DE102020201644A1 - Lighting device for a motor vehicle - Google Patents

Abstract

The invention relates to a lighting device for a motor vehicle (K), with at least one light module (1), which has a light body (30) and at least one illuminant (51), the light rays (L) of which into a surface of the light body (30) serving as a light coupling surface ) can be coupled in or can be coupled in. The coupled-in light beams (L) can exit through a light exit surface surrounded by side surfaces (31-34) of the light body (30) towards the outside in the direction of a light emission direction of the lighting device Surface is one of the side surfaces (31-34) of the light body (30). A rear surface opposite the light exit surface and at least one of the side surfaces (31-33) have a reflective or diffuse backscattering coating (12), the coating (12) of the at least one side surface (31-33) as an integral part of the side surface (31-33) molded optical structure (10a, 10b, 10c) is formed.

Description

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

Such a lighting device is for example in the DE 10 2011 110 630 A1 described. In the case of the lighting device, light from light-emitting diodes is coupled into a light body made of milky acrylic glass, distributed in it and coupled out in the direction of a transparent lens.

From the DE 10 2011 110 629 A1 a lighting device for a motor vehicle is known in which light from light emitting diodes is initially coupled into a transparent, elongated light guide and from this in turn is coupled into an opaque, milky light body. The opaque light body decouples the light rays diffusely.

From the DE 198 60 697 A1 a light module has become known. Specifically, the light module has an optical waveguide with a light exit surface. A light-reflecting or diffusely backscattering film is arranged on the surface of the light module opposite the light outlet surface and on the side surfaces of the optical waveguide connecting the light outlet surface and the opposite surface. Furthermore, a light source for the lateral coupling of light is present on one of the side surfaces. At the light exit surface of the optical waveguide, the surface is provided with alternating light-scattering and flat surfaces. The area ratio of the flat surfaces to the light-scattering surfaces is selected as a function of the luminance at the respective location of the optical waveguide. The application of the reflective film is practically combined with the production of the optical waveguide, which is produced by injection molding. During production, the injection mold is previously covered with the film on the bottom surface and at least part of the side surface. When the plastic hardens after injection molding, the film adheres to the optical waveguide.

In the DE 199 02 774 A1 Finally, a luminous body with light-emitting diodes for backlighting information elements is described. The light-emitting diodes are used to introduce light into the interior of a hollow body, which has a light-emitting surface for backlighting the information elements. Opposite the light-emitting surface, a rear wall is formed, which is also formed to be light-emitting, self-luminous or simply opaque. Both surfaces are connected to one another by opaque or diffusely reflective side walls. The side walls have light entry openings in which light-emitting diodes or ends of light guides are arranged so that they can feed their light completely into the cavity. The opaque wall of the side surfaces consists of a material that is reflective with a high degree of reflection. The light exit surface and the opposite surface are made of light-scattering material with a low degree of absorption.

Furthermore, it should be mentioned that in the production of motor vehicle lighting devices, for reasons of space and to achieve certain optical effects, the use of flat OLED lamps (OLED = organic light-emitting diode) is often considered. However, OLED lamps are expensive and, due to their organic structure, have disadvantages with regard to their resistance to aging and robustness.

The present invention is therefore based on the object of providing a lighting device for a motor vehicle with which the use of OLED lighting means can be modeled optically and which is constructed in a space-saving and cost-effective manner.

The above object is achieved by a lighting device with the features of claim 1. Advantageous designs or further developments of the invention can be found in the dependent claims.

The invention is based on a lighting device for a motor vehicle, with at least one light module which has a light body and at least one illuminant. The light beams of the illuminant can be coupled into a surface of the light body serving as a light coupling surface or are coupled into it, the light beams being able to exit or exit via a light exit surface surrounded by side surfaces of the light body to the outside in the direction of a light emission direction of the lighting device

The lighting means can be designed as a monochrome LED (LED = light-emitting diode) that emits light, or as an RGB LED for emitting light of any color.

The invention now proposes that the light body is flat and the surface serving as the light coupling surface is one of the side surfaces of the light body and that a rear surface opposite the light exit surface and at least one of the side surfaces have a reflective or diffusely backscattering coating. The coating of the at least one side surface is as an optical structure formed integrally (that is to say cohesively) onto the side surface.

For the purposes of the invention, flat is intended to mean that the light body has a surface extension which runs in two mutually perpendicular directions and which is several times greater in each direction than a thickness of the light body. In the context of the invention, a side surface is to be understood as a surface running perpendicular to the surface extension of the light body.

The features mentioned above make it possible, on the one hand, to simulate the flatness and homogeneity of an OLED light source, and on the other hand, such a lighting device can be produced very simply, compactly and inexpensively.

According to a first development of the invention, the optical structure has a plurality of pyramid-like elevations protruding from the side surface. In this way, the optical structure can have excellent reflective properties, so that the light coupled into the light body can be coupled out again from the light body with almost no loss. In particular, total reflection can thus preferably take place in the optical structure. For this purpose, the pyramid-like elevations preferably have a square, pentagonal or hexagonal base area.

A further development of the inventive concept suggests that the optical structure has at least one triangular shape protruding from the side surface, seen in the cross section of the light body, in order to also preferably achieve total reflection in this shape, which increases the optical light yield. In other words, the formation has two oppositely inclined surfaces (towards one another) which meet at an upper vertex. In this way, the light body, which is preferably made of plastic, can be produced and demolded very easily and inexpensively by injection molding.

If the light body has a cross section that exceeds a certain width, it can also be expedient for the optical structure to have several (i.e. at least two) triangular projections protruding from the side surface, seen in the cross section of the light body, each of which is configured as described above are.

According to another development of the invention, light-scattering imperfections are arranged in a distributed manner in the light body. In this way, a certain scattering of the light beams coupled into the light body can be achieved, which leads to an improvement in homogeneous light emission by the lighting device. Because the light-scattering imperfections are distributed throughout the light body and not only on its surface, the light-scattering properties of the light body can also be maintained for a long time in everyday operation of the lighting device in a motor vehicle.

In order to achieve a particularly good homogeneity of the light emission, it has proven to be advantageous if the light body has a degree of transmission (= light permeability) in a range of approximately 85 percent to approximately 95 percent. When light is coupled in, the light body only has a slightly scattering effect. The light body particularly preferably has a transmittance of approximately 90 percent.

According to another embodiment of the concept of the invention, a plurality of illuminants are arranged at such a distance from the side surface of the light body coupling the light that approximately also corresponds to a mutual spacing of the illuminants from one another or between the illuminants. For a homogeneous light emission it has therefore proven to be advantageous, for example, if the distance between the individual illuminants is also about 10 mm with a first-mentioned distance of about 10 mm. This can also contribute to a homogeneous light emission of the lighting device.

In order to bring about the greatest possible light yield and effectiveness of the light module, it is proposed that at least one collecting optics or collimation optics be arranged between the at least one illuminant and the side surface of the light body. For example, when using light-emitting diodes, which are known to have an opening angle of their light emission of up to 180 degrees, light rays emerging in lateral areas can also be “captured”.

Another development of the invention proposes that the light body is fastened on a circuit board which also carries the at least one light source. This development contributes to the ease with which the lighting device can be assembled.

In this case it is very useful if the light body is locked to the circuit board. In this way, the mountability or dismountability of the light body can be optimized.

Under certain circumstances it may be desirable to arrange several such light modules in a lighting device. It is then very useful for easier assembly of the lighting device if several light bodies are made in one piece are connected to each other. The lighting means assigned to the individual light modules can also all be arranged on a common circuit board.

Finally, protection is also desired for a motor vehicle which is equipped with at least one lighting device according to the invention.

Preferred exemplary embodiments of the invention are shown in the figures and are explained in more detail in the following description with reference to the figures. This also makes further advantages of the invention clear. The same reference symbols, even in different figures, relate to the same, comparable or functionally identical components. Corresponding or comparable properties and advantages are achieved, even if a repeated description or reference is not made. The figures are not, or at least not always, to scale. In some figures, proportions or distances can be exaggerated in order to be able to emphasize features of an exemplary embodiment more clearly.

• 1 eine Explosionsdarstellung eines Lichtmoduls der Beleuchtungsvorrichtung,
• 2 eine Schnittdarstellung gemäß Schnittverlauf II aus 1, jedoch nicht in einer Explosionsdarstellung auseinandergezogen,
• 2a die Teilansicht eines Lichtmoduls mit randseitigen Optikstrukturen, in einer ersten Variante,
• 2b eine Darstellung des Lichtmoduls gemäß Ansicht IIb aus 2a,
• 2c die Teilansicht eines Lichtmoduls mit einer randseitigen Optikstruktur, in einer zweiten Variante,
• 2d eine Darstellung des Lichtmoduls gemäß Ansicht IId aus 2c,
• 2e die Teilansicht eines Lichtmoduls mit einer randseitigen Optikstruktur, in einer dritten Variante,
• 2f eine Darstellung des Lichtmoduls gemäß Ansicht Ilf aus 2e,
• 3 eine Prinzipdarstellung des montierten Lichtmoduls,
• 4 eine Explosionsdarstellung einer aus drei Lichtmodulen bestehenden Lichteinheit,
• 5 eine Darstellung einer montierten, als Heckleuchte ausgebildeten Beleuchtungsvorrichtung mit erfindungsgemäßen Lichtmodulen und Lichteinheiten und
• 6 ein Kraftfahrzeug mit erfindungsgemäßen Beleuchtungsvorrichtungen.

It show, each schematically

• 1 an exploded view of a light module of the lighting device,
• 2 a sectional view according to section II 1 , but not pulled apart in an exploded view,
• 2a the partial view of a light module with edge-side optical structures, in a first variant,
• 2 B a representation of the light module according to view IIb 2a ,
• 2c the partial view of a light module with an optical structure on the edge, in a second variant,
• 2d a representation of the light module according to view IId 2c ,
• 2e the partial view of a light module with an optical structure on the edge, in a third variant,
• 2f a representation of the light module according to view Ilf 2e ,
• 3 a schematic diagram of the mounted light module,
• 4th an exploded view of a light unit consisting of three light modules,
• 5 a representation of a mounted, designed as a rear light lighting device with light modules and light units according to the invention and
• 6th a motor vehicle with lighting devices according to the invention.

First of all, the 1 and 2 Referenced. In the figures there is a light module 1 can be seen in the exploded view, which has a flat light body 30th and a circuit board 50 with bulbs 51 includes. The bulbs 51 are preferably designed as light emitting diodes.

The light body 30th can preferably have a rectangular outline and is flat. It has a surface extension F. which is several times greater than its thickness in each direction d .

The light body 30th has marginal side surfaces 31 , 32 , 33 and 34 on. These side surfaces surround a light exit surface 35 . The light emitting surface 35 lies on a rear surface 36 opposite to.

The light body 30th is designed as a light guide and preferably has a degree of transmission (a light permeability) in a range from about 85 percent to about 95 percent. The degree of transmission is particularly preferably approximately 90 percent.

The only slight scattering property of the light body 30th is caused by light-scattering imperfections 38 caused that distributed in the light body 30th are arranged. The light-scattering imperfections 38 can enter the light body as interfering particles during manufacture 30th have been introduced. Alternatively, it is also conceivable to use the light-scattering imperfections 38 via laser processing into the light body 30th bring in.

The already mentioned board 50 with the lighting means designed as light emitting diodes (LEDs) 51 is at a close distance b below the lower side surface that can be seen in the figures 34 arranged. The lower side face 34 thus serves as a light coupling surface. The distance b is preferably about 10 millimeters. It can also be seen that the light sources 51 a mutual distance a have, which in the exemplary embodiment is also preferably about 10 millimeters.

The light body 30th is preferably colored red. It can consist of PMMA (polymethyl methacrylate) or PC (polycarbonate), for example.

There are also coatings 11 and 12th indicated by dashed lines. The coating 11 covers the back surface 36 . The coatings 12th cover the side surfaces 31 , 32 and 33 . The coatings 11 , 12th are both reflective or diffuse backscattering. The coating 11 can be provided with a corresponding layer for this purpose, preferably by means of (preferably white) printing or by means of (optionally masked, metallic) vapor deposition. Like the cover 12th can be designed in detail, will be explained later. In contrast to the exemplary embodiment, it is conceivable that not all of the edge-side side surfaces 31 , 32 and 33 from the coating 12th are coated. For example, it is conceivable that only the lower side surface 34 opposite side face 31 a cover 12th having.

The formation of the light body 30th causes over the bulbs 51 into the light body 30th coupled light rays L. at the light-scattering imperfections 38 “Get stuck” or be diffusely scattered. This contributes to a homogeneous illumination of the light body 30th at.

Rays of light L. which on the coatings 11 and or 12th impinge, are there preferably using a total reflection in the direction of the light body 30th reflected back or diffusely backscattered. This makes a significant contribution to achieving homogeneous light emission and a high light yield of the light module 1 done. However, due to the aforementioned imperfections 38 this effect is still optimized.

Based on 2a until 2f will now be described how the coatings 12th can be formed. The coatings 12th at least are as optical structures 10a , 10b and or 10c trained (see also 1 and 2 ).

Such is a flat body of light 30a with coatings 12th shown, each as an optical structure 10a are trained. Any optical structure 10a consists of the respective side face 31 , 32 or 33 protruding, pyramid-like elevations 6th with a polygonal base. The base can preferably be triangular, square, pentagonal or hexagonal. Other trainings are conceivable. Through the pyramid-like elevations 6th shows the coating 12th a kind of reflector optics. A production can for example take place by electroplating, so that the edges and the tips of the pyramid-like elevations 6th are neatly formed (cf. 2a and 2 B) .

In the 2c and 2d is the coating 12th a flat body of light 30b as an optical structure 10b educated. The optical structure 10b is as one in the cross section of the light body 30b seen triangular formation 7th educated. The molding 7th extends along the respective side surface (here 31, alternatively or additionally, other of the side surfaces are conceivable) and has two oppositely inclined surfaces (towards one another) 7a on. Seen in cross-section, the formation 7th the appearance of a gable roof. A coupled light beam is purely exemplary L. drawn, which by the molding 7th into the light body 30b is reflected back and then through the coating 11 the back surface 36 in the direction of the light exit surface 35 is reflected.

From the 2e and 2f it can be seen that with a flat light body 30c also a cover 12th can be used by an optical structure 10c with several (i.e. at least two in cross-section triangular shaped projections 7th is formed. Such a solution can be advantageous if the flat light body 30c exceeds a certain thickness.

Based on 3 you can now see how the light module 1 can be preferably mounted. So can on the board 50 angular brackets 53 be present, which with the board 50 connected, preferably screwed or glued.

The flat body of light 30th can on its opposite, vertical side surfaces 32 , 33 in each case protruding locking means in the lower area 18th exhibit. The locking means 18th engage in counter-locking means 52 of the resiliently deflectable brackets 53 on.

Alternatively, it is also conceivable that the light body 30th at least one flange-like projection 39 with a bend 39a and with at least one molded locking body 39b having. The locking body 39b can then in a locking opening 50a the board 50 intervene with a latching action. In this way, a simple, quickly assembled connection can be created.

Furthermore, are between the lower side surface 34 of the light body 30th and the light sources 51 each collecting optics 60 indicated by dashed lines. These are optional and contribute to that of the light sources 51 emitted light rays L. "Collected" and in the direction of the light body 30th be aligned. The collecting optics 60 can also be attached to the lower side surface 34 be molded.

the 4th is a light unit 100 to see which of three light bodies 30th (as described), each of which has a coating on an upper side surface 12th exhibit.

The light bodies 30th can be connected to one another in one piece, for example by a web-like connecting element 37 . You can thus on can be easily produced in one operation, preferably in an injection molding tool.

Finally, there is a circuit board 50 ' present, which is made correspondingly longer than the board 50 (see. 1 ) and, for example, nine lamps 51 takes up, of which three each are a light body 30th assigned.

Based on 5 is shown that the light modules 1 or light units consisting of these 100 ' respectively 100 " also in a lighting device 2 of a motor vehicle indicated by dashed lines K can be used. The lighting device 2 can be a rear lighting of the motor vehicle K be, with a body-side part 2a the lighting device 2 in a body 3 and a tailgate-side part 2 B the lighting device 2 in a tailgate 4th of the motor vehicle K can be installed.

It is conceivable to use a control unit, not shown here, to control the individual light modules 1 to be controlled one after the other in such a way that technical lighting animations A1 respectively A2 (compare arrow direction). This is conceivable, for example, to implement a so-called coming home or leaving home function.

Finally shows the 6th the entire motor vehicle K , in which two lighting devices serving as rear lights 2 are installed. A control unit 5 is used via signal and control lines S. for controlling the lighting devices 2 .

In the 2c-2f and 4 is a coating 12th only on the upper side surface 31 shown. A coating can deviate from this 12th alternatively or additionally, however, also on the side surfaces 32 and 33 to be available.

List of reference symbols

1

Light module

2

Lighting device

2a

Body-side part of the lighting device

2 B

Tailgate-side part of the lighting device

3

body

4th

Tailgate

5

Control unit

6th

pyramid-like elevations

7th

triangular projections

7a

inclined surfaces

10a, 10b, 10c

Optical structure

11

coating

12th

coating

18th

Locking means

30, 30a, 30b, 30c

flat light body

31

Side face

32

Side face

33

Side face

34

Side face

35

Light exit surface

36

back surface

37

bar-like connecting element

38

light-scattering imperfections

39

flange-like molding

39a

Angulation

39b

Locking body

50, 50 '

circuit board

50a

Locking opening

51

Illuminants, LEDs

52

Counter-locking means

53

bracket

60

Collecting optics

100, 100 ', 100 "

Light units

a

distance

A1, A2

Animations

b

distance

d

thickness

F.

Area extension

K

Motor vehicle

L.

Rays of light

S.

Signal and control line

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011110630 A1 [0002]
• DE 102011110629 A1 [0003]
• DE 19860697 A1 [0004]
• DE 19902774 A1 [0005]

Claims (12)

Lighting device (2; 2a, 2b) for a motor vehicle (K), with at least one light module (1), which has a light body (30) and at least one illuminant (51), the light rays (L) of which in a surface serving as a light coupling surface ( 34) of the light body (30) can be or are coupled in, the light beams (L) outwardly in the direction of a light emission direction of the lighting device (2; 2a) via a light exit surface (35) surrounded by side surfaces (31-34) of the light body (30) , 2b) can emerge or emerge, characterized in that the light body (30) is flat and the surface serving as the light coupling surface is one of the side surfaces (31-34) of the light body (30) and one of the light exit surface (35) opposite, rear Surface (36) and at least one of the side surfaces (31-33) have a reflective or diffuse backscattering coating (11, 12), the coating (12) of the at least one S side surface (31-33) is designed as an optical structure (10a, 10b, 10c) formed in one piece on the side surface (31-33). Lighting device (2; 2a, 2b) according to Claim 1 , characterized in that the optical structure (10a) has a plurality of pyramid-like elevations (6) protruding from the side surface (31). Lighting device (2; 2a, 2b) according to Claim 1 , characterized in that the optical structure (10b) has at least one triangular projection (7) protruding from the side surface (31) and seen in the cross section of the light body (30). Lighting device (2; 2a, 2b) according to Claim 1 , characterized in that the optical structure (10b) has a plurality of triangular formations protruding from the side surface (31), seen in the cross section of the light body (30). Lighting device (2; 2a, 2b) according to one of the preceding claims, characterized in that light-scattering imperfections (38) are arranged in a distributed manner in the light body (30). Lighting device (2; 2a, 2b) according to Claim 5 , characterized in that the light body (30) has a transmittance in a range from about 85% to about 95%, preferably a transmittance of about 90%. Lighting device (2; 2a, 2b) according to one of the preceding claims, characterized in that a plurality of illuminants (51) are arranged at a distance (b) from the side surface (34) coupling in the light beams (L), the distance (b) corresponds to a mutual distance (a) of the illuminants (51) from one another. Lighting device (2; 2a, 2b) according to one of the preceding claims, characterized in that at least one collecting optic (60) is arranged between the at least one lighting means (51) and the side surface (34). Lighting device (2; 2a, 2b) according to one of the preceding claims, characterized in that the light body (30) is attached to a circuit board (50) which also carries the at least one illuminant (51). Lighting device (2; 2a, 2b) according to Claim 9 , characterized in that the light body (30) is locked to the circuit board (50). Lighting device (2; 2a, 2b) according to one of the preceding claims, characterized in that several light bodies (30) are integrally connected to one another. Motor vehicle (K), characterized by at least one lighting device (2; 2a, 2b) according to one of the preceding claims.

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