Lighting device for illuminating the interior of a vehicle

Abstract

A lighting device for illuminating the interior of a vehicle is described. The lighting device comprises a light source (7b), a light collector (2) for capturing light from an external light source, and a light guide (7a) for transmitting the collected light from the light collector to the light source (7a), wherein the light guide (7a) is configured to couple the transmitted light into the light source (7a) so that the light coupled into the light source (7b) can exit through at least one light-emitting surface of the light source (7b) and illuminate the interior of the vehicle. A vehicle with a lighting device for illuminating the interior of the vehicle is also described.

Description

[0001] The present disclosure generally relates to lighting devices. More specifically, the present disclosure relates to a lighting device for illuminating an interior of a vehicle.

[0002] Lighting devices for illuminating vehicle interiors are known. Systems are also known in which LEDs are used as light sources to illuminate vehicle interiors or to provide ambient lighting in vehicle interiors.

[0003] After use, LEDs are combined with light guides, which can direct the LED light to the desired light emission points. Such systems are limited in their maximum brightness, particularly because the LED power in the interior cannot exceed a specified limit. Therefore, such lighting can be dimly or not at all noticeable, especially under direct sunlight.

[0004] Another approach involves combining a large number of LEDs into a strip, radiating the LEDs into a single light-emitting optic. To ensure homogeneous illumination, a sufficient distance must be maintained between the LED strip and the light-emitting surface, which is not always feasible due to the required installation space. Furthermore, these systems require energy-intensive and cost-intensive current control and heat dissipation measures for normal operation.

[0005] An object of the embodiments of the present disclosure is to provide a particularly energy-efficient lighting device for illuminating an interior of a vehicle.

[0006] To achieve this object, according to a first aspect, a lighting device for illuminating the interior of a vehicle is provided. The lighting device comprises a luminous element. The luminous element can, in particular, be designed to be arranged in the interior of the vehicle for interior or ambient lighting.

[0007] The lighting device also comprises a light collector for capturing or collecting light from an external light source, in particular natural sunlight.

[0008] The lighting device also includes a light guide for transmitting the collected light from the light collector to the luminous element. The light guide is designed to couple the transmitted light into the luminous element, so that the light coupled into the luminous element can exit through at least one light exit surface of the luminous element and illuminate the interior of the vehicle. In particular, the lighting device can be designed such that the light emerging from the luminous element creates a visually perceptible glow or ambient lighting in the interior of the vehicle.

[0009] The lighting device thus makes it possible to utilize sunlight for the vehicle's interior lighting, thereby reducing energy consumption and heat generation in the vehicle and increasing the vehicle's range. Due to the reduced heat generation, the prescribed power limits for interior lighting can also be more easily adhered to. Due to the optical coupling of the luminous element with the light collector, the amount or intensity of light emitted by the luminous element depends on the amount or intensity of light captured by the light collector. If, for example, the sunlight intensity decreases, the luminous intensity of the luminous element automatically decreases. The lighting device thus provides an automatic dimming function, or auto-dimming, in which the luminous intensity of the luminous element automatically adapts to the current ambient brightness.When ambient brightness decreases, dimming can occur automatically, especially without special sensors or active control, with the lighting intensity always being correctly proportional to the ambient brightness. This means that the light from the luminaire can be clearly perceived both in relatively dim ambient light and in bright daylight. Because the system captures the available ambient light and sunlight, the brightness of the ambient lighting is always adjusted to the environment and therefore has no or reduced glare compared to conventional systems without automatic dimming.

[0010] The lighting device can comprise one or more artificial light sources for generating artificial light for coupling into the luminous element. Thus, natural light, in particular sunlight, and artificial light can be combined in the luminous element, so that the luminous element can function as a common luminous element for both lights. The additional artificial or electrically operated light sources can ensure, in particular, that the luminous element can illuminate even on cloudy days or at night. The electrical light sources can at least partially replace the natural sunlight or ambient light.

[0011] The lighting device may comprise a light-concentrating body arranged downstream of the light collector for concentrating the light captured in the light collector. In particular, the light-concentrating body may be configured to concentrating the light before it enters the lighting body, thereby increasing the efficiency of converting sunlight into illumination light.

[0012] The light bundling body can comprise a first optical interface for coupling the light bundling body to the light collector and a second optical interface for coupling the light bundling body to one or more artificial light sources. The natural light from the light collector can reach the light bundling body via the first interface, and the artificial light can reach the light bundling body via the second interface. The light bundling body can be designed, in particular, as an optical mixing box in which the natural light and the artificial light are mixed to generate mixed light. The first and second interfaces can be designed substantially opposite a light output point of the light bundling body, such that the coupled-in light can reach the light output point with low loss.The light bundling body can in particular be funnel-shaped with a wide base facing the light collector, so that the natural light can easily enter the light bundling body.

[0013] The light collector can be designed to be mounted or integrated on or in the vehicle at an exposed or predominantly unshaded location. The light collector can in particular be configured to be mounted in an upper region of a door shoulder and / or on the instrument panel in the vehicle. In some embodiments, the light collector is designed to be arranged on or on the roof of the vehicle or to be integrated into the roof of the vehicle. The vehicle roof is normally exposed to sunlight during the day and also offers sufficient space for mounting the light collector. The orientation should preferably be such that the light collector is illuminated if the light output point is also illuminated externally.

[0014] The light collector can be designed as a vehicle design element, in particular as an exterior design element of the vehicle. In some embodiments, exposed design elements or decorative components of the vehicle are converted to accommodate light collectors or converted into solar collectors. The light collectors can be discreetly integrated into the vehicle environment, particularly camouflaged as decorative parts, even with a slight surface tint. Thus, solar collectors can be integrated into the vehicle without compromising the vehicle design.

[0015] In some embodiments, the luminous element comprises an elongated light guide with a light exit surface extending along the light guide. The luminous element can, in particular, be designed so that the luminous element can illuminate substantially over its entire length. Such a luminous element can, in particular, be used as a light bar for ambient lighting to illuminate the interior of the vehicle.

[0016] The lighting device can comprise a flat diffuser for scattering the light emerging from the at least one light exit surface. By scattering the emerging light, the homogeneity of the illumination of the luminous element can be increased.

[0017] In some embodiments, the lighting device comprises a color changer for coloring or modifying the spectral characteristics of the light generated by the lighting device. By means of the color changer, the sunlight captured in the light collector can be given a color or a spectral hue, so that a color design of the interior lighting can be enabled, for example, according to customer preference. In some embodiments, the color changer is designed in the form of an additional layer or color layer, which colors the sunlight before the light emerges from the luminaire. The color changer can, in particular, be arranged upstream and / or downstream of the diffuser. In some embodiments, the color layer is designed such that a color change can be realized by a mechanical displacement and / or rotation of the color layer.

[0018] According to a second aspect, a vehicle is provided. The vehicle has a lighting device for illuminating the interior according to the first aspect. The vehicle is characterized by high energy efficiency of the interior lighting and a correspondingly increased range.

[0019] The invention will now be explained in more detail with reference to the accompanying figures. The same reference numerals are used throughout the figures for identical or equivalent parts. Fig. 1 shows a schematic perspective view of a lighting device according to an embodiment, Fig. Figure 2 shows a schematic perspective view of the lighting device of the Fig. 1 in a first operating mode, Fig. Figure 3 shows a schematic perspective view of the lighting device of the Fig. 1 in a second operating mode, Fig. Figure 4 shows a schematic perspective view of the lighting device of the Fig. 1 in a third operating mode, Fig. 5 shows schematically a lateral cross-section through the light collector and the light bundling body according to Fig. 1 in the first operating mode, Fig. 6 shows schematically the lateral cross-section through the light collector and the light bundling body according to Fig. 1 in the second operating mode, and Fig. 7 shows schematically the lateral cross section through the light collector and the light bundling body according to a further embodiment.

[0020] Fig. 1 shows a schematic perspective view of a lighting device according to an embodiment for utilizing light, symbolically represented as light beam 1a, from the vehicle environment U for illuminating the vehicle interior.

[0021] The lighting device comprises a light collector 2 and a light condensing body 3, wherein the light condensing body 3 is coupled to the light collector 2 on the light input side via a light coupling interface. The light condensing body 3 is depicted as partially transparent in order to more clearly illustrate the area of ​​the light coupling interface.

[0022] The light coupling interface comprises a first interface 4a for coupling the natural light from the light collector 2 into the light bundling body 3 and a second interface 4b for coupling artificial light from an artificial light source into the light bundling body 3. In some embodiments, the light bundling body 3 comprises a light separator for separating the optical paths of the artificial and natural light. The light separator can be designed, in particular, as a double-sided reflective interface between the first interface 4a and the second interface 4b within the light bundling body 3. The light separator can, in particular, ensure that no or only a small amount of artificial light reaches the light collector 2 via the first interface 4a.

[0023] In the illustrated embodiment, the light collector 2 is designed in the form of a flat light guide. The light collector has a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface to the second main surface. A light exit boundary 5 is provided on the side surface. In this embodiment, the light exit boundary 5 is implemented in the form of a mirror coating on the side surface.

[0024] The lighting device further comprises a light guide 7a and a luminous element 7b, wherein the light-concentrating element 3 is optically coupled or connected to the luminous element 7b by means of the light guide 7a. The luminous element 7b is designed in the form of an elongated, clear light guide and has a light exit surface extending along the luminous element 7b and a rear-side mirror coating. The light guide 7a is optically coupled to one of the longitudinal ends of the luminous element 7b. The luminous element 7b can be designed, in particular, as a luminous element for interior lighting or ambient lighting of a vehicle. In the exemplary embodiment shown, a diffuser 8 is connected downstream of the luminous element 7b and extends essentially along the entire luminous element 7b.

[0025] The light collector 2 can comprise a plastic material with a high refractive index, such as Plexiglas or PMMA (polymethyl methacrylate). In some embodiments, the light collector 2 has depth-dependent refractive index gradients to promote or improve the light conduction properties of the light collector 2.

[0026] The light bundling body 3 is funnel-shaped or in the form of a truncated pyramid and has a wide base facing the light collector 2 and a light output point 6 opposite the wide base. The light bundling body is coupled to the light guide 7a via the light output point 6.

[0027] The light collector 2 can be arranged or mounted, in particular, in or on the vehicle at an exposed location, so that daylight can penetrate into the interior of the light collector 2 through the first and / or second main surface. Within the light collector 2, the sunlight can experience multiple reflections, in particular total internal reflections, at the first main surface, at the second main surface, and / or at the light exit boundary 5, whereby a portion of the captured light can penetrate into the light-concentrating body 3 via the broad base of the light-concentrating body 3.

[0028] Several reflections can also occur in the light-concentrating body 3, whereby a portion of the light can pass through the flat end of the light-concentrating body 3 into the light guide 7a and via the light guide 7a into the luminous element 7b. The light can exit the luminous element 7b through the light exit surface of the luminous element 7b and through the diffuser 8 as diffuse illumination light 9, which can be perceived as diffuse illumination in the interior of the vehicle.

[0029] Fig. Figure 2 shows a schematic perspective view of the lighting device of the Fig. 1 in a first operating mode. In the operating mode shown, or night mode, no sunlight is available, which is symbolically indicated by the crescent moon. Nevertheless, the lighting device can be used for interior lighting of the vehicle by activating the artificial light sources. The light provided by the artificial light sources can be coupled into the light bundling body 3 via the second interface 4b and reach the light guide 7a via the light output point 6. By means of the light guide 7a, the light can be guided into the luminous body 7b and cause the luminous body 7b to illuminate. Due to the downstream diffuser 8, a diffusely scattered artificial illumination light 9a is created.

[0030] Fig. Figure 3 shows a schematic perspective view of the lighting device of the Fig. 1 in a second operating mode. In this operating mode, both types of light, namely artificial light and natural light, are used. The natural light passes from the light collector 2 via the first interface 4a into the light bundling body 3, and the artificial light also passes into the light bundling body 3 via the second interface 4b. In the light bundling body 3, the two lights are bundled and guided to the light output point 6. From the light output point 6, the resulting mixed light is coupled into the light guide 7a and guided via the light guide 7a to the luminous body 7b, whereby the luminous body 7b is illuminated. This creates a combined illumination light 9b, which is composed of components of the natural and artificial light.

[0031] Fig. Figure 4 shows a schematic perspective view of the lighting device of the Fig. 1 in a third operating mode. In this operating mode, full sunlight occurs, in which the artificial light source no longer makes a significant contribution to the perception of luminance at the light emitting surface. The artificial light source can be switched off in this operating mode. Fig. The operating mode shown in Figure 4 thus corresponds to a pure daylight mode when only the external ambient light or daylight without additional energy sources is used to generate the light of the luminous element 7b.

[0032] Fig. 5 shows schematically a lateral cross-section through the light collector and the light bundling body according to Fig. 1 in the first operating mode. In the cross-sectional view of the Fig. 5, the interfaces 4a and 4b as well as the artificial light source 10 are better visible, wherein the power supply of the artificial light source 10 is symbolically represented as lines with plus and minus signs. The light source 10 is in the illustrated embodiment as an LED light source with a number of LEDs arranged in series, which are configured to couple the artificial light generated by the LEDs into the second interface 4b of the light bundling body 3. In the first operating mode, essentially only the artificial light is fed into the light bundling body 3 via the second interface 4b. This is shown in Fig. 5 using the exemplary light path 11. The second interface 4b can, in particular, have a number of recesses or depressions for accommodating LEDs. The LEDs can be aligned substantially in the direction of the light output interface 6 of the light bundling body 3, whereby the light loss within the light bundling body 3 can be reduced. In some embodiments, the light source 10 also has a narrow radiation characteristic, whereby the light output efficiency at the light output interface 6 of the light bundling body 3 can be further increased.

[0033] Fig. 6 shows schematically the lateral cross-section through the light collector and the light bundling body according to Fig. 1 in the second operating mode. In the second operating mode, both artificial light and natural light are used. Using an exemplary light path 12, the distribution of the natural light in the light collector 2 and in the light bundling body 3 is illustrated. Using another exemplary light path 11, the distribution of the artificial light from the second interface 4b to the light output point 6 is illustrated. As can be seen from the light paths 11 and 12, the two lights are mixed in the light bundling body 3, so that a mixed light reaches the light output point 6, which is then guided into the luminaire via the light guide 7a. In the diffuser 8, the light mixture is further homogenized, resulting in a diffuse, largely homogeneous combined illumination light 9b, cf. Fig. 3 above.

[0034] Fig. Figure 7 shows a schematic side cross-section through the light collector and the light bundling body according to a further embodiment. Fig. In the embodiment shown in FIG. 7, the side surface of the light collector 2 is at least partially translucent, so that the ambient light or sunlight can pass through the side surface into the light collector. The side surface can in particular have one or more areas without light exit limitation 5 or without mirroring, so that the ambient light can pass into the light collector 2. This is shown in FIG. Fig. 2 Illustrated using the exemplary light path 12.

[0035] In some embodiments, the lighting arrangement comprises a control device for controlling the artificial light source 10 so that the intensity of the artificial light can be adjusted as needed. During the day or under normal ambient brightness, the lighting device can largely operate without artificial light or provide sufficient illumination even without artificial lighting. In particular, the lighting device can comprise a sensor for detecting the current ambient brightness, and the control device can be configured to automatically adjust the power or light intensity of the artificial light source based on the current ambient brightness.

[0036] The lighting device can be designed to achieve perceptible interior lighting without activating the artificial light source, for example, when the ambient brightness exceeds a predefined level. Furthermore, the lighting device enables automatic dimming of the lighting, without an artificial light source. This is because the perceptibility of a light depends on the ambient brightness. If the ambient brightness decreases, the luminous intensity of the luminous element 7a decreases. At the same time, the subjective perceptibility of the light increases. In other words, the luminous intensity adapts automatically to the current ambient brightness, in particular without any electrical control.

[0037] The lighting device thus allows the external light potential or sunlight to be utilized for interior or ambient lighting in vehicle interiors. This allows sufficient and visually perceptible interior lighting to be achieved, depending on the ambient brightness, at low electrical power or even with artificial light completely switched off. The lighting device is thus characterized by particularly high energy efficiency, which reduces heat generation in the vehicle and increases the vehicle's range.

[0038] In some embodiments, the light collectors are designed to be clearly visible from the outside, in particular to clarify that an advanced environmentally friendly lighting technology is implemented in the vehicle.

[0039] The system can be used both as direct ambient light and as indirect lighting. For direct lighting, the light emitting surface is integrated so that it is directly visible. For indirect lighting, the light emitting surface or diffuser can be positioned so that it is hidden from direct view, illuminating a surrounding component in the vehicle's interior. The illuminated component can thus function as an indirect light source.

[0040] With the direct lighting variant, full-surface radiation or partial radiation at the exit surface can be implemented. With partial radiation, the light emission can be partially blocked by partially coating the surface. This allows for customized, predefined shapes or patterns of the exiting light to be realized.

[0041] The light guide 7a can be designed as a solid volume body and / or comprise a multitude of individual fiber optic strands that guide the light to the desired exit location. The latter option offers high flexibility, as individual fiber optic strands can be flexibly routed through small free spaces. Furthermore, with large distances between the light input and output surfaces, a design with lower mass can be achieved compared to the solid body concept.

[0042] By integrating a tinted layer through which the light passes before it exits, a customized color scheme can be achieved. This layer can, in particular, contain various tint colors that can be introduced into the optical path of the light by physical displacement and / or rotation. This allows a predefined illumination color to be selected according to customer requirements. In some embodiments, an OLED color filter is used as a color changer, allowing a broad color spectrum or color palette to be realized. Furthermore, the light-collecting surface itself can also be coated with a light tint to achieve a dark appearance as a decorative component without excessively compromising light-collecting performance. A tinted surface can also reduce or prevent the influence of feedback stray light.

[0043] In some embodiments, multiple light collectors are used to achieve high illumination intensity, particularly with natural light, even in cloudy conditions and during changing sun positions. The multiple light collectors can be installed at different locations on or in the vehicle and designed to direct the light to the same exit point or to the same luminaire. This can increase the availability of ambient lighting when the sun positions vary and when the direction of travel changes.

[0044] Although at least one exemplary embodiment has been shown in the foregoing description, various changes and modifications may be made. The recited embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing description provides those skilled in the art with a road map for implementing at least one exemplary embodiment; numerous changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the appended claims and their legal equivalents. Furthermore, multiple modules or multiple products may be connected together in accordance with the principles described herein to obtain additional functions. List of reference symbols 1 natural light source 1a light beam 2 light collectors 3 light bundling bodies 4a first interface 4b second interface 5 Light emission limitation 6 Light extraction point 7a Light guide 7b luminous element 8 Diffuser 9 Illumination light 9a artificial lighting light 9b combined illumination light 10 artificial light source 11 Light Path 12 Light Path U Vehicle environment

Claims

[1] Lighting device for illuminating an interior of a vehicle, comprising: - a luminous body (7b) - a light collector (2) for capturing light from an external light source, and - a light guide (7a) for forwarding the collected light from the light collector to the luminous element (7a), wherein the light guide (7a) is designed to couple the forwarded light into the luminous element (7a) so that the light coupled into the luminous element (7b) can exit through at least one light exit surface of the luminous element (7b) and illuminate the interior of the vehicle. [2] Lighting device according to claim 1, wherein the lighting device comprises one or more artificial light sources (10) for generating an artificial light for coupling into the luminous body (7b). [3] Lighting device according to claim 1 or 2, wherein the lighting device comprises a light bundling body (3) connected downstream of the light collector (2) for bundling the light captured in the light collector (2). [4] Lighting device according to claim 3, wherein the light bundling body (3) comprises a first optical interface (4a) for coupling the light bundling body (3) to the light collector (2) and a second optical interface (4b) for coupling the light bundling body (3) to one or more artificial light sources (10). [5] Lighting device according to one of the preceding claims, wherein the light collector (2) is designed to be mounted or integrated on or in the vehicle at an exposed location. [6] Lighting device according to claim 5, wherein the light collector (2) is designed as a vehicle design element. [7] Lighting device according to one of the preceding claims, wherein the luminous element (2) comprises an elongated light guide with a light exit surface extending along the light guide. [8] Lighting device according to one of the preceding claims, wherein the lighting device comprises a flat diffuser (8) for scattering the light emerging from the at least one light exit surface. [9] Lighting device according to one of the preceding claims, wherein the lighting device comprises a color changer for coloring the light generated by the lighting device. [10] A vehicle having an interior, the vehicle comprising a lighting device according to any one of the preceding claims for illuminating the interior.

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