EP3341647B1 - Light module for vehicle headlight - Google Patents

Description

The invention relates to a light module for a vehicle headlight or a vehicle lamp comprising at least one primary light source, which is designed as an elongated luminous element and is designed to generate at least one primary light beam, at least one secondary light source, which secondary light source comprises at least one first layer, which layer is set up to emit light, and at least one second layer, which has at least one reflecting surface, which reflecting surface is set up to reflect at least the light emitted by the first layer, the at least one Secondary light source emits the at least one primary light beam to at least one secondary light beam in such a way that the light module emits light to form a light distribution of a predetermined type, and the at least one secondary light source as a flat, planar Li is formed, and wherein the light reflecting surface is arranged such that it deflects the at least one primary light beam.

Furthermore, the invention relates to a motor vehicle headlight and / or a motor vehicle rear light with at least one such light module.

Organic light-emitting diodes (OLEDs) are particularly suitable for use as a signal light function due to their homogeneous emission characteristics, the low installation depth, the almost arbitrary shape and the possibility of segmentation. In addition, these illuminants enable the implementation of customer-specific design requests with regard to special lighting impressions and to display depth effects. However, due to the low luminance of the OLEDs, the light values (values of the light intensity), which are required for e.g. direction indicators (FRA for short), daytime running lights (TFL for short), rear lights (brake lights, tail lights, rear fog lights, reversing lights) or side marker lights, cannot currently be achieved. This problem is particularly evident when the OLEDs are used in the front area of the vehicle, since, for example, correspondingly high luminous intensity values can be achieved in the direction of travel (HV measuring point).

Both the FMVSS and the ECE standards require significantly lower light values in the edge area of the light distribution than in the center. The lower light values in the edge area can already be achieved at the present time thanks to the Lambert radiation pattern of the OLED despite the low luminance. However, the higher light values in the central measuring points cannot be achieved without switching on additional light sources.

One way to counter the above problem is at least partially (see e.g. WO 2011107904 A1 ) to attach additional light sources, such as LEDs with front optics, near an OLED having a predetermined shape. The use of LEDs, however, affects the homogeneity of the radiation. In addition, the OLED must have a certain shape, which limits the use of such light modules in, for example, headlights for reasons of installation space and design.

The object of the invention is to remedy the shortcomings of the light modules according to the prior art and to provide a light module suitable for vehicle headlights. This object is achieved according to the invention with a light module mentioned at the outset in that the at least one primary light source is designed as a light rod, the light rod having a multiplicity of deflection prisms, which deflection prisms are set up to transmit the light, which light to the at least one primary light source. Beam of light forms to couple out of the light stick and to direct it in the direction of the secondary light source.

In some cases, it can advantageously be provided that the primary light source emits light in a first spectral range and the first layer emits light in a second spectral range, the first spectral range at least partially superimposing the second spectral range.

In other cases, it can be particularly advantageous if the primary light source emits light in a first spectral range and the first layer emits light in a second spectral range, the first spectral range not superimposing the second spectral range. This can be advantageous if the reflecting surface is intended to reflect the light emitted by the first layer but to transmit the light generated by the primary light source.

With regard to the formation of the secondary light beam, it is provided according to the invention that the light-reflecting surface is arranged such that it deflects the at least one primary light beam.

In order to take account of the homogeneity requirement, it can be expedient if the at least one primary light beam irradiates essentially the entire reflecting surface.

With regard to the possible design of the light module, it is provided according to the invention that the at least one secondary light source or the first layer as an areal, i.e. is formed over a surface extending light source.

This embodiment is also particularly advantageous because, with a planar secondary light source, design requirements (for example, according to a large-area, homogeneous lighting impression) and legal standards can be taken into account (with the aid of the primary light source).

In addition, it is provided according to the invention that the at least one secondary light source (2) or the first layer is designed as a planar, planar light source.

With regard to the desired design, it can be advantageous if the at least one secondary light source is designed as a planar curved light source. This alternative is outside the scope of the claims.

In general, it should be noted that a homogeneous surface lighting impression can be awakened with both flat and curved secondary light sources. A curvature of the secondary light source will, for example, not lead to collimation of the radiation generated by the secondary light source. However, since this is of secondary importance for the fulfillment of the FRA and / or TFL light values, the shape of the secondary light source can serve, for example, decorative design purposes.

With regard to the possible uses in a motor vehicle headlight, it can be advantageous if the specified type of light distribution is a direction indicator or a daytime running light.

In addition, it can be provided that the specified type of light distribution is a tail light and / or a brake light. The light module can be used in a tail / brake light if the light module is arranged in a signal light in a rear area of a vehicle.

It can also be provided that the first layer is formed in one piece with the second layer. The secondary light source is in one piece, e.g. as an OLED, trained and offers the advantage in terms of installation space.

Furthermore, it can be provided that the first layer has two or more light-emitting segments and the two or more light-emitting segments can be controlled independently of one another. "Controllable" is to be understood here primarily as switching on and off. In addition, this can also be understood to mean the dimming (change in the intensity of the emitted light) of the segments. In this context, “independently of one another” is to be understood to mean that in fact all segments can be controlled independently of one another or that the segments can be controlled in groups independently of one another.

This allows different lighting effects, such as a "wiping direction indicator", which will be explained in more detail below.

With regard to various light settings, it can be expedient if each of the two or more light-emitting segments emits light in a predetermined spectral range. Each segment can emit light in a different color and light productions such as "Coming Home" and / or "Leaving Home" can be realized.

It can also be advantageous if the second layer has two or more light-reflecting segments.

With regard to the manufacture, it can be advantageous if the number of light-emitting segments is equal to the number of light-reflecting segments and each light-emitting segment is formed in one piece with a light-reflecting segment.

In order to implement different lighting functions and lighting scenarios, it can be useful if a control unit is assigned to the light module, which control unit is set up to control the at least one primary light source and the at least one secondary light source.

With regard to the service life, it can be particularly advantageous if the first layer is assigned an opaque element, which opaque element is arranged to protect the second layer from light of a certain wavelength, in particular UV light.

Furthermore, it is provided according to the invention that the at least one primary light source is designed as a light stick.

With regard to the supplementation of the light emitted by the secondary light source by a primary light beam, it is provided according to the invention that the light bar has a plurality of deflection prisms, which deflection prisms are set up to transmit the light which forms the at least one primary light beam, decouple from the glow stick and steer towards the secondary light source.

In a preferred embodiment of the invention, it can advantageously be provided that the at least one secondary light source is designed as an OLED, the first layer being designed as an emitter layer of the OLED and the second layer as a cathode of the OLED having a reflective surface .

In addition, it can be provided that the first layer is designed as a transparent OLED and the second layer as at least one light deflection element.

Furthermore, it can be advantageous if the at least one secondary light source is designed as an OLED, the first layer being designed as an emitter layer of the OLED and the second layer being designed as a cathode of the OLED, the cathode facing one toward the emitter layer Has essentially light-reflecting surface and a substantially transparent surface facing away from the emitter layer. In addition, it can be advantageous if the at least one OLED is curved.

• Fig. 1 eine organische Leuchtdiode (OLED - organic light emitting diode) nach dem Stand der Technik,
• Fig. 2 die wesentlichen Komponenten einer bevorzugten Ausführungsform eines erfindungsgemäßen Lichtmoduls und deren Zusammenhang in schematischer Darstellung,
• Fig. 3 die wesentlichen Komponenten einer Ausführungsform mit einer halbtransparenten OLED eines Lichtmoduls und deren Zusammenhang in schematischer Darstellung, die nicht unter den Schutzumfang der Ansprüche fällt,
• Fig. 4 die wesentlichen Komponenten einer bevorzugten Ausführungsform mit einer transparenten OLED eines erfindungsgemäßen Lichtmoduls und deren Zusammenhang in schematischer Darstellung,
• Fig. 5 ein als eine Signalleuchte ausgebildetes erfindungsgemäßes Lichtmodul,
• Fig. 6 einen Querschnitt entlang der Linie AA' der Fig. 5, und
• Fig. 7 eine weitere mehrere OLEDs aufweisende Ausführungsform eines erfindungsmäßen Lichtmoduls.

The invention and further advantages are explained in more detail below using exemplary embodiments which are illustrated in the drawing. In this shows

• Fig. 1 an organic light emitting diode (OLED) according to the prior art,
• Fig. 2 the essential components of a preferred embodiment of a light module according to the invention and their relationship in a schematic representation,
• Fig. 3 the essential components of an embodiment with a semi-transparent OLED of a light module and their relationship in a schematic representation, which does not fall under the scope of the claims,
• Fig. 4 the essential components of a preferred embodiment with a transparent OLED of a light module according to the invention and their relationship in a schematic representation,
• Fig. 5 a light module according to the invention designed as a signal light,
• Fig. 6 a cross section along the line AA 'of Fig. 5 , and
• Fig. 7 a further embodiment of a light module according to the invention having several OLEDs.

First up Fig. 1 Referred. This shows a conventional OLED 1, which is made up of several layers. An OLED has an anode 50, a hole line layer 40, an emitter layer (emission layer) 30, an electron line layer 20 and a cathode 10. The anode 50, which mostly consists of indium tin oxide, is usually located on a substrate 55, which can be designed as a glass plate or a PET film. The hole line layer 40 is applied to the anode 50. A further layer, not shown here, can be applied between the anode 50 and the hole conduction layer 40, which layer for Lowering the injection barrier for holes serves and prevents indium from diffusing into the transition. The emitter layer 30 is applied to the hole line layer 40 and normally contains between 5% and 10% phosphor (dye). Less often, the emitter layer 30 consists entirely of the dye. Optionally, an electron conduction layer 20 is applied between the emitter layer 30 and the cathode 10, which consists, for example, of a metal or an alloy with a low electron work function. As a protective layer and to reduce the injection barrier for electrons, a very thin layer (made of lithium fluoride, cesium fluoride or silver), not shown here, can be evaporated between the cathode 10 and the electron conduction layer 20 or emitter layer 30.

The electrons (i.e. the negative charge carriers) are now injected from the cathode 10 while the anode 50 provides the holes (i.e. the positive charge carriers). Electrons and holes drift towards one another, favored by a voltage U applied between the anode and cathode, and ideally meet in the emitter layer 30, which is why this layer is also called the recombination layer. Electrons and holes form a bound state, which is called an exciton. Depending on the mechanism, the exciton already represents the excited state of the dye molecules (phosphor molecules) forming the emitter layer, or the decay of the exciton provides the energy to excite these dye molecules. The dye (phosphor) has different states of excitation. The excited state can change to the ground state and emit a photon (light particle). The color of the emitted light depends on the energy gap between the excited and the ground state and can be changed in a targeted manner by varying the dye molecules. The use of phosphors is known in which the light is emitted both from singlet states (fluorescence) and from triplet states (phosphorescence). Depending on the nature of the cathode material, OLEDs can emit light in one or both of the directions L1, L2 shown. In the case of a reflective (for example a metallic) cathode 10, this can be used as a reflector for light that is not generated by the emitter layer 30.

An example preferred embodiment of the present invention in Fig. 2 shows a light module which comprises a primary light source 110 and a secondary light source 2, the secondary light source 2 as OLED with one as emitter layer 30 formed first layer and a second layer formed as a light reflecting (for example a metallic) cathode 10. The primary light source 110 is designed as a light bar, which has deflection prisms (defects) 111 for coupling out the light from the light bar 110.

In connection with the present invention, the term "light stick" is understood to mean a light guide, which light guide has one, two or more light sources, e.g. Light-emitting diodes (LEDs) are assigned, the light source / light sources being arranged on at least one end face of the light guide and through which at least one end face the light from the light source (s) is fed into the light guide. The light is usually inside on the boundary walls of the circular, but possibly also another, e.g. elliptical, cross-section light guide totally reflected, but at the defects that e.g. are prism-shaped as deflection surfaces, deflected and radiated essentially on the side opposite to the defects. The contour and the geometry of the light sticks in automotive construction are often determined by design specifications, whereby the desired contours can often no longer be achieved with a single light stick and in many cases it is necessary to fork a light stick in two branches.

A primary light beam 210 is formed by decoupling the light from the light rod 110, the deflection prisms 111 being arranged such that the primary light beam 210 illuminates the emitter layer 30 and strikes the reflective surface 10r of the cathode 10, the primary Light beam 210 preferably illuminates the entire reflective surface 10r. The primary light beam 210 reflected by the reflecting surface 10r penetrates the emitter layer 30 again and supplements the light 200 emitted by the emitter layer to form a secondary light beam 220. Light 220 is emitted to form a light distribution of a certain type, so that the light module according to the invention in one or more of the following vehicle lights can be used: direction indicators (both in the front and rear areas of the vehicle), daytime running lights, tail lights, brake lights, rear fog lights, reversing lights, and side marker lights. In addition, it is preferably provided that the secondary light beam 220 has sufficient intensity (light intensity) so that the light module according to the invention emits the amount of light required by law for the above-mentioned vehicle lights. This has the advantage that, for example, those mentioned above Vehicle lights the insertion of the light module according to the invention is sufficient and no further light modules / light sources / luminous elements or the like. are necessary.

Another embodiment of a light module with a semi-transparent OLED 1h based on its essential components is shown in Fig. 3 illustrated. This embodiment is not within the scope of the claims. The term "semi-transparent" refers to the properties of the cathode 10, which is designed such that a reflecting surface 10r of the cathode 10 facing the emitter layer 30 largely reflects the light emitted by the emitter layer 30 and a surface facing away from the emitter layer 30 10t of the cathode 10 essentially transmits the primary light beam 210. The primary light source, which in turn is designed as a light rod 110, is arranged such that essentially all of the light from the primary light beam 210 shines through the surface 10t facing away from the emitter layer 30 and supplements the light generated by the emitter layer 30. A secondary light beam 220 is generated, which can be used to form a light distribution of a certain type.

At this point it should be noted that the light stick and the OLED (or several OLEDs ( Fig. 7 )) Can emit light in different colors. The term "color" is understood to mean light from a specific predetermined spectral range (or several spectral ranges).

In the in Figures 2 and 3rd In the illustrated embodiments, the first light-emitting layer (emitter layer 30) is formed in one piece with the second layer (cathode 10) of the secondary light source 2 which has a surface 10r suitable for reflecting the light emitted by the emitter layer 30. Fig. 3 3 schematically illustrates an embodiment in which the light bar 110 is arranged such that the primary light beam 210 is directed essentially parallel to the light 200 emitted by the emitter layer. The formation of the secondary light beam 220 is made possible by a special coating of the cathode 10 of the secondary light source 2, which is designed here as an OLED 1h. In addition, it should be noted that the surface 10r facing the emitter layer 30, like the surface 10t facing away from the emitter layer 30, is transparent to the primary light beam 210. A cathode with such properties can be achieved, for example, by a special coating on the cathode, which coating has to be adapted to the spectral properties of the light stick and / or the OLEDs (OLEDs). For example, it is quite possible To use coating that reflects the light emitted by the emitter layer and transmits the primary light beam generated by the glow stick.

At another in Fig. 4 In the illustrated embodiment, the secondary light source 2 comprises a first layer 1t and a second layer 10 ', the first layer 1t being formed separately from the second layer 10'. The first layer 1t is designed as a transparent OLED. This transparent OLED 1t comprises a light-emitting emitter layer 30 and a cathode 10, which has a transparent surface 10t. Because the cathode 10 is designed to be translucent, the OLED 1t emits light in (essentially) two directions L1, L2. The second light-reflecting layer can be designed as a reflector 10 ′, which is arranged and designed such that the light emitted by the OLED 1t in the second direction L2 is reflected in the first direction L1. A primary light source designed as a light rod 110 is arranged such that the primary light beam 210 is also deflected via the reflector 10 ′ in the first direction L1, that is to say to the transparent OLED 1t, and the light emitted by the OLED 1t a secondary light beam 220 added. The secondary light beam 220 is emitted to form a light distribution in the first direction L1, preferably in front of the light module. In general, the reflector 10 ′ used here can be replaced by an arrangement of light-deflecting optical elements which are suitable for directing the light emitted by the emitter layer 30 and the primary light beam 210 in the first direction L1. Such light-deflecting optical elements can be designed, for example, as prisms, in particular prisms having reflective surfaces. It is also conceivable to use a combination of prisms and reflectors.

After the operation of the most important components of the invention and their connection has been explained above, reference is now made to the 5 to 7 Referred. The Fig. 5 shows a light module of the Fig. 1 , which is designed as a signal lamp 100. The primary light source is designed as a light rod 110, which comprises a light source 112 (in particular an LED) and a light guide having a plurality of deflection prisms 111. The light from the light source 112 is fed into one end of the light guide and, as already explained, propagates in the light guide due to several total reflections. The deflection prisms 111 serve the purpose of coupling light out of the light guide. The light coupled out by means of the deflection prisms 111 forms the primary light beam 210, which is directed onto the OLED 105 arranged in a holder 121 at a distance from the light bar 110 is directed. The holder 121 has a cover plate 120 and a spacer 122. The spacer 122 guarantees an exact positioning of the light guide with respect to the OLED and to the direction of radiation in relation to the vehicle (direction L1). The cover plate can serve, for example, as a support for a protective film and / or a protective glass, in particular for UV protection, since the OLEDs can often be sensitive to water and / or water vapor and / or UV light. The Fig. 6 represents a cross section of the Fig. 5 and discusses the beam path in the light module of the Fig. 5 . The primary light beam 210 directed onto the OLED 105 is reflected by the reflecting surface 10r of the cathode 10 and supplements the light generated by the emitter layer 30 of the OLED 105. The secondary light beam 220, which propagates in the direction L1, comprises three essential components. First, the reflected primary light beam 210 of the light stick 110 contributes to the formation of light. Secondly, part of the light generated by the emitter layer 30 is emitted in the direction L1. Thirdly, a further part of the light generated by the emitter layer 30 is deflected by the cathode 10 in the direction L1.

It should be noted at this point that the light module can comprise several OLEDs. An example of a light module with multiple OLEDs 105a to 105f is shown in FIG Fig. 7 shown schematically. It is advantageous to arrange the deflection prisms 111 of the light stick 110 such that the light stick 110 generates a plurality of primary light beams 210a to 210f, each primary light beam being directed onto the corresponding OLED and the entire surface of the OLED being illuminated.

With a light module according to the invention 5 to 7 a "wiping direction indicator" can be realized. Initially, only the OLED or OLEDs are put into operation (for example the first 200 milliseconds). The light stick is then switched on in order to supplement the light emitted by the OLED or the OLEDs and to generate a secondary light beam or secondary light beams which is or are suitable for forming a light distribution which complies with the legal standards are.

In addition, the use of multicolored OLEDs can not only be used to produce white light, but also various lighting scenarios (eg "coming home", "leaving home") and luminaires with depth effects.

As mentioned briefly above, the light module according to the invention can be used both in headlights and in rear lights and / or side marker lights of a vehicle. So e.g. When used in a rear light, the OLED can produce a tail light light distribution and the light stick (thanks to its high luminosity) can produce a brake light light distribution. It is important here that the light intensity (light intensity) of the secondary light beam 220 is always sufficient to form a light distribution of a certain type, regardless of the specific embodiment explained above. In the case and depending on the type of light distribution, the light module according to the invention can be used in one or more of the following vehicle lights: direction indicators (both in the front area and in the rear area of the vehicle), daytime running lights, tail lights, brake lights, rear fog lights, reversing lights, and side marker lights. One of the advantages of this is that e.g. in the case of the vehicle lights mentioned above, the use of the light module according to the invention is sufficient and no further light modules / light sources / luminous elements or the like. are necessary.

Claims (15)

1. Light module for a vehicle headlamp or a vehicle position light, comprising

   - at least one primary light source (110), which is designed as an elongated lighting device and is designed to generate at least one primary light beam (210),

   - at least one secondary light source (2), which secondary light source comprises

   • at least one first layer (30), which layer is set up to emit light, and

   • at least one second layer (10, 10'), which has at least one reflective surface (10r, 10'), which reflective surface (10r, 10') is designed to reflect at least the light emitted by the first layer (30),

   wherein the light emitted by the at least one secondary light source (2) complements the at least one primary light beam (210), resulting in at least one secondary light beam (220), in such a way that the light module radiates light to form a light distribution of a predefined type, and wherein the at least one secondary light source (2), i.e. the first layer (30), is designed as a planar, flat light source, wherein the light-reflecting surface (10r, 10') is arranged in such a way that it deflects the at least one primary light beam (210),
   characterized in that

   - the at least one primary light source (110) is designed as a light rod, wherein the light rod (110) has a plurality of deflecting prisms (111), which deflecting prisms (111) are designed to separate the light that forms the at least one primary light beam (210) from the light rod and to direct said light in the direction of the secondary light source (2), i.e. in the direction of the second layer (10').
2. The light module according to Claim 1, characterized in that the primary light source (110) emits light in a first spectral range and the first layer (30, 1t) emits light in a second spectral range, wherein the first spectral range at least partially overlaps the second spectral range.
3. The light module according to Claim 1, characterized in that the primary light source (110) emits light in a first spectral range and the first layer (30, 1t) emits light in a second spectral range, wherein the first spectral range does not overlap the second spectral range.
4. The light module according to any one of Claims 1 to 3, characterized in that the at least one primary light beam (210) essentially irradiates the entire reflective surface (10r).
5. The light module according to any one of Claims 1 to 4, characterized in that the predefined type of light distribution is a direction-indicator light distribution (FRA) or a daytime running-light light distribution (TFL) or a rear position-light light distribution or a brake-light light distribution or a rear fog-light light distribution or a reversing-light light distribution or a side-marker-light light distribution.
6. The light module according to any one of Claims 1 to 5, characterized in that the first layer (30) and the second layer (10) together form a single unit.
7. The light module according to any one of Claims 1 to 6, characterized in that the first layer (30) has two or more light-emitting, preferably independently controllable segments (105a to 105f), wherein preferably each of the two or more light-emitting segments (105a to 105f) emit light in a predefined spectral range.
8. The light module according to any one of Claims 1 to 7, characterized in that the second layer has two or more light-reflecting segments.
9. The light module according to Claims 7 and 8, characterized in that the number of light-emitting segments is equal to the number of light-reflecting segments and that each light-emitting segment is designed to form a single unit with a light-reflecting segment.
10. The light module according to any one of Claims 1 to 9, characterized in that the light module is associated with a control unit, which control unit is designed to control the at least one primary light source (110) and the at least one secondary light source (2).
11. The light module according to any one of Claims 1 to 10, characterized in that the at least one secondary light source (2) is designed as an OLED (1,105), wherein the first layer (30) is designed as an emitter layer of the OLED (1,105) and the second layer (10) as a cathode of the OLED (1, 105) having a reflective area (10r).
12. The light module according to any one of Claims 1 to 10, characterized in that the first layer (30) is designed as a transparent OLED and the second layer as at least one light light-deflecting element (10').
13. The light module according to any one of Claims 1 to 10, characterized in that the at least one secondary light source is designed as an OLED (1h), wherein the first layer is designed as an emitter layer (30) of the OLED (1h) and the second layer as a cathode (10) of the OLED (1h), wherein the cathode (10) has an essentially light-reflecting surface (10r) facing toward the emitter layer (30) and an essentially translucent surface (10t) facing away from the emitter layer (30).
14. A motor vehicle headlamp with at least one light module according to any one of Claims 1 to 13.
15. A motor vehicle rear-position lamp with at least one light module according to any one of Claims 1 to 13.

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