DE102021214575A1 - Lighting device for emitting light and vehicle - Google Patents

Abstract

The invention relates to a lighting device (10) for emitting light, having: - a light guide (100) which is designed to guide light essentially along a light travel direction (101) within the light guide (100), - a holder (200 ), which is designed to accommodate the light guide (100), - a diffuser (300), which is arranged on the light guide (100) and designed to at least partially scatter light coupled out from the light guide (100), with a diffuser extension ( 301) in the hotspot area (400). The diffuser extent (301) in the hotspot area (400) is greater than a diffuser extent (301) in the rest of the diffuser (300). Furthermore, a compensation area (500) is provided in the hotspot area (400), which is designed to compensate for the greater diffuser expansion (301) in the hotspot area (400). The invention also relates to a vehicle (20) with a lighting device (10).

Description

The invention relates to a lighting device for emitting light and a vehicle.

Demands on and possible uses of lighting devices, particularly in the field of vehicle lighting, have recently increased further. The use of LED lamps results in more freedom for the structural and aesthetic design of lighting systems, as they consume less energy and generally take up less space than other lamps.

Further freedom in the design of lighting systems results from the use of light guides, which allow the light source to be arranged at a distance from the point that is actually to be illuminated. Light guides are usually made of plastic or glass. Since these are often not self-supporting, especially with low material thicknesses, or the unavoidable, slightly unintentionally decoupled radiation should not be visible to the outside, these light guides are often at least partially supported and/or covered by a holding structure made of other components.

Light that is guided through a light guide is usually at least partially coupled out of the light guide at the end of the light guide. However, it can also be provided that the light should be decoupled within a specific range. This can be achieved by different measures. In order to achieve homogeneous illumination, it is usually necessary to combine an (optical) diffuser with the light guide. Diffusers break up and/or scatter incident light, resulting in more homogeneous radiation.

Despite the use of diffusers, however, the problem can arise that the emitted light is not sufficiently homogenized for the intended purpose. This can occur in particular in areas in which the radiation emitted by the light guide is already very inhomogeneous. This creates so-called "hotspots", i.e. places where there is a locally increased radiation intensity compared to the rest of the area. This is the case, for example, at the points where two or more light guides are brought together or another radiation source is coupled in. Particularly tight curve radii, phase transitions outside of the light guide or the end of a light guide can also be the cause of the presence of a hotspot area.

In order to make such hotspot areas invisible to the user, the corresponding area is usually hidden from the user by covering it with a cover or moving it to an area that is not visible to the user. In general, but especially in vehicles, installation space is limited. In addition, it causes higher material costs to provide a light guide that is longer than the area to be illuminated in order to move hotspot areas such as at the end of the light guide into covered areas.

It is an object of the present invention to at least partially eliminate the above disadvantages known from the prior art. In particular, it is an object of the present invention to provide a lighting device and a vehicle that enables homogeneous lighting and at the same time requires little installation space, has reduced material consumption and is inexpensive.

The above object is achieved by a lighting device having the features of claim 1 and a vehicle having the features of claim 9. Further advantages of the invention result from the dependent claims, the description and the drawings.

According to a first aspect of the invention, a lighting device for emitting light is provided, having a light guide that is designed to guide light essentially along a light propagation direction within the light guide and in particular to decouple it at predetermined areas, a holder that is designed to to receive the light guide, and a diffuser, which is arranged on the light guide and is designed to at least partially scatter light coupled out of the light guide, with a diffuser extension in a hotspot area in the diffuser. In this case, the diffuser expansion in the hotspot area is greater than a diffuser expansion in the rest of the diffuser. Furthermore, a compensation area is provided in the hotspot area, which is designed to compensate for the greater diffuser expansion in the hotspot area in such a way that the diffuser forms an essentially planar surface.

A lighting device of this type enables homogeneous illumination by increasing the extent of the diffuser in the hotspot area. By providing the compensation area, the larger diffuser expansion can also be compensated for structurally, so that no additional cover has to be provided or the light guide has to be lengthened, which saves material and costs.

The term lighting device means an assembly that is primarily designed to emit light with a predetermined emission characteristic. Provision can be made for the lighting group to have further components, in particular at least one light source. The light source can be, in particular, a light-emitting diode (LED).

Light primarily refers to electromagnetic radiation in the range visible to humans. However, for special applications it can be provided that other wavelengths, for example in the infrared or UV range, are also emitted by the lighting device. Likewise, light is understood to mean both monochromatic radiation and radiation with a large number of different wavelengths.

A light guide is a device capable of transporting electromagnetic radiation over a predetermined distance. In particular, total reflection due to a lower refractive index of the medium surrounding the light guide, due to mirroring of the interface or a suitable refractive gradient are conceivable as transport mechanisms. Provision can be made for the light guide to be in the form of an optical waveguide (also referred to as a fiber optic cable). Optical waveguides have at least one fiber that guides the light. Provision can be made for the at least one fiber to have glass, in particular quartz glass, or plastic or, in particular, to be made entirely of one of the two materials.

A holder should be understood to mean a constructive unit which is essentially designed to hold the light guide in an intended position. Provision can also be made for the holder to absorb or reflect the radiation from the light guide at different positions. In order to enable the greatest possible light yield, it can be provided that the mount has a high level of reflectivity and, in particular, is embodied in white.

A diffuser is an optical component that is designed to homogenize light that hits the diffuser by scattering. For this purpose, a large number of scattering centers can be provided in the diffuser, at which the light is scattered. In particular, the diffuser can at least comprise or consist of glass or plastic, in particular polymethyl methacrylate PMMA.

Without countermeasures, the intensity of the light emitted by the diffuser is inhomogeneous in a hotspot area. In particular, a hotspot area can be at least in an end area of the light guide, in a coupling area in which light (from a radiation source) is coupled into the light guide, in a connection area in which another light guide is connected to the light guide, or in a bending area which has a tight radius of curvature. The remaining area of the light guide, the mount, the diffuser or other components of the lighting device means the areas that do not cause any hotspot areas in the light emitted by the diffuser. In these other areas, the light emitted by the diffuser is essentially homogeneous even without further measures.

According to the invention, the diffuser expansion in the hotspot area is greater than a diffuser expansion in the rest of the diffuser. In other words, the diffuser has at least two material thicknesses. In particular, a thickness in the direction of the intended direction of light propagation can be meant here, so that the light coupled out from the light guide takes a longer path through the diffuser in the hotspot area than in the remaining area of the light guide.

The compensation area is to be understood as meaning a predetermined section of the lighting device in which the larger diffuser expansion in the hotspot area is compensated for by design measures. This means adjustments to the geometry of at least the light guide or the position. In other words, the provision of the compensation area ensures that the emission of the light is homogeneous without covering the hotspot area or reducing the emission of light from the light guide in the hotspot area.

A substantially planar surface means in particular that the user cannot see any bulge on the side of the diffuser facing away from the light guide, which side represents the intended direction of emission. Nevertheless, the radiating surface of the diffuser can run in curves or have kinks in the overall course of the lighting device. However, the local thickening of the diffuser in the hotspot area cannot be recognized by the user due to the provision of the compensation area.

A vehicle with the lighting device according to the invention can be provided within the scope of the invention. Street and building lighting, pieces of furniture and other items of furniture with the lighting device according to the invention are also conceivable

Provision can be made for the light guide, the holder and the diffuser to be arranged essentially parallel to one another and to form an assembly that is particularly elongated in the direction of light propagation. As a result, even larger areas can be illuminated homogeneously.

Furthermore, it is conceivable in the lighting device that at least the light guide, the holder or the diffuser have at least one bevel or a curved surface. Both the bevel and the curved surface can reduce the inhomogeneous outcoupling of radiation. Provision can in particular be made for this at least one bevel or curved surface to be arranged in a transition area between the remaining area of the light guide, the mount or the diffuser and the hotspot area. As a result, a particularly homogeneous radiation is achieved without the transition of the two areas to the outside being perceptible to a user.

Furthermore, it can be provided that the light guide has recesses which are designed to at least partially decouple the light guided in the light guide from the light guide. As a result, the decoupling of the light can be predetermined in a particularly precise manner, as a result of which a more homogeneous illumination can be achieved.

It is also conceivable in an illumination device according to the invention that in the compensation area at least one light guide extension is smaller than in the rest of the light guide or that a mounting extension is smaller than in the rest of the mounting. In other words, at least the light guide or the holder can be thinner or have a lower material thickness in the hotspot area. This offers the advantage that the necessary installation space remains small, even in the hotspot area. Therefore, at least a smaller extent of the holder or a smaller extent of the light guide can be interpreted as a compensation area.

Provision can be made for the expansion of at least the light guide or the holder to be reduced by exactly the factor by which the expansion of the diffuser is increased, so that the outer geometric dimensions of the light guide, the holder and the diffuser are between the remaining area and the hotspot area remains constant. Due to the constant external dimensions, a lighting device designed in this way can be arranged particularly easily in a component to be illuminated.

It is also conceivable in a lighting device according to the invention for at least the light guide or the holder to be angled in the compensation area. In other words, it can be provided that at least the light guide or the holder does not run straight in the compensation area, but rather has a kink. In this way it can be achieved that the diffuser, which is enlarged in the hotspot area, forms an essentially planar surface on a side facing away from the light guide at the transition from the remaining area to the hotspot area. In other words, the outward thickening of the diffuser cannot be seen by the user.

Provision can also be made for the angling of at least the light guide or the holder to correspond to an angling of the diffuser. In this way, a homogeneous radiation can be achieved in a structurally particularly simple and cost-saving manner.

Furthermore, it is conceivable in a lighting device according to the invention that the holder in the hotspot area is designed to be light-tight, in particular in one piece. In other words, it can be provided that the holder is designed in such a way that almost no light penetrates to the outside through the component itself. With a one-piece design, the light-tightness can be implemented particularly cost-effectively, since there are no gaps that would otherwise have to be provided with seals. The light-tightness also offers the advantage that, on the one hand, no unwanted lighting occurs around the holder and, on the other hand, no light is lost to the outside, which means that the light source would have to use more energy to produce more light.

It is also conceivable in a lighting device according to the invention that the mount in the hotspot area has at least the same reflectivity as the rest of the mount. In other words, it can be provided that the surface of the mount in the hotspot area has the same optical properties as in the remaining area of the mount. In particular, it can be provided that the mount has a reflectivity greater than 0.5, which ensures a particularly high light yield. Due to the fact that the reflectivity is constant across the mount, the manufacture of the mount can also be simplified and costs can be saved. Furthermore, for example, a reduction in the reflectivity in the hotspot area would result in light being lost, so that the light source would consume correspondingly more energy.

Furthermore, it is conceivable in a lighting device according to the invention for the holder to have an opening in the hotspot area on a side of the diffuser facing away from the light guide. In other words, the mount is open in the hotspot area, as in the rest of the area, and has no cover to cover the hotspot area. This offers the advantage that no additional material costs have to be incurred for a longer light barge, a longer bracket or a cover. In addition, no radiation is lost either.

Provision can be made for an external dimension of an assembly of light lighter, holder and diffuser to be the same in the hotspot area as in the rest of the area. In other words, the above three components taken together are just as large in the rest of the area as in the hotspot area. In particular, it can be provided that the assembly has the same cross section in both areas. This offers the advantage that such a lighting device can be inserted particularly easily into the geometry of a component to be illuminated and, moreover, a consistently small installation space is required.

Furthermore, in a lighting device according to the invention, it can advantageously be provided that the diffuser has a homogeneous distribution of scattering centers. In other words, the scattering centers within the diffuser are evenly distributed over the entire area. A particularly homogeneous illumination can be achieved in this way. In addition, the manufacture of the diffuser is simplified since different concentrations of scattering centers do not have to be provided. This also makes production cheaper.

According to a further aspect of the invention, a vehicle having a lighting device according to one of the preceding claims is provided.

A vehicle according to the invention thus brings with it the same advantages as have already been described in detail with reference to a lighting device according to the invention.

A vehicle can mean any type of means of transport, in particular land, air and sea vehicles. Furthermore, provision can advantageously be made for the lighting device to be provided at least in a truck or passenger vehicle.

In a vehicle according to the invention, it can preferably be provided that the lighting device is designed at least as interior lighting or as exterior lighting. In this case, interior lighting means lighting of elements that are located in an interior area of the vehicle. Exterior lighting should be understood to mean both lighting of elements of the vehicle itself, which are located on an outer surface of the vehicle, and lighting of the surroundings of the vehicle or signal lighting. In particular, the exterior lighting can be an area lighting, a number plate lighting, a blinker, or a headlight of a vehicle.

• 1 ein Ausführungsbeispiel der Beleuchtungsvorrichtung, bei der im Kompensationsbereich der Lichtleiter und die Halterung abgewinkelt sind,
• 2 ein Ausführungsbeispiel der Beleuchtungsvorrichtung, bei der eine Lichtleiterausdehnung im Kompensationsbereich kleiner ist als im übrigen Lichtleiter,
• 3 ein Ausführungsbeispiel der Beleuchtungsvorrichtung, bei der Lichtleiter und Diffusor gekrümmte Flächen aufweisen,
• 4 ein Ausführungsbeispiel der Beleuchtungsvorrichtung, bei der Lichtleiter und Halterung eine Fase aufweisen,
• 5 ein Fahrzeug, bei dem eine Beleuchtungsvorrichtung als Interieur- und Exterieurbeleuchtung vorgesehen ist.

Further advantages, features and details of the invention result from the following description, in which exemplary embodiments of a lighting device according to the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. They show schematically:

• 1 an exemplary embodiment of the lighting device in which the light guide and the holder are angled in the compensation area,
• 2 an embodiment of the lighting device, in which a light guide extension in the compensation area is smaller than in the rest of the light guide,
• 3 an embodiment of the lighting device in which the light guide and diffuser have curved surfaces,
• 4 an exemplary embodiment of the lighting device in which the light guide and holder have a bevel,
• 5 a vehicle in which a lighting device is provided as interior and exterior lighting.

In the following description of some exemplary embodiments of the invention, identical reference symbols are used for the same technical features in different exemplary embodiments.

1 12 shows a lighting device 10 for emitting light. The lighting device 10 shown has a light guide 100 which is designed to guide light essentially along a light propagation direction 101 within the light guide 100 and in particular to couple it out at predetermined areas.

Furthermore, the lighting device 10 has a holder 200 which is designed to accommodate the light guide 100 .

In addition, the lighting device 10 shown has a diffuser 300, wel cher is arranged on the light guide 100 and is designed to at least partially scatter a light decoupled from the light guide 100 . The diffuser 300 has a diffuser extension 301. This is, as in FIG 1 seen in one on the right of the 1 Hotspot area 400 shown in the diffuser 300 is larger than a diffuser expansion 301 in the rest of the diffuser 300 on the left in FIG 1 .

Furthermore, in the 1 It can be seen that a compensation area 500 is provided in the hotspot area 400, which is designed to compensate for the larger diffuser extent 301 in the hotspot area 400 in such a way that the diffuser 300 forms an essentially planar surface 305.

The 1 FIG. 12 further shows that the lighting device 10 has a remaining area 600 in which the light guide extension 102 and the diffuser extension 301 are essentially constant. The bracket extension 201 is in the 1 Although not shown in the remaining area 600 for reasons of simplification, it is likewise essentially constant in the exemplary embodiment. The holder extension 201 and the light guide extension 102 are in the embodiment of 1 also constant in the hotspot area 400 or in the compensation area 500. Only the diffuser 300 has a larger diffuser extension 301 in the hotspot area 400 than in the remaining area 600.

In order to ensure that the diffuser 300 also has a substantially planar surface 305 in the hotspot area 400, in the exemplary embodiment shown 1 in the compensation area 500 both the light guide 100 and the holder 200 are angled.

In all of the exemplary embodiments, light which is coupled into the light guide 100 from a light source is guided through the light guide 100 along a light propagation direction 101 . Of course, the electromagnetic radiation does not only propagate parallel to the light propagation direction 101, but is reflected several times (also back) on the way through the light guide. A certain proportion of the radiation is always coupled out of the light guide 100 in this case. This decoupling can be intensified or intensified in certain areas by providing recesses 105 in the light guide 100, at which the light is scattered. The light emerging from the light guide 100 is either absorbed by the mount 200 or reflected back into the light guide 100, or it hits the diffuser 300, which spatially homogenizes the intensity of the light and finally through an opening 202 of the mount 200 to the den Diffuser 300 surrounding environment emits.

Im in the 1 until 4 Hotspot areas 400 shown, one end of the light guide 100 is the cause of the uneven distribution of the light intensity. At the end of the light guide 100, the light is reflected back particularly strongly compared to the remaining part of the light guide, with part of this light reflected back being coupled out directly. However, there can also be other hotspot areas 400, for example in a coupling area in which light is coupled into the light guide 100, in a connection area in which another light guide is connected to the light guide 100 or in a bending area which has a narrow radius of curvature .

The inhomogeneity of the light intensity that occurs is counteracted by the fact that the diffuser 300 has a larger diffuser extension 301 than the remaining area 600 . As a result, the increased, inhomogeneous radiation is scattered more strongly, so that overall the light is emitted again homogeneously. In order to compensate for this non-uniform diffuser expansion 301, a compensation area 500 is again provided, in which the light guide 100 and the holder 200 are angled. This ensures that the diffuser 300 forms an essentially planar surface 305 .

2 shows a further exemplary embodiment of a lighting device 10. As in FIG 1 the diffuser 300 has a larger diffuser extension 301 compared to the remaining area 600 in the hotspot area 400.

In order to compensate for this larger diffuser expansion 301, according to the im 2 illustrated embodiment, however, it is provided that a light guide extension 102 is smaller in the compensation area 500 than in the rest of the light guide 100. Alternatively or in addition, it could also be provided that a holder extension 201 in the compensation area 500 is smaller than in the rest of the holder 200.

The in the 2 until 4 Illustrated embodiments have the common feature that an outer dimension of an assembly of lighter 100, holder 200 and diffuser 300 in the hotspot area 400 is the same as in the rest of the area 600. This allows the lighting device 10 to be particularly easily inserted into areas to be illuminated.

3 shows another embodiment of a lighting device 10. Similar to the embodiment of FIG 1 Here, too, the light guide 100 and the holder 200 are angled. However, the mount 200 has a curved surface 204 and the light guide 100 has a curved surface curved surface 104 on. The curved surfaces 204, 304 offer the advantage that they cause particularly little inhomogeneity in the light emission, so that a more homogeneous light emission can be achieved. A curved surface 304 may also be provided in diffuser 300 with equal benefit.

All of the exemplary embodiments shown have in common that the holder 200 in the hotspot area 400 can be made light-tight, in particular in one piece. This prevents unwanted scattered light from escaping.

Provision can also be made in all exemplary embodiments for the mount 200 to have at least the same reflectivity in the hotspot area 400 as the rest of the mount 200. The mount 200 can preferably be designed white in order to enable a particularly good light yield.

In the 3 it is indicated that the diffuser 300 has a homogeneous distribution of scattering centers 306 . This facilitates the manufacture of the diffuser 300 and thus reduces the manufacturing costs.

4 shows a further embodiment of the lighting device 10. In this is compared to the other embodiments shown 1 until 3 additionally provided that the light guide 100, the holder 200 and the diffuser 300 can each have a bevel 103, 203, 303. This can be attached in particular in the transition from the remaining area 600 to the hotspot area 400 . Similar to curved surfaces, a bevel 103, 203, 303 offers the advantage that it causes particularly little inhomogeneity in the light emission, so that a more homogeneous light emission can be achieved. In addition, chamfers 103, 203, 303 are particularly easy to apply in manufacturing processes that remove material. Chamfers 103, 203, 303 can also be provided in combination with curved surfaces 104, 204, 304.

5 Finally, FIG. 1 shows a vehicle 20 with several lighting devices 10. The vehicle 20 shown is a passenger car. The lighting devices 10 according to the invention can also be provided on other land, water and air vehicles.

As in 5 is also shown, the lighting device 10 can be designed at least as interior lighting 11 or as exterior lighting 12 . In particular, the lighting device 10 can be embodied as a front lighting, license plate lighting, indicator, or as a headlight of a vehicle, in particular a passenger car.

The above explanation of the embodiments describes the present invention exclusively in the context of examples. It goes without saying that individual features of the embodiments can be freely combined with one another, insofar as this makes technical sense, without departing from the scope of the present invention.

Reference List

10

lighting device

11

interior lighting

12

exterior lighting

20

vehicle

100

light guide

101

direction of light

102

fiber expansion

103

bevel of the light guide

104

curved surface of the light guide

105

recesses

200

bracket

201

bracket expansion

202

opening

203

chamfer of the bracket

204

curved surface of the bracket

300

diffuser

301

diffuser expansion

303

bevel of the diffuser

304

curved surface of the diffuser

305

flat surface

306

scattering centers

400

hotspot area

500

compensation area

600

remaining area

Claims (10)

Lighting device (10) for emitting light, comprising: - a light guide (100) which is designed to guide light essentially along a light travel direction (101) within the light guide (100), - a holder (200) which is designed to receive the light guide (100), - a diffuser (300) which is arranged on the light guide (100) and is designed to emit a light conductor (100) to at least partially scatter light coupled out, with a diffuser extension (301) in a hotspot area (400) in the diffuser (300), the diffuser extension (301) in the hotspot area (400) being larger than a diffuser extension (301) otherwise Diffuser (300) and in the hotspot area (400) a compensation area (500) is provided, which is designed to compensate for the larger diffuser extension (301) in the hotspot area (400) in such a way that the diffuser (300) has an essentially planar surface (305 ) forms. Lighting device (10) according to the preceding claim, characterized in that in the compensation area (500) at least one light guide extent (102) is smaller than in the rest of the light guide (100) or one holder extent (201) is smaller than in the rest of the holder (200). Lighting device (10) according to one of the preceding claims, characterized in that in the compensation area (500) at least the light guide (100) or the holder (200) are angled. Lighting device (10) according to one of the preceding claims, characterized in that the holder (200) in the hotspot area (400) is designed to be light-tight, in particular in one piece. Lighting device (10) according to one of the preceding claims, characterized in that the mount (200) in the hotspot area (400) has at least the same reflectivity as the rest of the mount (200). Lighting device (10) according to one of the preceding claims, characterized in that the holder (200) has an opening (202) in the hotspot area (400) on a side of the diffuser (300) facing away from the light guide (100). Lighting device (10) according to one of the preceding claims, characterized in that an outer dimension of an assembly of lighter (100), holder (200) and diffuser (300) in the hotspot area (400) is the same as in the remaining area (600). Lighting device (10) according to one of the preceding claims, characterized in that the diffuser (300) has a homogeneous distribution of scattering centers (306). Vehicle (20) having a lighting device (10) according to one of the preceding claims. vehicle (20) after claim 9 , characterized in that the lighting device (10) is designed at least as interior lighting (11) or as exterior lighting (12).

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