Emergency light with light guide element

Description

[0001] The present invention relates to an emergency exit sign light which has a plate-shaped light guide element by which an emergency exit symbol is illuminated over a flat area.

[0002] There are various types of emergency exit lights. Modern and durable emergency exit lights typically feature an external light guide, and at least one emergency exit or safety sign with a pictogram, such as an escape route direction, is usually attached to the flat sides of this light guide. Due to this design, the external light guide, and therefore the pictogram attached to its flat sides, is exposed to environmental influences. To protect the emergency exit light from these external influences, it is necessary to ensure the best possible chemical and mechanical resistance.

[0003] US Patent 2011 / 0219648 Al concerns an LED edge-lit sign comprising a transparent light panel, an image-bearing film in front of the light panel, and a reflective back panel behind the light panel. The image to be displayed is printed onto the image carrier, and a translucent layer of white ink is applied evenly over the printed image.

[0004] From EP 2 709 088 A2, a luminaire, in particular a safety / or escape route sign luminaire, is known which has a transparent light guiding and distribution plate, a number of LEDs assigned to at least one light entry edge of the light guiding and distribution plate and at least one pictogram assigned to a lateral light emission surface of the light guiding and distribution plate.

[0005] US patent 2011 / 0119972 A1 describes a safety step plate and its manufacturing process. The safety step protection device comprises a base component with a communication element through which a light-emitting component is visible. A communication protection element reinforces and strengthens the communication element and mitigates damage to the light-emitting component.

[0006] The chemical resistance of emergency exit lights is usually achieved by manufacturing the light from a material suitable for the required chemical resistance. This can be easily accomplished using various plastics. A greater challenge arises with surfaces printed with pictograms, such as those used on emergency exit lights. To ensure the resistance of these surfaces as well, they are installed within the light in a protected form, preventing their exposure to the surrounding environment. For example, the emergency exit symbols, in the form of a printed film, are inserted into a transparent housing section of the light, which, together with another housing section, forms a closed and tightly sealed space.In this way, the printed surface can be protected from both chemical and mechanical external influences.

[0007] However, to create an emergency exit sign as described above, an additional component is needed to achieve the required chemical and mechanical resistance, and the manufacturing process of such an emergency exit sign is complex, as the foil printed with the escape route symbol has to be inserted into the multi-part housing.

[0008] The invention is based on the objective of providing an emergency exit sign light which has high chemical and mechanical resistance, similar to, for example, a damp-proof light, without using an additional housing part that is necessary for this purpose, thereby simplifying the manufacturing process.

[0009] This problem is solved by an emergency exit sign according to independent claim 1. Specific embodiments of the invention are specified in the dependent claims.

[0010] According to the invention, an emergency exit sign is provided, comprising a plate-shaped light guide element and light sources arranged on a narrow side of the light guide element, which forms a light-input side of the light guide element. The light guide element is designed to emit the light emitted by the light sources and reflected via the light-input side through at least one flat surface arranged substantially perpendicular to the light-input side, with an emergency exit symbol being provided on the flat surface of the light guide element intended for light emission. According to the invention, the emergency exit symbol is applied to a pictogram film, preferably printed on it, which, with its surface bearing the emergency exit symbol facing the light guide element, is attached to the light guide element in a frame-like manner such that the emergency exit symbol is sealed between the pictogram film and the light guide element.

[0011] The resulting emergency exit sign exhibits both the desired chemical and the necessary mechanical resistance to environmental influences, eliminating the need for a separate component. This is achieved through the frame-like attachment of the pictogram film to the light guide element. This design effectively seals the emergency exit symbol, which is printed on the surface of the pictogram film facing the light guide element, between the film and the element. As a result, the emergency exit symbol is shielded from the environment on one side by the pictogram film itself, and on the other side by the light guide element, to which the pictogram film is attached in a frame-like manner.In this case, the pictogram foil is attached to the light-guiding element in such a frame-like manner that the escape route symbol is sealed between the pictogram foil and the light-guiding element, so that the escape route symbol is completely, i.e., on all sides, protected from chemical and mechanical influences.

[0012] The environment is protected. In particular, the frame-like attachment of the pictogram film to the light-guiding element simplifies the manufacture of an emergency exit sign according to the invention, since no additional component is required for the chemical and mechanical resistance of the emergency exit sign and thus sufficient protection against external influences can be achieved solely through the step of frame-like attachment of the pictogram film to the light-guiding element.

[0013] Furthermore, it is preferably intended that the pictogram foil be attached to the light-guiding element in a frame-like sealed manner using a welding process. This ensures a reliable seal of the escape route symbol against external influences. Methods such as laser welding, friction welding, or ultrasonic welding are possible, but other welding processes are also conceivable. In such a welding process, the materials of the pictogram foil and the light-guiding element are fused together, so that both components merge seamlessly in the joint area.

[0014] According to another version of the emergency exit sign, the pictogram film and / or the light guide element are made of PMMA. The use of polymethyl methacrylate as the material for the pictogram film and / or the light guide element increases the chemical and mechanical resistance of the emergency exit sign to external influences. The use of other materials, such as PC and / or PA12, would also be conceivable, provided they possess the required resistance.

[0015] Furthermore, it is preferably provided that the light guide element has light extraction structures, such as scattering or prism structures, on the flat side intended for light extraction. This improves the uniform and effective light emission across the entire flat side of the light guide element intended for light extraction.

[0016] In a preferred embodiment, the surface of the pictogram film is printed using digital printing. This is a technically proven and durable method for applying the escape route symbol to the pictogram film.

[0017] In a particularly preferred embodiment, a microgap is formed between the pictogram film and the light-guiding element, preventing the pictogram film from adhering to the light-guiding element over a large area, except in the area of ​​the frame-like mounting. The microgap has a maximum thickness of 1 mm; preferably, it is thinner than 0.1 mm and thus invisible to the naked eye. The microgap is created by the roughness on the mutually facing surfaces of the light-guiding element and the pictogram film. Thus, except in the area of ​​the frame-like mounting, the pictogram film only makes contact at specific points on the roughness peaks of the light-guiding element, thereby creating the microgap. Such a microgap between the pictogram film and the light-guiding element optimizes homogeneous light output, even with a thin light-guiding element.In particular, the microgap between the pictogram film and the light guide element prevents an excessively high local coupling rate of light near the coupling area, i.e., the area of ​​the light guide element facing the light source, and thus avoids uneven brightness on the flat side of the light guide element intended for light emission. As a result, the light guide element can have a reduced thickness compared to previous light guides in emergency exit signs, enabling a material-optimized design of the light guide element with a thickness of less than 10 mm, preferably 4 mm.

[0018] According to another embodiment, the microgap is formed by the frame-like attachment of the pictogram film to the light guiding element.

[0019] In a preferred embodiment, the light-guiding element has a polygonal shape, in particular a rectangular shape. This allows the light-guiding element to be adapted to the shape of the emergency exit symbol. However, the concept according to the invention can, in principle, be applied to any shape for the light-guiding element.

[0020] In a particularly preferred embodiment, the light guide element is arranged on a base tray used as a housing, which is designed to accommodate the light source and, optionally, electrical and / or electronic components for operating the light source. In this way, the light source and, optionally, the electrical and / or electronic components for operating the light source are protected from external influences, and the chemical and mechanical resistance of the emergency exit sign is improved.

[0021] Furthermore, the base of the light fixture advantageously features mounting areas for installation on a support structure, such as a ceiling. This ensures secure and effective mounting of the light fixture in a suitable location.

[0022] It can be provided that a pictogram film is arranged symmetrically on both flat sides of the light guide element, with the light guide element in this case being designed to emit light from both flat sides. This allows the emergency exit sign to be used from both sides, thus enabling better adaptation to the given circumstances. Of course, a variant in which light is emitted from only one side of the light guide element would also be conceivable.

[0023] The invention will be explained in more detail below with reference to exemplary embodiments and the drawing. The drawing shows: Figure 1 is a perspective view of a first exemplary embodiment of an emergency exit sign according to the invention; Figure 2 is a perspective view of the first exemplary embodiment of an emergency exit sign according to the invention, wherein the pictogram film is not yet attached to the light-guiding element in a frame-like manner; Figure 3 is a side sectional view of the first exemplary embodiment of an emergency exit sign according to the invention; Figure 4 is an enlarged area of ​​the representation of Figure 3 , in which the attachment of the pictogram film to the light-guiding element is shown; Figure 5 a schematic side sectional view of a second exemplary embodiment of an emergency exit sign according to the invention; and Figure 6 an enlarged area of ​​the representation of Figure 5 , where the area of ​​double-sided attachment of two pictogram foils is shown enlarged.

[0024] The in the Figures 1 to 4The illustrated emergency exit sign 1 according to the invention comprises a plate-shaped light guide element 2 and light sources 3, which are arranged on a narrow side of the light guide element 2, which forms a light coupling side 23 of the light guide element 2. The light sources 3 can, for example, be formed by an elongated LED board on which LEDs are arranged such that the light emitted by the LEDs is coupled into the light guide element 2 as uniformly as possible over the entire length of the light coupling side 23 of the light guide element 2. Optionally, the light guide element 2 can have special light coupling structures facing the light sources – for example, lens-like light coupling structures – which optimize the coupling efficiency and the uniform distribution of the light.

[0025] The light guide element 2 is designed such that the light coupled in via the light coupling side 23 is distributed homogeneously within the light guide element 2 by means of total internal reflection in a known manner, so that a uniform luminous density is achieved over its entire height. It is provided that the light is coupled out via at least one flat side 21 of the light guide element 2, which is arranged substantially perpendicular to the light coupling side 23, so that light is emitted in a planar and homogeneous manner via this flat side 21 of the light guide element 2.

[0026] An escape route symbol 6 is provided on the flat surface 21 of the light-guiding element 2, which is intended for light emission. The escape route symbol 6 is printed on a pictogram film 4, which is attached to the light-guiding element 2 with its surface bearing the escape route symbol facing it. The light emitted from the flat surface 21 of the light-guiding element 2 illuminates the escape route symbol, making it visible to an observer looking at the escape route sign 1 from the outside. However, the pictogram film 4 is not attached to the light-guiding element 2 across its entire surface, but rather in a frame-like manner, such that the escape route symbol 6 is sealed between the pictogram film 4 and the light-guiding element 2.

[0027] The Figure 1As already mentioned, the figure shows a perspective view of a first exemplary embodiment of such a rescue sign luminaire according to the invention 1. Figures 2 and 3 They show the same emergency exit sign 1, whereby in Figure 2 the pictogram foil 4 is not yet attached to the light guiding element 2 and Figure 3 a sectional view of the emergency exit sign 1 with a Figure 4 The enlarged area A shown represents the emergency exit sign 1 according to the invention, corresponding to the previously described operating principle. The pictogram film 4 is applied to a flat side 21 of the light-guiding element 2 according to the invention, wherein the flat side 21 is designed to emit light and the pictogram film 4 is attached to the light-guiding element 2 in a frame-like manner.

[0028] The pictogram film 4 features an escape route symbol 6, printed on the surface of the pictogram film 4 facing the light guide element 2. The escape route symbol 6 is thus sandwiched between the pictogram film 4 and the light guide element 2. The pictogram film 4 is fully and completely enclosed around its perimeter, forming a frame around the light guide element 2. While the central area of ​​the pictogram film 4, containing the escape route symbol 6, is not directly connected to the light guide element 2, it is nevertheless completely sealed and protected from external influences. This sealed attachment of the pictogram film 4 to the light guide element 2 is preferably achieved by laser welding around the perimeter of the pictogram film 4. However, bonding, laminating, or embossing are also possible.In the case of preferred welding, laser welding, friction welding, or ultrasonic welding can be used, although other welding processes are also conceivable in principle. During such a welding process, the materials of the pictogram film and the light guide element are fused together, so that both components merge seamlessly in the joint area. With a clean weld, the connection is indistinguishable from other types of joints to the naked eye; only under a microscope would a difference be discernible, for example, between the welding process and an adhesive bonding process.

[0029] In order to achieve good resistance of the emergency exit sign 1 against external influences, the light guide element 2 and / or the pictogram film 4 are made of suitable plastics such as PC, PA12 or PMMA; preferably both the light guide element 2 and the pictogram film 4 are made of PMMA.

[0030] As in Figure 4As shown, a microgap 42 is formed between the pictogram film 4 and the light guide element 2 in the central area enclosed by the frame-like mounting area, between the pictogram film 4 and the surface of the light guide element 2, so that the pictogram film 4 has no adhesion to the light guide element 2 apart from the frame-like mounting. This microgap 42 improves the homogeneous light distribution in the light guide element 2 and thus also the uniform light emission across the flat side 21 of the light guide element 2, resulting in improved visibility of the backlit escape route symbol 6.

[0031] Figure 2The figure shows the luminaire 1 in a state where the pictogram film 4, on which the escape route symbol 6 is printed, is not yet attached to the light guide element 2. The pictogram film 4 is preferably transparent, so that the escape route symbol 6, which is printed on the surface 41 of the pictogram film 4 facing the light guide element 2, is visible from the side opposite this surface 41, particularly when the escape route luminaire 1 is in operation. The escape route symbol 6 is designed as a completely colored area, so that areas which are usually transparent in an escape route symbol 6, such as the escape route arrow, are not transparent, but of course still allow light to pass through. In particular, printing the pictogram film 4 with white ink is suitable for these areas.Therefore, overall, pictogram foil 4 has no transparent areas in the area where the escape route symbol 6 has been applied.

[0032] In Figure 3 In the diagram, which shows a cross-sectional view of the luminaire 1, the light coupling side 23, arranged perpendicular to the flat side 21, is particularly visible. As already mentioned, the light coupling side 23 of the light guiding element 2 is designed to receive the light from the light sources 3, which are also located in Figure 3 The figures show how emitted light is coupled into the light guide element 2. Furthermore, the light guide element is designed to emit the light coupled through the light coupling side 23 via the flat side 21, which is arranged essentially perpendicular to the light coupling side 23.

[0033] In Figure 1Furthermore, a base 5 is visible, which serves as a luminaire housing and on which the light guide element 2 is arranged. The base 5 also serves to receive or hold the light sources 3 and, if applicable, electrical and / or electronic components for operating the light sources 3, such as an LED converter. The light guide element 2 is arranged on the base 5 with its light coupling side 23 in such a way that the light emitted by the light sources 3 is coupled into the light guide element 2 through the light coupling side 23.

[0034] The base tray 5 also has fastening areas 51 on the outwardly oriented surface of the base tray 5 opposite the light guiding element 2 for mounting on a support element, such as a ceiling.

[0035] In the area of ​​Ain Figure 3 , which enlarges in Figure 4As shown, the arrangement of the pictogram film 4 on the flat side 21 of the light-guiding element 2 is visible. As previously described, the pictogram film 4 is attached only in a frame-like manner, so that, apart from the edge area of ​​the pictogram film 4, no adhesion of the pictogram film 4 to the light-guiding element 2 occurs, and a microgap 42 is formed between the pictogram film and the light-guiding element 2. Adhesion between the two components is avoided by the fact that one or both of the surfaces facing each other, of the light-guiding element 2 and the pictogram film 4, have a certain roughness. The pictogram film 4 then only rests at specific points on the resulting roughness peaks, which, overall, or when viewed across the entire surface, creates the microgap 42 between the two components.This is preferably smaller than 1 mm, particularly preferably smaller than 0.1 mm and therefore, in principle, not detectable.

[0036] The micro-slit 42 promotes homogeneous light emission from the light-guiding element 2 across the entire surface of the pictogram film 4, as the total internal reflection properties of the light-guiding element 2 are significantly enhanced by the micro-slit 42. This allows for homogeneous luminous intensity throughout the entire light-guiding element 2 and therefore also homogeneous light emission across the flat surface 21 of the light-guiding element 2. Due to this micro-slit 42, unintentional light leakage from the light-guiding element 2 is largely prevented, and homogeneous luminous intensity within the light-guiding element 2 is achieved.

[0037] To achieve the intended, effective extraction via the flat side 21 of the light guide element 2, the flat side 21 of the light guide element 2, which is covered by the pictogram film 4, has light extraction structures 22. These light extraction structures 22 can be formed, for example, by scattering or prism structures, and in particular also by microprism structures.

[0038] If these light extraction structures 22 are provided on the flat side 21 where the pictogram film 4 is also located, then these light extraction structures 22 can simultaneously provide the aforementioned surface roughness through which the microgap 42 is formed. If, on the other hand, the light extraction occurs through structures located on the opposite side of the light guide element 2, or with the aid of scattering particles contained in the material of the light guide element 2, then the flat side 21 of the light guide element 2 may additionally be provided with a certain degree of roughness.

[0039] Ultimately, the described measures allow the light guide element to be made exceptionally thin. In particular, it can have a thickness of less than 10 mm, preferably less than 4 mm.

[0040] The in the Figures 5 and 6The second exemplary embodiment of the emergency exit sign 1 shown is, in its basic structure, the same as the emergency exit sign 1. Figures 1 to 4 similarly, wherein in this second exemplary embodiment the light guide element 2 is designed such that it emits light in a mirror-symmetrical manner via both flat sides 21 of the light guide element 2.

[0041] The in Figure 6The enlarged area B shows the arrangement for coupling the light from the light guide element 2 via the flat side 21 of the light guide element 2. In this second exemplary embodiment, the light guide element 2 is designed to emit light mirror-symmetrically via both flat sides 21 of the light guide element 2. For this purpose, a pictogram film 4 is arranged mirror-symmetrically on each of the flat sides 21 according to the invention, using one of the fastening methods already described. The frame-like fastening of the pictogram film 4 to the light guide element, as in the previous embodiment, ensures that the light is emitted in a mirror-symmetrical manner. Figures 1 to 3A microgap 42 is formed, which improves the uniform light emission across the flat surface 21 of the light-guiding element 2 covered by the pictogram film 4. To optimize the light extraction from the light-guiding element 2, the light-guiding element 2, as in the previous embodiment, has light extraction structures 22 in the area of ​​the flat surfaces 21 covered by the pictogram films 4.

[0042] The resulting emergency exit sign 1 is therefore particularly resistant to external influences, both chemically and mechanically. The escape route symbol 6 is sealed by the pictogram film 4 and the light-guiding element 2, protecting it from external chemical and mechanical damage, thus resulting in a particularly durable and resistant emergency exit sign 1.

Claims

1. Emergency exit sign (1), comprising: - a plate-shaped light guide element (2) and - light sources (3) arranged on a narrow side of the light guide element (2), which forms a light coupling side (23) of the light guide element (2), wherein the light guide element (2) is designed to emit the light emitted by the light sources (3) and introduced via the light coupling side (23) via at least one flat side (21) arranged substantially perpendicular to the light coupling side (23), and wherein an escape route symbol (6) is provided on the flat side (21) of the light guide element designated for light emission, characterized in that the escape route symbol (6) is applied to a pictogram film (4), preferably printed, which is attached to the light guide element (2) in a frame-like manner with its surface bearing the escape route symbol (6) facing the light guide element (2) in such a way that the escape route symbol (6) is sealed between the pictogram film (4) and the light guide element (2).

2. Emergency exit sign according to claim 1, characterized in that the pictogram film (4) is attached to the light guide element (2) in a sealed, frame-like manner using a welding process.

3. Emergency exit sign according to claim 2, characterized in that the welding process is a laser welding process, a friction welding process, or an ultrasonic welding process.

4. Emergency exit sign according to one of the previous claims, characterized in that the pictogram film (4) and / or the light guide element (2) are made of PMMA and / or PC and / or PA12.

5. Emergency exit sign according to one of the previous claims, characterized in that the light guide element (2) comprises light coupling structures (22), such as scattering or prism structures, on the flat side (21) designed for light coupling.

6. Emergency exit sign according to one of the previous claims, characterized in that the surface (41) of the pictogram film (4) is printed using digital printing.

7. Emergency exit sign according to one of the previous claims, characterized in that a microgap (42) is formed between the pictogram film (4) and the light guide element (2).

8. Emergency exit sign according to claim 7, characterized in that the microgap (42) is formed by the pictogram film (4) being placed at specific points on roughness peaks of the surfaces of the light guide element (2) and / or the pictogram film (4) facing each other.

9. Emergency exit sign according to claim 7 or 8, characterized in that the microgap (42) is thinner than 1 mm, preferably thinner than 0.1 mm.

10. Emergency exit sign according to one of the previous claims, characterized in that the light guide element (2) has a polygonal shape, in particular a rectangular shape.

11. Emergency exit sign according to one of the previous claims, characterized in that the light guide element (2) has a thickness of less than 10 mm, preferably a thickness of about 4 mm.

12. Emergency exit sign according to one of the previous claims, characterized in that the light guide element (2) is arranged on a base tray (5) which is designed to accommodate the light source (3) and, if applicable, electrical and / or electronic components (31) for operating the light source (3).

13. Emergency exit sign according to claim 12, characterized in that the base tray (5) comprises mounting areas (51) for mounting on a support element, such as a ceiling.

14. Emergency exit sign according to one of the previous claims, characterized in that a pictogram foil (4) is arranged on both flat sides (21) in a mirror-symmetrical manner on both sides of the light guide element (2), wherein the light guide element (2) is designed to emit light via both flat sides (21).