EP3112742B1 - Lighting device for a motor vehicle with luminescent elements - Google Patents

Description

The invention relates to a lighting device for a motor vehicle according to the preamble of claim 1.

The use of luminescent materials in motor vehicles and headlights (e.g. fluorescent or phosphorescent light panels, license plate lighting, designer panel lighting, etc.) to achieve specific lighting and design effects is known per se.

the DE 102012018292 A1 discloses a motor vehicle in which one or more component surfaces visible from outside the motor vehicle are designed as fluorescent and / or phosphorescent luminous surfaces. The phosphorescent or fluorescent substances are either applied to the component surfaces or embedded in the component.

the DE 10338826 A1 discloses lights for a motor vehicle headlight with components as a carrier for luminescent pigments, the components not contributing to the lighting implementation of a lighting function, but only serving decorative purposes.

the DE 102004045221 A1 discloses an illumination device for a license plate, in which the number plate is illuminated with the aid of fluorescent light generated by fluorescent substances.

the EP 1577609 B1 discloses a vehicle headlight with a signaling device with a fluorescent coating, the surfaces of a light guide plate being provided with a fluorescent paint.

the DE 2361569 A1 discloses very generally the use of fluorescent, phosphorescent and reflective substances as an admixture to an injection-moldable plastic material in order to produce signaling and warning means as marking or identification of vehicles.

the DE 10 2013 007 856 A1 discloses a light guide body in the material of which by means of infrared or ultraviolet light materials that can be excited to fluorescence and / or phosphorescence can be present, and a lighting device with this light guide body.

It is an object of the invention to provide a lighting device with special lighting effects; In particular, it is an object of the invention to provide a lighting device in which the visual appearance remains constant after the actual light function has been deactivated (styling effect, afterglow) and with which an additional homogenization of the light exit is achieved.

This object is achieved by a lighting device as mentioned at the beginning, which according to the invention is characterized by the features from the characterizing part of claim 1.

In contrast to the prior art mentioned, in the invention the luminescent element, i.e. the light source or the additional optical unit, is a part inside the lighting device that is separated from the outside by the optically effective component and is therefore not directly visible from the outside. Because of this, thanks to the invention, the visual appearance continues to be the same after the light function has been deactivated. In other words, the appearance of the afterglow follows that of the actual light function of the lighting device, e.g. signal light (daytime running light or parking light) or low beam. The emitted (luminescence) light is further shaped or dispersed via the optically effective component or via the additional optical unit, which is why an additional homogenization of the exiting (luminescence) light is achieved.

In the prior art mentioned above, however, the appearance in the activated and deactivated state of the light function is different or not homogeneous because the luminescent material is not part of an optical element (light source such as a light guide or an LED; additional optical unit such as a reflector) and / or is directly visible to an outside observer.

According to the invention, a specified light signature is to be illuminated homogeneously and provided with a distinctive styling effect.

The term "optically effective component that homogenizes the light output" refers to a component that homogenizes the light output in such a way that when the light source is activated or when light is emitted by the luminescent pigments, after the light source has been deactivated, an area of the component is located behind the component Lighting device is not directly visible, ie a direct view of the area behind the component is denied. The “optically effective component” can, as described in more detail below, be, for example, an imaging lens, an intermediate lens or thick-wall optics; However, it can also be composed of several components (e.g. a lens system made up of several lenses) which, together, fulfill the light-homogenizing function. The optically effective component also has a light-shaping effect in order to correctly represent the required light function and to ensure the spatial visibility of light functions.

In order to show the afterglow effect on the basis of the light function of the lighting device (e.g. a signal light function), the light source is now at least partially provided with pigments made of at least one luminescent material. The luminescent material is expediently selected from a fluorescent material or a phosphorescent material. The terms "luminescence / luminescent", "phosphorescence / phosphorescent" and "fluorescence / fluorescent" as well as their functional principle, namely the emission of optical radiation during the transition from an excited state back to the ground state, are assumed to be well known. The fluorescence and the phosphorescence are special forms of the luminescence, whereby the fluorescence decays quickly, whereas the phosphorescence glows for a longer time. Representative examples of luminescent / phosphorescent materials are pigments 50101 (green, for high luminance), 50105 (green, low luminance but very small pigment size) and 50034 (blue) from Honeywell.

The expression "the pigments made of the at least one luminescent material have a signaling effect" as used herein means that the luminescence or the appearance of the afterglow follows that of the light function (eg signal light, low beam) after deactivation of the light function of the lighting device, ie that the appearance of the lighting device when the light function is activated and deactivated is preferably essentially the same for an outside observer. This depends on the choice of pigments and on their amount, a person skilled in the art being able to select appropriate pigments or luminescent materials and measure their amount on the basis of his specialist knowledge, his ability and with the help of simple routine experiments. The light distribution of lighting devices (for example a signal light such as a parking light or a daytime running light, low beam) is usually subject to legal requirements that are well known to those skilled in the art.

Through the choice of the luminescent material (also referred to herein as a luminophore or fluorescent substance), the color of the luminescence can furthermore be adapted in accordance with the position on the motor vehicle, and different color impressions can thereby be generated. The color range depends on the light function and is subject to legal requirements, e.g. the currently applicable ECE or SAE regulations. Direction indicators fulfill a signal light function and must be in the yellow area according to the currently applicable requirements, regardless of whether they are attached to the front of the vehicle, the rear of the vehicle or as a side marker light, e.g. on the exterior mirror. Tail lights, brake lights, rear fog lights and rear parking lights are in the red area, while daytime running lights, front position or clearance lights and front parking lights are in the white area according to the currently applicable regulations. The blue area is intended for emergency vehicles. As mentioned, the selection of suitable luminophores is within the knowledge of a person skilled in the art.

In certain developments, the pigments can comprise two or more different luminescent materials. For example, the respective materials can have a different excitation spectrum. For example, a material can be excited by light in the visible wavelength range and another material by light in the non-visible wavelength range to emit luminescence (fluorescence, phosphorescence). For example, a blue-light-emitting LED or a blue-light-emitting laser can target a reddish phosphor and a UV-LED a bluish phosphor.

According to the invention, the light source is designed as a light guide and the additional optical unit is designed as a reflector with a light-reflecting surface, the light guide at least partially comprising pigments made of at least one luminescent material. The pigments made from the at least one luminescent material advantageously have a signaling effect.

In these embodiments, it has proven to be advantageous in practice if the optically effective component is an intermediate lens or thick-walled optics. The construction, the configuration and the arrangement of an intermediate lens or a thick-wall optic are carried out according to principles well known to the relevant person skilled in the art.

The fulfillment of the lighting function (e.g. daytime running lights or parking lights) is achieved by means of a light guide. The light guide is typically rod-shaped with a light coupling surface on one end face and a light exit surface radiating transversely to the longitudinal axis. The light exit is achieved by a large number of deflecting prisms which are arranged opposite the light exit area on the outer surface of the light guide and which follow the direction of the longitudinal axis. A reflector is arranged behind the light guide, which captures the light which emerges from the light guide to the rear by means of its light-reflecting surface and guides it usefully forwards (i.e. in the optical beam direction).

According to the invention, the pigments made of the at least one luminescent material are embedded in the light guide at least in some areas. The light guide can be doped with the pigments during manufacture; for example, the light guide can be made from a pigment-doped light-conducting plastic material such as PMMA or polycarbonate.

The excitation / activation of the pigments for the emission of luminescence can take place in a further development by the light coupled into the light guide by a first light source and emitted by the light guide, ie the light is excited when the light function of the lighting device is activated.

The excitation / activation of the pigments for the emission of luminescence can thus take place actively by additional light sources. According to the invention, the lighting device therefore has at least one further light component which excites the pigments to emit luminescence. The light source can be, for example, an LED, but also a laser. According to the invention, the light component comprises at least one light source for visible light and at least one light source for invisible light, in particular UV light. The at least one light component is positioned on at least one end face of the light guide. Since the afterglow effect with luminescent substances decreases over time, it can be useful in a specific example to keep the afterglow effect longer than naturally given and in a time-controlled manner through active lighting by the additional light source with invisible light. The invention can also be used for special lighting effects when switched on. For example, when the motor vehicle is opened by means of a remote control, the light source for the invisible light can first be activated, which excites the luminescent layer of the lighting device to emit luminescence and in this way leads to a glow; A little later the lighting equipment (e.g. daytime running lights, parking lights) with the actual light function (e.g. light stick, reflector) is dimmed up.

The reflector preferably has light-homogenizing structures on its light-reflecting surface, preferably groove-shaped structures, in order to conceal the inhomogeneity of the light guide or the LED. In order to further homogenize the luminance or to enlarge the luminous area, an optically effective component is connected downstream of the light guide / LED in the optical beam direction, as described above.

The embedded pigments made of the at least one luminescent material have a signaling effect.

The light emitted by the lighting device according to the invention expediently forms the light distribution of a signal light, in particular a daytime running light or a marker light or a direction indicator, or a dipped beam and / or high beam, the light distribution of the respective lights, as mentioned above, being subject to legal requirements that are known to the person skilled in the art .

Another subject matter of the invention is a motor vehicle headlight which comprises at least one lighting device according to the invention as disclosed herein. Modern motor vehicle headlights often have several light modules that can take over individual light functions individually or in cooperation. These light modules are often arranged in close proximity to one another in a headlight housing.

The motor vehicle headlight is expediently constructed according to headlight construction principles known per se and comprises a housing with a light exit opening which is covered with a cover lens, the at least one lighting device (and possibly the other provided light modules) being arranged in the housing.

If the lighting device according to the invention is a signal lamp, it can for example be designed or arranged in such a way that it follows the lens aperture of a light module or certain design lines.

The motor vehicle headlight can, for example, have the shape of a headlight. The structure of a headlight is known to the person skilled in the art. Front headlights often include several light modules, e.g. a daytime running light unit, a low beam unit, a high beam unit, a direction indicator unit, etc. A headlight according to the invention therefore also comprises at least one lighting device according to the invention in addition to the light modules known per se. In another example, the motor vehicle headlight can be a rear light. The structure of a rear light is known to the person skilled in the art. Tail lights often include several light modules, for example a tail light unit, a brake light unit, a turn signal unit, etc. A rear light according to the invention therefore also comprises at least one lighting device according to the invention in addition to the light modules known per se.

• Fig. 1 einen Schnitt durch eine Ausführungsform einer Beleuchtungseinrichtung,
• Fig. 2 einen Schnitt durch eine weitere Ausführungsform einer Beleuchtungseinrichtung,
• Fig. 3 den Leuchteindruck der Beleuchtungseinrichtung aus Fig. 1 von vorne gesehen (Ansicht ohne Zwischenlichtscheibe),
• Fig. 4 eine erfindungsgemäße Anordnung mit einem Lichtleiter mit darin eingebetteten lumineszierenden Partikeln,
• Fig. 5a einen Schnitt durch Fig. 3 entlang der Linie A-A mit einer Detailansicht zur Anregung der Lumineszenz durch das Lichtleiterlicht,
• Fig. 5b einen Schnitt durch Fig. 3 entlang der Linie A-A mit einer Detailansicht zur Lumineszenz,
• Fig. 6a einen Schnitt durch ein nicht erfindungsgemäßes Beispiel für eine Beleuchtungseinrichtung mit Kollimatoroptik, mit einer Detailansicht zur Anregung der Lumineszenz durch die Kollimatoroptik, und
• Fig. 6b den Schnitt aus Fig. 6a mit einer Detailansicht zur Lumineszenz.

The invention is described in more detail below with the aid of non-limiting examples and the accompanying drawings, the drawings showing:

• Fig. 1 a section through an embodiment of a lighting device,
• Fig. 2 a section through a further embodiment of a lighting device,
• Fig. 3 the light impression of the lighting device Fig. 1 seen from the front (view without intermediate lens),
• Fig. 4 an arrangement according to the invention with a light guide with luminescent particles embedded therein,
• Figure 5a a cut through Fig. 3 along the line AA with a detailed view of the excitation of the luminescence by the light guide light,
• Figure 5b a cut through Fig. 3 along the line AA with a detailed view of the luminescence,
• Figure 6a a section through an example not according to the invention for an illumination device with collimator optics, with a detailed view of the excitation of the luminescence by the collimator optics, and
• Figure 6b the cut out Figure 6a with a detailed view of luminescence.

Fig. 1 shows a section through a lighting device, here a signal light 1 for a motor vehicle. The signal light 1 comprises an essentially rod-shaped light guide 20 and a reflector 10 arranged behind the light guide 20. The light-reflecting surface of the reflector 10 is covered with a luminescent layer 12. The luminescent layer 12 is composed of pigments from a luminescent material (or also several luminescent materials). In the example shown, the pigments are made from a phosphorescent material. The layer 12 can, however, also be composed of fluorescent pigments or of a mixture of several different luminescent (fluorescent and / or phosphorescent) materials / pigments. The signal light 1 furthermore has an intermediate light disk 30 connected downstream of the light guide 20 in the optical beam direction. The intermediate lens 30 is designed according to principles known per se and has a light-shaping effect, ensures the spatial visibility of signal light functions, homogenizes the luminance and prevents a direct view from the outside of the components behind it (light guide 20, reflector 10). The intermediate lens 30 can be clear or "milky".

The light exit from the light guide 20 is achieved by a large number of deflecting prisms 21 which are arranged opposite the light exit surface on the lateral surface of the light guide 20 and follow the direction of the longitudinal axis (see also Fig. 3 ). The reflector 10 guides the light which emerges from the light guide 20 to the rear, usefully forwards by means of its light-reflecting surface. The light emission cone 25 directed forwards in the beam direction from the light guide 20 and the light emission cone 24 from the light guide 20 backwards in the direction of the reflector 10 are shown in FIG Fig. 1 shown schematically. The light 24 from the light guide 20, represented by the light emission cone 24, excites the luminescent pigment layer 12 to emit luminescent light 15 (shown schematically by arrows 15).

The signal light 1 is arranged in a motor vehicle headlight which is constructed according to headlight construction principles known per se and comprises a housing with a light exit opening which is covered by a cover plate. In Fig. 1 only the cover plate 50 is shown schematically. In addition to the signal lamp of the known type, the motor vehicle headlight also has one or more light modules.

Fig. 2 shows a section through a further lighting device, here a signal light 2. The structure of the signal light 2 corresponds to the structure of the signal light from FIG Fig. 1 , with the only difference that, instead of an intermediate lens 30, it has thick-wall optics 40 connected downstream in the optical beam direction. The light 25 emitted by the light guide 20 is shaped and homogenized by the thick-walled optics 40. The thick-wall optics 40 is also designed according to principles known per se and has a light-shaping effect, ensures the spatial visibility of signal light functions, homogenizes the luminance and prevents the components behind it (light guide 20, reflector 10) from being viewed directly from the outside. In relation to everyone else Components of the signal light 2 (ie light guide 20, reflector 10, luminescent layer 12 etc.) is referred to the above description of the signal light 1 ( Fig. 1 ) referenced.

In Fig. 3 the light impression of the signal light 1 is off Fig. 1 Shown in front view and without intermediate lens 30. The light generated by a light source 22, for example a 450 nm laser diode or InGaN (indium gallium nitride) LEDs, enters an end face 26 of the essentially rod-shaped light guide 20 that follows a design line. The color emission of the light source 22 is matched to the corresponding signal light function. If the light source 22 is designed as a laser diode, then, in order to make the laser light usable for a motor vehicle lighting device, the laser light is used to irradiate a luminous element, a so-called phosphor converter, which is thereby stimulated to emit visible light; the phosphor converter is matched to the desired color of the signal light function. Various materials are known or are in use for this purpose. InGaN LEDs are available in blue, yellow, red or UV, for example. The light exit from the light guide 20 is achieved by a large number of deflecting prisms 21 ', which are arranged opposite the light exit surface on the outer surface of the light guide 20 and follow the direction of the longitudinal axis (the lines 21' symbolize the translucent edges of the deflecting prisms 21 that are visible from the front ). The light 24 emerging from the light guide 20 and striking the reflector 10 towards the rear strikes the luminescent layer 12 of phosphorescent pigments as described above, as a result of which the pigments are stimulated to emit luminescence 15 (phosphorescence). The reflector 10 also has light-homogenizing, groove-shaped structures 13 on its light-reflecting surface, which hide the inhomogeneity of the light guide 20.

Fig. 4 shows an embodiment according to the invention in which the luminescent pigments 11 are not applied as a luminescent layer on the reflector, as shown in the other figures, but are embedded in the light guide 20, which, as described, has a plurality of deflecting prisms 21. For this purpose, the light guide 20 is already doped with the luminescent pigments 11 during manufacture; For example, the light guide 20 can be made from a pigment-doped light-conducting plastic material such as PMMA or polycarbonate. The light guide 20 is, as in Fig. 2 shown, a thick-wall optics 40 connected downstream in the optical beam direction of the light emerging from the signal lamp. Are on or in the immediate vicinity of an end face of the light guide 20 Light sources 22 and 23 arranged. The light source 22 as the primary light source is, for example, a 450 nm laser diode or indium gallium nitride (InGaN) LEDs, the color emission of which is matched to the corresponding signal light function. The light sources 23 can be, for example, UV LEDs or 405 nm laser diodes (visible light in the blue wavelength range). If the light source 22 or the light sources 23 are designed as laser diodes, then in order to make the laser light usable for a motor vehicle lighting device, a light element, a so-called phosphor converter, is irradiated with the laser light Light is stimulated; the phosphor converter is matched to the desired color of the signal function. Various materials are known or are in use for this purpose. InGaN LEDs are available in blue, yellow, red or UV, for example. In this embodiment, the excitation / activation of the luminescent pigments 11, alternatively or in addition to the light source 22, is carried out by the light sources 23. By active illumination by the additional light sources with invisible UV light, for example, the afterglow effect can be sustained longer than natural and time-controlled become. When the signal light is switched on, this variant can also be used for special lighting effects. For example, when the motor vehicle is opened by means of a remote control, first the light source 23 for the invisible UV light or for the blue 405 nm light is activated, which excites the embedded pigments 11 to emit luminescence and in this way leads to a glow; a little later the signal light (daytime running lights, parking lights) with the actual light function is dimmed up for visible light by switching on the light source 22. In advantageous developments, the embedded pigments 11 can comprise two or more different luminescent materials. For example, the respective materials can have a different excitation spectrum. For example, a first material can be stimulated to emit luminescence (fluorescence, phosphorescence) by the light source 22, which emits light in the visible wavelength range, and a further material by the light sources 23, which can emit light in the non-visible wavelength range (e.g. UV) become.

Figure 5a shows a section through Fig. 3 along the line AA with a detailed view of the excitation of the luminescent layer 12, which is arranged on the reflector 10, by the light 24 emitted from the light guide 20 to the rear in the direction of the reflector 10 (see also description relating to FIG Fig. 1 and Fig. 3 ). The emitted Luminescence 15 is directed by means of reflector 10 in the beam direction of light 25 emerging from signal lamp 1.

Figure 5b shows a section through Fig. 3 along the line AA with a detailed view of the luminescence 15 which is emitted by the luminescent layer 12 after the actual signal light function brought about by the light guide 20 has been deactivated. In the specific example, the luminescent layer 12 is composed of pigments from a phosphorescent material, as mentioned above. Figure 5b therefore illustrates the “afterglow” visible to an outside observer due to the phosphorescence 15 emitted by the layer 12.

Figure 6a shows a section through an example not according to the invention for an illumination device 3 with collimator optics, with a detailed view of the excitation of the luminescence by the collimator optics. The lighting device 3 comprises, as primary optics, collimator optics with a light source 22a in the form of an LED for visible light and a collimator 60. The collimator 60 is constructed according to principles known per se and has a feed area 61 for the light emitted by the light source 22a, a light exit surface 63 as well as deflecting flank areas 62 at which the light is directed forward in the direction of the light exit surface 63. The primary emission after the light emerges from the primary optics (collimator optics) is identified by the reference symbol 66. A luminescent layer 12 of pigments made of a luminescent material (or also a plurality of luminescent materials) is applied to the deflecting flank regions 62 of the collimator 60. As an alternative to this, the pigments can also be embedded locally in the deflecting flank regions 62 (not shown). In the example shown, the pigments are made from a phosphorescent material. The layer 12 can, however, also be composed of fluorescent pigments or of a mixture of several different luminescent (fluorescent and / or phosphorescent) materials / pigments. The lighting device 3 also has an imaging lens 65 (secondary optics) connected downstream of the collimator optics (primary optics) in the optical beam direction. The imaging lens 65 prevents a direct view from the outside of the area behind and homogenizes the luminance or the light exit. In the case of further developments, the imaging lens can be provided in a manner known per se with additional means which further intensify the homogenization of the light exit, for example with microstructures. the Light distribution of the lighting device 3 is identified with the reference symbol 66 '. Instead of an individual imaging lens 65, a lens system (not shown) which fulfills the function of homogenizing the light exit can of course also be used as secondary optics. The excitation of the luminescent layer 12 to emit luminescence 15 is carried out by the light emitted by the light source 22a and deflected at the deflecting flank regions 62. The emitted luminescence 15 passes through the collimator 60 and the imaging lens 65 to the outside.

Figure 6b shows the cut Figure 6a with a detailed view with regard to the luminescence 15 which is emitted by the luminescent layer 12 after the deactivation of the light function brought about by the collimator optics (light source 22a, collimator 60). In the specific example, the luminescent layer 12 is composed of pigments from a phosphorescent material, as mentioned above. Figure 6b therefore illustrates the “afterglow” visible to an outside observer due to the phosphorescence 15 emitted by the layer 12.

Claims (9)

1. Lighting device for a motor vehicle, having at least one lighting shaping unit comprising a light source (20) realised as a light guide (20) and a supplemental optical unit (10), and having an optically active component (30, 40) being located downstream of the lighting shaping unit in the optical beam direction and homogenising the light output, the supplemental optical unit (10) being realised as a reflector (10) having a light-reflecting surface (14), wherein the reflector (10) directs the light which emerges rearwards from the light guide (20) forwards by means of its light-reflecting surface (14), the light guide (20) comprises, at least partially, pigments (11) of at least one luminescent material which are embedded in the light guide (20), at least in regions thereof, and when the light function of the illumination device is activated the pigments (11) are excited by means of the light (24) coupled into the light guide (20) by a first light source (22) and emitted through the light guide (20), to emit luminescence light (15),
   characterised by at least one further light component (23) which excites the pigments to emit luminescence light when the light function of the illumination device is deactivated, the at least one further light component (23) being positioned on at least one front face (26) of the light guide (20) and comprising at least one light source for visible light (23) and at least one light source (23) for non-visible light, and wherein the pigments have a signalling effect, the signalling effect having the appearance of an afterglow which follows the appearance of the light function after deactivation of the light function of the illumination device.
2. Lighting device according to claim 1, characterised in that the luminescent material is selected from a fluorescent material or a phosphorescent material.
3. Lighting device according to claim 1 or 2, characterised in that the pigments (11) comprise two or more different luminescent materials.
4. Lighting device according to one of claims 1 to 3, characterised in that the optically effective component is an intermediate light pane (30) or a thick-walled optical system (40).
5. Lighting device according to one of the claims 1 to 4, characterised in that the at least one light source (23) for non-visible light of the light component (23) is a UV light.
6. Lighting device according to one of claims 1 to 5, characterised in that the reflector (10) has groove-like structures (13) on its light-reflecting surface (14).
7. Lighting device according to one of claims 1 to 6, characterised in that the light emitted by it forms the light distribution of a signal light, in particular a daytime running light or a limiting light or a direction indicator, or a dipped beam and/or main beam.
8. Motor vehicle headlamp comprising at least one lighting device according to any one of claims 1 to 7.
9. Motor vehicle headlamp according to claim 8, characterised in that it comprises a housing with a light emission opening covered by a cover lens (50), the at least one lighting device being arranged within the housing.

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