Figure 1, together with a rear or bottom side (not shown), enclose the inner receiving area of ​​the housing 60, which is then covered from the underside by the light guide element 10 in the manner described in more detail below. Appropriate measures may be located on the rear side of the housing 60 that enable the housing 60 to be attached, for example, to a ceiling of a room or a suitable support element. For example, attaching the luminaire 100 to a support rail of a support rail system would also be conceivable.

[0027] The transmission, uniform distribution, and coupling of the light generated by the illuminant, as well as the covering of the open underside of the luminaire housing 60, is thus achieved with the aid of the aforementioned light guide element 10, which will now be explained in detail. In accordance with the aforementioned tasks, the light guide element 10 according to the invention essentially has three areas or sections:

[0028] - a light coupling section 15,

[0029] - a light guide section 20 and

[0030] - a cover 25.

[0031] All three sub-areas are integrally connected to form a single-piece component, which is preferably manufactured by injection molding. In principle, it would be conceivable for the three sub-areas to be made of different materials, for example, the cover 25 could be made of an opaque material. However, the light guide element 10 according to the invention will generally be made of the same, clear plastic material throughout, with PMMA or PC being suitable materials for this purpose.

[0032] The design and arrangement of the regions 15, 20 and 25 relative to one another can be seen in particular in Figure 4, which shows a sectional view of the upper region of the light guide element 10.

[0033] The primary function of the light coupling section 15 is to absorb and transmit the light emitted by the illuminant as completely as possible. For this purpose, the web-like light coupling section 15 has a narrow end face 16 on its upper side, which—as explained in more detail below with reference to Figure 6—faces the LEDs and is positioned in relation to the LEDs in such a way that their light can enter the light coupling section 15 with as little loss as possible. If necessary, the end face 16 can also have additional structures tailored to the LEDs, such as lenses or the like, which further improve the efficiency of the light coupling.

[0034] Responsible for light emission, i.e., the illumination of the pictogram element 50, is the light guide section 20 following the light coupling section 15, which is designed as a classic light guide in a known manner. The light guide section 20 is plate-shaped with a constant thickness D, such that light is totally internally reflected as many times as possible and is thus transmitted and evenly distributed within the light guide section 20. Incident light rays are then deflected and coupled out via a light coupling structure (not shown in detail in the figures), so that they are emitted laterally via one or both flat sides 21 of the light guide section 20. This depends on whether the pictograms 50 to be backlit are arranged on only one flat side or on both flat sides 21 of the light guide section 20.The light extraction structuring can, in a known manner, be a nanostructuring, preferably chaotic to avoid so-called moiré effects. The density of the structuring can increase with increasing distance from the light coupling section 15 and thus from the illuminant, which takes into account the fact that light is continuously extracted on the path to the end of the light guide section 20 opposite the illuminant. Ultimately, this measure contributes to the pictogram 50 to be backlit appearing uniformly bright across its entire height.

[0035] In the case of a conventional light guide, it would be expected that the light coupling section 15 and the light guide section 20 form a unit and accordingly also have the same thickness. What is problematic in the present case, however, is that - as can be seen in particular from the sectional views in Figures 4 and 5 - in the region of the transition between the light coupling section 15 and the light guide section 20, the cover 25 is provided, integrally connected to them, and extends with plate-shaped cover regions 26 on both sides with respect to the central plane E. Since the cover 25 is also an integral part of the light guide element 10, there is a risk that part of the light coupled into the light coupling section 15 will be passed on into the cover 25 and emitted there undesirably as scattered light.This would not only result in an unsightly appearance of the luminaire 100, but also in a reduction in its efficiency, since the light radiated into the light coupling section 15 would no longer be fully transmitted to the light guide section 20 and used to illuminate the pictogram 50. To prevent this unwanted lateral light coupling into the cover 25, special measures are therefore provided, which will be explained below, particularly with reference to Figure 5.

[0036] As can be seen here, it is provided that the light coupling section 15 and the light guide section 20 have different thicknesses d and D respectively. In the case of the light guide section 20, it is a classic plate-like design, i.e. the thickness D of the light guide section 20 is constant over its entire surface. The web-like light coupling section 15 could also be plate-shaped with a constant thickness d, but is preferably designed more like a prism, with its thickness d increasing slightly with increasing distance from the light source. The thickness can increase linearly or in a curved shape, although in principle the thickness D of the light guide section 20 is always greater than the (possibly maximum) thickness d of the light coupling section 15.This increased thickness D of the light guide section 20 initially results in more of the light transmitted by the light coupling section 15 being able to be captured by the light guide section 20. However, undesired coupling into the lateral regions 26 of the cover 25 is avoided in particular by the fact that the cover 25 has two elongated grooves or recesses 29 on both sides of the light coupling section 15, which, as shown in Figure 5, are wedge-shaped and open towards the top.The thicknesses d, D of the light coupling section 15 and of the light guide section 20 and the dimensions of the recesses 29 are dimensioned and coordinated with one another in such a way that, in accordance with the beam path shown in Figure 5 (shown here is a light beam X which strikes the outer surfaces of the light coupling section 15 and of the light guide section 20 at an angle corresponding to the critical angle a for the total reflection of the material of the light guide element 10), rays totally reflected by the light coupling section 15 must in any case also strike a side wall 21 of the light guide section 20.Since the light coupling section 15 and the light guide section 20 are aligned with one another, all light rays coupled into the light coupling section 15 are forwarded by means of total internal reflection into the light guide section 20 (and distributed there by means of further total internal reflection) without light being able to enter the laterally branching regions 26 of the cover 25. This also applies although, in comparison to solutions known from the prior art, the underside of the cover 25 runs completely horizontally or at a right angle to the plane E of the light guide section 20. In contrast to solutions known from the prior art, this results in a particularly attractive appearance for the design of the transition from the housing 60 to the actual light guide 20, while still achieving excellent lighting properties.

[0037] The cross-sectional shape of the recesses 29 could also be chosen differently. The decisive factor is that, due to their positioning and design, they prevent light rays entering the light coupling section 15 from penetrating the cover 25 laterally. The wedge shape chosen in the illustrated embodiment is particularly advantageous in that it fulfills the aforementioned lighting properties while simultaneously not resulting in excessive material reduction in the area where the light coupling section 15, the light guide section 20, and the cover 25 meet, so that the light guide element 10, viewed as a whole, has sufficient stability.

[0038] The cover 25 should not only simply cover the underside of the luminaire housing 60, but ideally close it in such a way that the ingress of dust and / or moisture is prevented.

[0039] For this purpose, the cover 25 is provided with a circumferential edge region 30, which is designed to engage in a corresponding sealing channel of the luminaire housing 60. This edge region 30 forms a circumferential web extending essentially perpendicular to the flat cover region 26, which is additionally provided on its outer side with reinforcing ribs 32 and with locking elements 33, as shown in Figure 2. In particular, the locking elements 33 serve to interact with corresponding recesses in the housing 60 of the luminaire 100 to ensure that the light guide element 10 is fastened to the luminaire housing 60 not only in a clamping manner, but also in a force-fitting and thus reliable manner.The design of these locking elements 33 can be provided in such a way that the locking of the light guide element 10 with the lamp housing 60 can only be released with the aid of an appropriate tool, for example a small screwdriver.

[0040] The interaction of the edge region 30 of the cover 25 with the luminaire housing 60 can be seen in the sectional view of Figure 6, wherein it can be seen that the housing 60 has a channel 65 which is open towards the underside and encloses the actual receiving area of ​​the housing, in which a seal 66 is arranged. The edge region 30 of the cover 25 engages in this channel 65 when arranged on the luminaire housing 60, with the upper end 31 of the edge region 30 then dipping into the seal 66, so that the open underside of the housing 60 is sealed very reliably.

[0041] As can also be seen from Figure 6, when the light guide element 10 is mounted on the luminaire housing 60, the lower cover region 26 rests against the underside of the housing 60 and accordingly closes it off, wherein, starting from the cover 25, the light coupling region 15 extends into the interior of the luminaire housing 60 and the light guide section 20 is continued outwards or downwards. The light coupling section 15 is positioned such that the end face 16 faces the LEDs 71. Reliable positioning or alignment of the light coupling section 15 with respect to the LED illuminant 70 can be achieved by pins or projections 19 provided on the upper side of the light coupling section 15, which engage in corresponding recesses in a circuit board 72 carrying the LEDs 71 and thus ensure that they are arranged in a fixed relationship to one another.

[0042] Additional circular receptacles 28 can be provided on the horizontally extending cover areas 26 of the cover 25, which serve to hold lens-like elements 55. With their help, the light from individual LED light sources can be used to specifically illuminate areas below or diagonally below the luminaire 100. These so-called ERI (Escape Route Illumination) spots can therefore be used to additionally illuminate the escape route in addition to displaying it. Overall, the innovative light guide element enables the realization of escape sign luminaires that are positively distinguished by their attractive appearance and their lighting properties. Furthermore, they are reliably protected from external influences, thus meeting the requirements for a higher protection class.

Claims

Claims:

1. A light guide element (10) for a safety sign luminaire (100), which has a housing (60) extending along a longitudinal axis (L) and an elongated illuminant (70) arranged in the housing, wherein the light guide element (10) has: a) a web-like light coupling section (15) facing the illuminant (70), which is designed to couple in the light emitted by the illuminant (70); b) a plate-shaped light guide section (20) arranged downstream of the light coupling section (15) and having a constant thickness (D), which is designed to distribute the light coupled in via the light coupling section (15) and to emit it via at least one flat side (21); c) a cover (25) designed to cover the housing (60) of the safety sign luminaire (100) on one side, wherein the cover (25) is arranged between the light coupling section (15) and the light guide section (20); such thatthat both sections (15, 20) extend from the cover (25) in two opposite directions, - wherein the light coupling section (15), the cover (25) and the light guide section (20) are an integral part of the light guide element (10), - wherein the light coupling section (15) and the light guide section (20) are aligned with each other and the light coupling section (15) has a smaller thickness than the light guide section (20), and - wherein the light guide element (10) has, in the region of the cover (25), two recesses (29) running along the light coupling section (15), which suppress a transmission of the light from the light coupling section (15) into the cover (25).

2. Light guide element for a safety sign luminaire according to claim 1, characterized in that the recesses (29) each run in the region of the cover (25) on both sides of the light coupling section (15) and are open in the direction of the light coupling section (15).

3. Optical fiber element according to claim 2, characterized in that the recesses (29) are each wedge-shaped. 4- Optical fiber element according to one of claims 1 to 3, characterized in that the light coupling section (15) is designed in a prism-like manner and its thickness (d) increases with increasing distance from the illuminant.

5. Optical fiber element according to one of claims 1 to 3, characterized in that the light coupling section (15) is designed in a plate-like manner with a constant thickness (d).

6. Optical fiber element according to one of the preceding claims, characterized in that the cover (25) has a flat region (26) with a substantially constant thickness, which extends substantially perpendicular to the light coupling section (15) and optical fiber section (20).

7. Light guide element according to one of the preceding claims, characterized in that the cover (25) has a closed peripheral edge region (30) which cooperates in a sealing manner with the housing (60) of the luminaire (100).

8. Optical fiber element according to claim 7, characterized in that the edge region (30) forms a sealing web which is aligned substantially perpendicular to the flat region (26) of the cover (25) and which is designed to engage in a corresponding sealing channel (65) of the housing (60).

9. Optical fiber element according to claim 8, characterized in that locking elements (33), preferably locking projections, are formed on the outer circumference of the edge region (31) of the cover (25), which are designed to cooperate with corresponding locking elements of the housing (60).

10. Optical fiber element according to one of the preceding claims, characterized in that the at least one flat side (21) of the optical fiber section (20), which is provided for emitting light, is provided with a light coupling structure, wherein the light The coupling-out structure is preferably a chaotically formed nano-structure whose density increases with increasing distance from the light coupling area.

11. Optical fiber element according to one of the preceding claims, characterized in that it consists entirely of the same material.

12. Optical fiber element according to one of the preceding claims, characterized in that a side (16) of the light coupling section (15) intended for light coupling is provided with positioning projections (19) which cooperate with a carrier element (72) of the illuminant (70) in order to ensure a defined arrangement of the illuminant (70) with respect to the light coupling section (15).

13. Safety sign luminaire (100), comprising: a housing (60) extending along a longitudinal axis (L), an elongate illuminant (70) arranged in the housing, a light guide element (10) according to one of the preceding claims.

14. Safety sign luminaire according to claim 13, characterized in that the illuminant (70) has an elongated arrangement of LEDs (71).

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