DE102019128342A1 - Lighting device for a motor vehicle - Google Patents

Abstract

The present invention relates to a lighting device (100) for a motor vehicle (300) at least comprising: a light guide element (1), the light guide element (1) having a light coupling surface (10) at a first end section (11) and / or at a second end section (12) and a light decoupling section (13) which extends at least partially between the first end section (11) and the second end section (12) and has a front side (13a) and a rear side (13b), the front side (13a) of the Light outcoupling section (13) is oriented in the direction of a cover plate (3) of the lighting device (100), and - a lighting means (2), wherein the lighting means (2) for coupling light into the light guide element (1) is arranged on the light coupling surface (10), wherein a shading device (4) is arranged between the front side (13a) of the light outcoupling section (13) and the cover plate (3), wherein the shading device ngsvorrichtung (4) between at least one locally transparent switching state (40A), in which the shading device (4) is at least segmentally transparent to light emerging from the light decoupling section (13), and an opaque switching state (40B), in which the shading device (4) is opaque for light emerging from the light decoupling section (13), is switchable.

Description

The present invention relates to a lighting device for a motor vehicle at least comprising a light guide element, the light guide element having a light coupling surface at a first end section and / or at a second end section and a light output section extending at least partially between the first end section and the second end section with a front side and with a rear side, wherein the front side of the light coupling-out section is oriented in the direction of a light exit opening of the lighting device, and a lighting means, the lighting means for coupling light into the light guide element being arranged on the light coupling-in surface.

STATE OF THE ART

In the course of the steadily advancing traffic networking and autonomization, communication between road users and between road users and the traffic infrastructure or traffic networks plays an important role. A contribution to this so-called “vehicle-to-everything” networking can be made by a lighting device of a vehicle as a signal light for optical communication with other road users. So that the greatest possible variety of distinguishable signals is available for communication, it is necessary that the lighting device used is set up to generate a corresponding variety of different light impressions and / or light sequences.

For example, the FR3043167 A1 a lighting device for a motor vehicle with a light source arranged on an end-face light coupling surface of an elongated light guide, a light output surface being formed by a lateral surface of the light guide, the light guide having switchable optical barrier means, for example electrochromic inserts, by means of which the light flux along the light guide is selectively can be blocked. The scope of light impressions that can be generated with this lighting device is relatively limited and is essentially geared towards a function as a direction indicator with an animated, flowing flashing light.

The US 2018/0334088 A1 discloses a vehicle lighting device with an illuminated radiator grille, wherein at least one light source is arranged on a plurality of grill ribs, and wherein combinations of light effects of the illuminated grill ribs for displaying the operating behavior of the vehicle can be generated by means of a control unit. The light sources are designed in particular as light-emitting diodes on printed circuit boards and integrated frontally in the grill ribs, so that the light-emitting diodes are emitted in the direction of travel.

DISCLOSURE OF THE INVENTION

It is the object of the present invention to propose a further development of a lighting device for a motor vehicle, which can be used in particular as a signal light for optical communication with a large number of light impressions and / or light sequences that can be generated.

This object is achieved on the basis of a lighting device according to the preamble of claim 1 in conjunction with the characterizing features. Advantageous further developments of the invention are given in the dependent claims.

• - ein Lichtleitelement, wobei das Lichtleitelement eine Lichteinkopplungsfläche an einem ersten Endabschnitt und/oder an einem zweiten Endabschnitt aufweist und einen sich zwischen dem ersten Endabschnitt und dem zweiten Endabschnitt wenigstens teilweise erstreckenden Lichtauskopplungsabschnitt mit einer Vorderseite und mit einer Rückseite umfasst, wobei die Vorderseite des Lichtauskopplungsabschnitts in Richtung einer Abschlussscheibe der Beleuchtungseinrichtung orientiert ist, und
• - ein Leuchtmittel, wobei das Leuchtmittel zur Lichteinkopplung in das Lichtleitelement an der Lichteinkopplungsfläche angeordnet ist.

The invention relates to a lighting device at least comprising:

• - A light guide element, wherein the light guide element has a light coupling surface at a first end section and / or at a second end section and comprises a light output section extending at least partially between the first end section and the second end section with a front side and with a rear side, the front side of the light output section is oriented in the direction of a cover plate of the lighting device, and
• - A lighting means, wherein the lighting means for coupling light into the light guide element is arranged on the light coupling surface.

The invention includes the technical teaching that a shading device is arranged between the front side of the light outcoupling section and the cover lens, the shading device between at least one locally translucent switching state in which the shading device is at least segmentally permeable for light emerging from the light outcoupling section, and an opaque one Switching state in which the shading device is impermeable to light emerging from the light decoupling section can be switched.

The invention is based on the idea of creating, with the shading device, a device specially designed for forming optical signals and signal sequences, the at least one light source with the associated light guide element functioning as backlighting. This backlighting can in particular take the form of a line or area emitter with homogeneous illuminance and the desired light impression is only generated when it passes through the shading device, depending on its switching state. The completely translucent switching state, in which all light emerging from the light decoupling section of the light guide element can pass the shading device, and the completely opaque switching state, in which all light is absorbed by the shading device, represent the two extreme cases of the possible switching states A large number of light-permeable switching states are provided in which the shading device has different translucency in sections or segments, for example horizontally alternating areas with complete transparency or complete opacity. The shading device is thus designed in such a way that its light permeability varies locally and can be switched in a targeted manner. Given a sufficiently small subdivision of the shading device into individually switchable sections or segments, complex light images for communication, for example luminous letters or lettering, can thus also be displayed. Compared to the one in the US 2018/0334088 A1 disclosed prior art, in which the variety and complexity of the light impressions that can be represented depend on the number of lighting means integrated in the lighting device, a basically very broad signal spectrum can be generated with the lighting device according to the invention using only one lighting means, whereby the specific configuration the shading device plays the decisive role in this context.

In an advantageous embodiment of the lighting device according to the invention, the shading device is designed as a liquid crystal display. The function of a liquid crystal display (liquid crystal display, short: LCD) is based on the fact that liquid crystals influence the polarization direction of transmitted light when a certain amount of electrical voltage is applied. The necessary light polarization is generated by means of polarization filters. The shading device according to the invention, designed as a liquid crystal display, has a large number of segments, for example a uniform pixel grid, with an electrical voltage being able to be applied to each segment, for example by means of applied thin-film transistors, so that the segments can change their transparency independently of one another.

Alternatively, the shading device comprises a plurality of mechanical flaps, the mechanical flaps being switchable independently of one another. This embodiment represents an alternative to the use of a liquid crystal display that is reduced in terms of its signal range but is cost-effective.

In a further embodiment of the lighting device according to the invention, the light guide element is designed as a fiber-shaped or ribbon-shaped light guide. The light guide is based on reflection at the interface of the light guide and thread-like or ribbon-shaped light guides can be made from flexible materials so that they can, for example, simulate the contour of the vehicle body or a vehicle front end. The light is typically coupled in via a front or edge coupling surface.

A plurality of decoupling elements for decoupling light from the front side of the light decoupling section is advantageously arranged along the rear side of the light decoupling section of the light guide element. In particular, microprisms protruding into the light guide or other light-refracting surface structures, for example dimple patterns, can be used as decoupling elements. When using a high density of outcoupling elements along the entire rear side of the light outcoupling section, a homogeneous, two-dimensional light impression is created, which represents suitable backlighting for the shading device.

Alternatively, the light guide element can be designed as a light scattering fiber, with scattering elements for light extraction being received in the body of the light extraction section. Typically 50-500 nm large nanoparticles are used as scattering elements, which are finely dispersed along the entire light outcoupling section and lead to an essentially isotropic light outcoupling.

The lighting device with light scattering fiber therefore preferably comprises a reflector, the reflector being designed to reflect light emerging from the rear side of the light decoupling section in the direction of the cover lens. This ensures a high light efficiency of the lighting device according to the invention.

In particular, the reflector can be designed as a reflective coating on the rear side of the light coupling-out section. This embodiment requires the least amount of space and does not require any additional assembly effort.

The lighting device preferably has two lighting means, a first lighting means being arranged on the light coupling surface on the first end section of the light guide element and a second lighting means being arranged on the light coupling surface on the second end section. In this way, in particular with long light guide elements, sufficient light intensity and homogeneity of the backlighting can be guaranteed.

With a further advantage, the lighting means is designed as a semiconductor light source. This can in particular be designed as a light-emitting diode or as a multi-colored light-emitting diode unit or as a laser diode or as a multi-colored laser diode unit. Light or laser diodes are efficient and inexpensive light sources, which also only take up a small amount of space. By using a light or laser diode unit which comprises a plurality of diodes with different light colors, the variety of light impressions that can be generated with the lighting device is significantly increased.

In particular, the lighting device according to the invention is used as a signal light for communication with other road users and / or with a traffic infrastructure and / or with a traffic network, the lighting device being used to emit a large number of different optical signals and / or optical signal sequences. Such a use serves to increase traffic safety and efficiency. A pronounced traffic network by means of communication between all participants also represents, in particular, a central basis for autonomous driving. The use of optical signals is particularly suitable as a communication channel with human road users. For example, a pedestrian at a pedestrian crossing could be signaled by outputting a signal sequence made up of animated, green light impressions that an approaching autonomous vehicle has recognized the pedestrian and is allowing passage across the lane.

The invention further relates to a front end for a motor vehicle with a lighting device in one of the aforementioned embodiments, the lighting device being arranged on the front end. In particular, the front end has two headlights and the lighting device is arranged in the area between the headlights.

PREFERRED EMBODIMENT OF THE INVENTION

• 1 eine Vorderansicht einer erfindungsgemäßen Beleuchtungseinrichtung,
• 2 eine vertikale Querschnittsansicht einer erfindungsgemäßen Beleuchtungseinrichtung,
• 3a,b vertikale Querschnittsansichten einer erfindungsgemäßen Beleuchtungseinrichtung,
• 4 eine horizontale Querschnittsansicht einer erfindungsgemäßen Beleuchtungseinrichtung,
• 5 eine Darstellung eines Schaltzustandes einer erfindungsgemäßen Abschattungsvorrichtung, und
• 6 eine perspektivische Ansicht eines erfindungsgemäßen Frontends eines Kraftfahrzeugs.

Further measures improving the invention are shown in more detail below together with the description of a preferred exemplary embodiment of the invention with reference to the figures. It shows:

• 1 a front view of a lighting device according to the invention,
• 2 a vertical cross-sectional view of a lighting device according to the invention,
• 3a, b vertical cross-sectional views of a lighting device according to the invention,
• 4th a horizontal cross-sectional view of a lighting device according to the invention,
• 5 a representation of a switching state of a shading device according to the invention, and
• 6th a perspective view of a front end according to the invention of a motor vehicle.

1 shows a front view of a lighting device according to the invention 100 with two lamps 2 in arrangement at the first and second end portions 11 , 12th of the light guide element 1 , which is behind the shading device 4th is located. The light guide element 1 has the shape of a fiber-shaped light guide with a round cross-section. The light is coupled in via the two frontal light coupling surfaces 10 and the coupling-out via the lateral surface of the cylindrical light coupling-out section 13th , especially on its front 13a which in the direction of the shading device 4th is oriented so that the emerging light acts as backlighting. The use of two light sources 2 generates a high light intensity in the light guide and contributes to the homogenization of the light impression. In a simpler embodiment, only one light source can serve as a light source and the opposite end face can be mirrored, for example. The bulbs 2 can for example be formed by light or laser diodes and / or multicolored light or laser diode units.

2 and 3a, b show lighting devices according to the invention 100 in a vertical cross-sectional view, ie the viewing direction runs along the direction of propagation of the into the light guide element 1 coupled light. The lighting device 100 each includes a housing 6th with a transparent cover lens that closes the housing opening 3 . Inside the case 6th is the light guide element 1 in the form of a light guide with a cylindrical light decoupling section 13th arranged, its front side 13a towards the lens 3 is oriented.

Along the back 13b are decoupling elements 14th arranged in the form of microprisms, which the light so in the direction of the front 13a break that the critical angle of total reflection is exceeded and consequently light is coupled out. The refraction of light can with suitable dimensioning of the decoupling elements 14th to a strongly directed light decoupling from the light guide element 1 lead so that with the lighting device according to the invention 100 For example, a smaller radiation angle can be realized than with the prior art from FIG US 2018/0334088 A1 used light-emitting diodes without additional optics.

Between light guide element 1 and cover lens 3 is the shading device 4th arranged in the in 2 illustrated embodiment as a liquid crystal display 41 , and in the 3a, b as mechanical flaps 42 is trained.

The liquid indicator 41 The essential components include the front and rear polarization filters, the optically active medium and field effect transistors for control. Since liquid crystal displays represent well-known devices from the prior art and, in principle, a large number of different embodiments are suitable for use in the lighting device according to the invention 100 is, we are conscious of a more detailed representation of the liquid crystal display 41 waived.

The shading device 4th in the form of individually controllable flaps 42 or flap pairs is in the 3a in the opaque switching state 40B with closed flaps 42 and in the 3b in a translucent switching state 40A with flaps open 42 shown. Along the light guide element 1 , ie along the direction of view shown, there is preferably a large number of individually controllable pairs of flaps 42 arranged so that a variety of translucent switching states 40A exists, in each of which there is at least one flap 42 is open.

4th shows a horizontal cross-sectional view of a lighting device according to the invention 100 with a light guide element designed as a light scattering fiber 1 and a shading device 4th in the form of a liquid crystal display 41 .

The the light guide element 1 The light scattering fiber representing the light is formed by a conventional light guide, which also has a large number of finely dispersed scattering elements 15th in the body of the light extraction section 13th having. The scattering elements 15th consist of nanoparticles, the diameter of which is dimensioned in such a way that they act as scattering centers for light with wavelengths from the visible range. The scattering elements 15th are in 4th For the sake of clarity, they are oversized and shown in low density; in an actual component they are nanoscale in size and in a dense, finely dispersed arrangement. The light scattering on the scattering elements 15th takes place essentially statistically undirected and in the direction of the lateral surface of the light decoupling section 13th scattered light emerges from the light guide element 1 if the angle of incidence exceeds the critical angle of total reflection. Such light scattering fiber is known for example under the trade name Corning ^® Fibrance ^® Light-Diffusing Fiber.

Around the back 13b of the light extraction section 13th , ie for example along a segment of a circle of 180 °, is a reflector 5 arranged in the form of a reflective layer, for example a vapor-deposited metal layer. As a result, light scattered in this direction is prevented from leaving the light guide element and is reflected back into the light coupling-out section, so that the light is therefore only coupled out via the front side 13a takes place. To avoid light losses at the end face of the second end section 12th which one is used to couple light from the lamp 2 used light coupling surface 10 at the first end section 11 opposite, the reflective layer extends 5 beneficial to this too.

In front of the light guide element 1 is the liquid crystal display 41 arranged, which via the control unit connected to it 43 can be switched between the various switching states. That of the light guide element 1 emitted light is when hitting the shading device 4th Depending on their switching state, either locally absorbed on an opaque segment or a segment switched to be transparent can pass and through the cover lens 3 the lighting device 100 leave.

5 shows a representation of an exemplary switching state 40A a shading device according to the invention 4th in the form of a liquid crystal display 41 . In the shown, locally translucent switching state 40A the liquid crystal display has both translucent segments 40a as well as opaque segments 40b on. With homogeneous backlighting through the one behind the shading device 4th arranged light guide element corresponds to the spatial structure of the lighting device according to the invention 100 generated light impression the image of the switching status 40A . The translucent or opaque segments 40a , 40b in 5 can each be constructed from a plurality of smaller segments which are in the same switching state. The variety of switchable switching states and corresponding light signals depends in particular on the density of the individually switchable segments of the liquid crystal display 41 from. This can be adapted to the specific purpose and the required scope of communication signals that can be generated by the lighting device 100 be adjusted.

6th shows a perspective view of a front end according to the invention 200 of a motor vehicle 300 . The front end 200 includes the two headlights 70 and the grille 80 , wherein a lighting device according to the invention 100 between the headlights 70 is arranged. Light guide element 1 and shading device 4th have the elongated shape of a rib of the radiator grille 80 on and are at the curved contour of the front end 200 customized. In this exposed arrangement at the front end 200 of the vehicle 300 is the lighting device 100 Visible to other road users from afar and from a wide range of viewing angles.

The embodiment of the invention is not restricted to the preferred exemplary embodiment specified above. Rather, a number of variants are conceivable which make use of the solution shown even in the case of fundamentally different designs. All of the features and / or advantages arising from the claims, the description or the drawings, including structural details and spatial arrangements, can be essential to the invention both individually and in a wide variety of combinations.

List of reference symbols

100

Lighting device

200

Front end

300

Motor vehicle

1

Light guide element

10

Light coupling surface

11

first end section

12th

second end section

13th

Light extraction section

13a

front

13b

back

14th

Decoupling element

15th

Scattering element

2

Bulbs

3

Cover lens

4th

Shading device

40A

translucent switching state

40B

opaque switching state

40a

translucent segment

40b

opaque segment

41

Liquid crystal display

42

flap

43

Control unit

5

reflector

6th

casing

70

Front headlights

80

Grille

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

• FR 3043167 A1 [0003]
• US 2018/0334088 A1 [0004, 0009, 0024]

Claims (15)

Lighting device (100) for a motor vehicle (300) at least comprising: - a light guide element (1), wherein the light guide element (1) has a light coupling surface (10) on a first end section (11) and / or on a second end section (12) and a light decoupling section (13) which extends at least partially between the first end section (11) and the second end section (12) and has a front side (13a) and a rear side (13b), the front side (13a) of the light decoupling section (13) in Direction of a cover plate (3) of the lighting device (100) is oriented, and - a lighting means (2), wherein the lighting means (2) for coupling light into the light guide element (1) is arranged on the light coupling surface (10), characterized in that between a shading device (4) is arranged on the front side (13a) of the light outcoupling section (13) and the cover plate (3), the shading device (4) between at least one locally transparent switching state (40A), in which the shading device (4) is transparent at least in segments for light emerging from the light decoupling section (13), and an opaque switching state (40B) in which the shading device (4) for light emerging from the light decoupling section (13) is impermeable, can be switched. Lighting device (100) Claim 1 , characterized in that the shading device (4) is designed as a liquid crystal display (41). Lighting device (100) Claim 1 characterized in that the shading device (4) comprises a plurality of mechanical flaps (42), the mechanical flaps (42) being switchable independently of one another. Lighting device (100) according to one of the preceding claims, characterized in that the light guide element (1) is designed as a fiber-shaped or ribbon-shaped light guide. Lighting device (100) according to one of the preceding claims, characterized in that a plurality of coupling-out elements (14) for coupling light out of the front (13a) of the light coupling-out section (13) are arranged along the rear side (13b) of the light coupling-out section (13). Lighting device (100) according to one of the preceding claims, characterized in that the light guide element (1) is designed as a light scattering fiber, with scattering elements (15) for light extraction being received in the body of the light extraction section (13). Lighting device (100) Claim 6 , characterized in that the lighting device (100) comprises a reflector (5), the reflector (5) being designed to reflect light emerging from the rear side (13b) of the light decoupling section (13) in the direction of the cover lens (3). Lighting device (100) Claim 7 , characterized in that the reflector (5) is designed as a reflective coating on the rear side (13b) of the light decoupling section (13). Lighting device (100) according to one of the preceding claims, characterized in that the lighting device (100) has two lighting means (2), a first lighting means (2) on the light coupling surface (10) on the first end section (11) of the light guide element (1) ) and a second illuminant (2) is arranged on the light coupling surface (10) on the second end section (12). Lighting device (100) according to one of the preceding claims, characterized in that the lighting means (2) is designed as a semiconductor light source. Lighting device (100) Claim 10 , characterized in that the lighting means (2) is designed as a light-emitting diode or as a multi-colored light-emitting diode unit or as a laser diode or as a multi-colored laser diode unit. Lighting device (100) according to one of the preceding claims, characterized in that the lighting device (100) is used as a signal light for communication with other road users and / or with a traffic infrastructure and / or with a traffic network. Lighting device (100) Claim 12 , characterized in that the lighting device (100) is used to emit a large number of different optical signals and / or optical signal sequences. Front end (200) for a motor vehicle (300) with a lighting device (100) according to one of the preceding claims, characterized in that the lighting device (100) is arranged on the front end (200). Frontend (200) according to Claim 14 , wherein the front end (200) has two front headlights (70), characterized in that the lighting device (100) is arranged in the area between the front headlights (70).

Images