Lighting device for vehicle

Abstract

The invention relates to a lighting device for a vehicle (1), comprising a light-emitting surface unit (7, 7 ') which can be fastened to a body component (6) and / or a trim component of the vehicle (1) and comprising a light source (8) for illuminating the light-emitting surface unit (7, 7'), the light-emitting surface unit (7, 7 ') comprising an electrophoretic display (9) having a plurality of microcapsules (18) which can be excited in color.

Description

Technical Field

[0001] The invention relates to a lighting device for a vehicle, the lighting device comprising a light-emitting surface unit which can be fixed on a body component and / or a decorative component of the vehicle and a light source for illuminating the light-emitting surface unit. Background Art

[0002] DE 10 2019 118 527 A1 discloses a lighting device for a vehicle, which is fixed to a body part on the outside of the vehicle or to a decorative part on the inside of the vehicle for contour lighting. The lighting device comprises an elongated optical waveguide and a light source, which couples light into the optical waveguide at one end face of the optical waveguide. The optical waveguide has a coupling-out device so that the coupled-in light is coupled out on a linear portion of the circumference, which simultaneously forms the front face of the lighting device. The optical waveguide thus forms a light-emitting surface unit of the lighting device. If light of different light colors is to be emitted from the optical waveguide or the light-emitting surface unit, the optical waveguide must have a color-changing element for converting the coupled-in light when the light source is configured as a laser light source. A disadvantage of the known lighting device is that a specific color tone, such as the color of the vehicle, can only be adjusted with relatively great effort.

[0003] WO 2010 / 003654 A1 and EP 3 234 042 B1 disclose an electrophoretic display having a plurality of color-excitable microcapsules, which are used, for example, as electronic paper for displaying texts, such as in the Kindle product from Amazon.

[0004] In the automotive industry, it is desirable to visually highlight the contours of a vehicle, for example in the logo color of the vehicle manufacturer. In addition to design reasons, contour lighting can also be used to make the vehicle more recognizable to other road users. Summary of the invention

[0005] The object of the present invention is therefore to improve a lighting device for a vehicle in such a way that contour lighting with a specific, predefined light color can be provided in a simple manner in terms of production technology.

[0006] In order to achieve this object, the invention is characterized in that, in conjunction with the preamble of claim 1 , the luminous area unit comprises an electrophoretic display having a plurality of color-excitable microcapsules.

[0007] The particular advantage of the lighting device according to the invention is that the light color of the luminous surface unit desired by the vehicle manufacturer can be induced in a simple manner by means of color-excitable microcapsules. When manufacturing the lighting device, the microcapsules are loaded with an electric field and / or a magnetic field so that color particles of a specific light color accumulate on a predetermined side of the microcapsules and are fixed there after the field is stopped. Thus, when manufacturing the lighting device, the desired color is "burned" into the luminous surface unit. No change in the output light color is provided during vehicle operation. As a result, the luminous surface unit can advantageously have a specific light color, for example, a light color that is consistent with a component adjacent to the lighting device.

[0008] According to a preferred embodiment of the present invention, the color particles have at least three or four different color particles or different color particle types, so that these different color particles can be positioned on the same side of the microcapsule in a predetermined mixing ratio according to the excitation. If a plurality of four different color particles or color particle types are involved, for example, cyan, magenta, yellow and white, more than 4000 different colors can be mixed, so that matching luminous colors of the luminous surface unit can be provided to vehicle manufacturers.

[0009] According to one embodiment of the invention, a plurality of image points are formed by a plurality of microcapsules, the size of which is in the millimeter range and which are therefore only slightly resolvable by the human eye. The image points form a minimum set of adjacent microcapsules which can also be excited to a predetermined color by a minimum portion of the external field. This determines the color resolution of the electrophoretic display. This advantageously makes it possible to achieve a uniform color impression of the lighting device.

[0010] According to one embodiment of the invention, the light source is switched on or off as a function of an ambient brightness sensor, so that illumination by the luminous area unit is ensured in darkness or at very low brightness (dimness).

[0011] According to one embodiment of the invention, a light guide is arranged in front of the electrophoretic display in the main radiation direction, into which light guide the light can be coupled, thereby ensuring a uniform illumination viewed over the surface of the lighting device.

[0012] Further advantages of the invention result from the further dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The accompanying drawings are as follows:

[0014] Figure 1 A front view of a vehicle is shown with the lighting device according to the invention as a contour lighting device of the vehicle;

[0015] Figure 2 Shown along Figure 1The section line II-II in FIG. 1 passes through a cross section of the contour lighting device; and

[0016] Figure 3 An alternative embodiment is shown along Figure 1 The section line II-II in FIG. 1 passes through a cross section of the contour lighting device. DETAILED DESCRIPTION

[0017] The vehicle 1 has a lighting device 2 designed as a headlight for generating a predetermined light distribution, for example a low-beam light distribution or a high-beam light distribution.

[0018] In addition, the vehicle 1 has a lighting device 3 for contour lighting, which is configured in an elongated or linear manner. The lighting device 3 includes a front edge region of the vehicle 1, in which the headlights 2 and the radiator grille 4 are located. In the present embodiment, the lighting device 3 extends in a closed or elliptical manner.

[0019] As from Figure 2 and 3 As can be seen in FIG, the lighting device 3 extends in a recess 5 of a body component 6 of the vehicle 1. The recess 5 is designed in a groove-shaped or linear manner.

[0020] The lighting device 3 for contour lighting according to the present invention mainly comprises a light-emitting surface unit 7 and a light source 8. The light-emitting surface unit 7 emits light in a main irradiation direction H from the recess 5 of the vehicle body component 6.

[0021] According to Figure 2 In the first embodiment of the present invention, the luminous area unit 7 has, on the one hand, an electrophoretic display 9 which bears against a bottom 10 of the recess 5, and, on the other hand, has an optical waveguide 11 which is arranged in front of the display 9 in the main irradiation direction H. In the present embodiment, the optical waveguide 11 is arranged spaced apart from the display 9. According to an alternative embodiment of the present invention which is not shown, the optical waveguide 11 can also be arranged directly on the front side 12 of the display 9.

[0022] The light guide 11 has such dimensions that it covers the electrophoretic display 9 . The front side 13 of the light guide 11 preferably terminates flush with a vehicle outer skin 14 formed by the body component 6 .

[0023] The electrophoretic display 9 comprises a base 15 and a transparent protective cover 16, which simultaneously forms the front face 12 of the display 9. In the base 15, a plurality of image points 17 or pixels 17 are arranged on a substrate, which have dimensions in the millimeter range. Each image point 17 comprises a plurality of microcapsules 18, which have dimensions in the micrometer range, for example, in the range between 10 μm and 80 μm. The image point 17 forms the smallest unit of adjacent microcapsules 18 of the same color, which can be excited by an external field, and has no own boundaries, such as a skin.

[0024] The microcapsules 18 each have color particles 19, 20, which can change their position by means of an externally applied electric field or magnetic field or electromagnetic field. If the microcapsules 18 have, for example, white color particles 19 and black color particles 20 (second color particles of a second color), then by applying an electric field, for example, applying an anode 21 on a first side 22 of the microcapsules 18 and applying a cathode 23 on a second side 24 of the microcapsules 18, the white color particles 19 can be accumulated or deposited on the first side 22 of the microcapsules 18 and the black color particles 20 can be accumulated or deposited on the opposite second side 24 of the microcapsules. If the first side 22 of the microcapsules 18 is arranged oriented on the side facing the light conductor 11 or in the direction of the main irradiation direction H, the microcapsules form a color impression on the front side 12 of the display 9, so that the electrophoretic display 9 appears white in terms of light color when excited in the same manner over the length of the base 15. Since the desired white color of the luminous surface unit 7 can maintain visual prominence as the radiator grille 4 even in low light or in the dark compared to the body component 6 which remains gray, the light source 8 is arranged on a narrow side 25 of the optical waveguide 11. The light source 8 is designed, for example, as an LED light source and is arranged on a printed circuit board 26 which is fixed to a side wall 27 of the recess 5. The light emitted by the light source 8 is coupled into the optical waveguide 11 on the narrow side 25.

[0025] The optical waveguide 11 is designed in such a way that, on the one hand, the first light component 28 coupled in is coupled out at the front side 13 of the optical waveguide 11 , see Figure 2 On the other hand, the optical waveguide 11 is designed so that the second light component 29 is coupled out on the rear side 30 of the optical waveguide 11 in the direction of the display 9 and is reflected to illuminate the display 9, see Figure 2 In order to detect darkness or dimness in the environment of the vehicle 1, an ambient brightness sensor 31 is provided, which supplies a corresponding signal to an actuation device 32 for the light source 8. The actuation device 32 for the light source 8 is preferably also used to actuate the light source of the headlight 2.

[0026] The optical waveguide 11 has correspondingly concentrated outcoupling elements in its interior and / or has a certain number and distribution of outcoupling elements on its back side 30, so as to ensure, on the one hand, total reflection of the coupled-in light on the flat front side 13 of the optical waveguide 11 and on the flat back side 30 which preferably extends parallel to the front side 13, wherein the coupled-in light is divided into a first light component 28 and a second light component 29.

[0027] Since the first color particles 19 and the second color particles 20 are arranged in the viscous carrier medium 33 of the microcapsule 18 (the microcapsule has a solid or flexible transparent outer skin 34), when the electric field is stopped, the color particles 19, 20 remain in the desired positions on the opposite sides 22 and 24 of the microcapsule 18. The distribution of the color particles 19, 20 is "frozen" and fixed after the color particles 19, 20 are oriented by the electric field. Therefore, color excitation or color adjustment is carried out by the electric field, which is permanent. Of course, the carrier medium 33 is configured to be transparent, so that a color effect can be achieved by the color particles 19, 20 dispersed in the carrier medium 33.

[0028] According to an alternative embodiment of the invention (not shown), a magnetic field or an electromagnetic field can also be used for color excitation. This depends on the type of color particles 19 , 20 or microcapsules 18 .

[0029] According to an alternative embodiment not shown, the microcapsule 18 can also have two or more different types of color particles, for example, first color particles of a first color, second color particles of a second color, third color particles of a third color, and fourth color particles of a fourth color as required. By applying an external field to excite these color particles with different electric or magnetic charges accordingly, these color particles can be mixed on the first side 22 of the microcapsule 18, so that color mixing occurs depending on the size of the external field. Therefore, based on three or four different color particles of different colors, for example cyan, magenta, yellow and white or black and white and red or black and white and yellow, the display 9 can be in different colors. For example, the composition of the color particles can be used to make the color impression of the display 9 have the color impression of the adjacent body component 16.

[0030] According to Figure 3 In the second embodiment of the present invention, the luminous surface unit 7' can be formed only by the electrophoretic display 9. There is no optical waveguide. The light source 11 is arranged in the region of the opposite narrow sides 35 of the luminous surface unit 7' or the electrophoretic display 9 for illuminating the electrophoretic display 9 in dim or dark conditions. In the present embodiment, the luminous surface unit 7' is therefore arranged recessed relative to the vehicle skin 14 of the body component 6. The depth of the luminous surface unit 7' is less than the depth of the recess 5.

[0031] According to an alternative embodiment of the invention (not shown), the lighting device can also be used for contour lighting in a decorative element in the interior of the vehicle 1 instead of in the body component.

[0032] If anodes and cathodes for generating an electric field are additionally arranged in the body component 6 or the decorative component, the color impression can also be changed during the operation of the lighting device 3 by corresponding control. Thus, a specific ambient lighting can be generated in the interior of the vehicle 1. The field that excites the color can be an electric field, a magnetic field or an electromagnetic field. The orientation of the field preferably extends perpendicularly to the main irradiation direction H, so that components passing through the field do not block the electrophoretic display 9. Reference numerals list

[0033] 1 Vehicle

[0034] 2 headlights

[0035] 3 lighting fixtures

[0036] 4 Radiator grille

[0037] 5 recesses

[0038] 6 Body components

[0039] 7, 7' light emitting surface unit

[0040] 8 Light Source

[0041] 9 Electrophoretic Display

[0042] 10Bottom

[0043] 11 Photoconductor

[0044] 12 Front

[0045] 13 Front

[0046] 14 Vehicle skin

[0047] 15 base

[0048] 16 Protective cover

[0049] 17 pixels

[0050] 18 microcapsules

[0051] 19First color particles

[0052] 20 Second color particles

[0053] 21 Anode

[0054] 22 First side

[0055] 23 cathode

[0056] 24 Second side

[0057] 25 narrow side

[0058] 26 PCB

[0059] 27 Sidewall

[0060] 28 First light component

[0061] 29 Second light component

[0062] 30 Back

[0063] 31 Ambient brightness sensor

[0064] 32 Control device

[0065] 33 Carrier medium

[0066] 34 skin

[0067] 35 narrow side

[0068] H Main irradiation direction

Claims

1. A lighting device for a vehicle (1), comprising a luminous surface unit (7, 7') that can be fixed to a body component (6) and / or a decorative component of the vehicle (1) and a light source (8) for illuminating the luminous surface unit (7, 7'), characterized in that: The light-emitting surface unit (7, 7') comprises an electrophoretic display (9), which has a plurality of microcapsules (18) that can excite colors.

2. The lighting device according to claim 1, characterized in that: The luminous surface unit (7) comprises a light conductor (11) which covers the electrophoretic display (9) on the front side (12) of the electrophoretic display, and the light source (8) is arranged on a narrow side (25) of the light conductor (11), so that light emitted by the light source (8) can be coupled into the light conductor on the narrow side (25) of the light conductor (11).

3. The lighting device according to claim 2, characterized in that: The optical waveguide (11) has a rear side (11) facing the electrophoretic display (9), on which a portion (29) of the coupled-in light can be coupled out in the direction of the electrophoretic display (9), and the optical waveguide (11) has a front side (13) on a side facing away from the electrophoretic display (9), on which another portion (28) of the coupled-in light can be coupled out in a main irradiation direction (H) of the lighting device, and / or the portion (29) of the coupled-in light coupled out on the rear side (11) can be coupled out after being reflected on the electrophoretic display (9).

4. The lighting device according to any one of claims 1 to 3, characterized in that: The microcapsules (18) each have a plurality of different color particles (19, 20), so that by exciting the microcapsules (18) with a predetermined electric field, magnetic field, or electromagnetic field, first color particles (19) of a first color or second color particles (20) of a second color can be displaced to a side (22) of the microcapsules (18) facing the front side (12) of the electrophoretic display (9) and can be fixed in this position.

5. The lighting device according to any one of claims 1 to 4, characterized in that: The color particles (19, 20) are dispersed in a transparent viscous carrier medium (33), the viscosity of which is designed to be so high that the color particles (19, 20) remain in the positions they occupy within the microcapsules (18) when the excitation of the microcapsules (18) ceases.

6. The lighting device according to any one of claims 1 to 5, characterized in that: The microcapsule (18) has a plurality of first color particles (19) of a first color and a plurality of second color particles (20) of a second color and / or a plurality of third color particles of a third color and / or a plurality of fourth color particles of a fourth color, so that the position distribution of the first color particles (19) and the second color particles (20) and / or the third color particles and / or the fourth color particles on the first side (22) of the microcapsule (18) can be adjusted according to the excitation of the microcapsule (18) by an external field, so as to produce a predetermined mixed color on the front side (12) of the electrophoretic display (9).

7. The lighting device according to any one of claims 1 to 6, characterized in that: The microcapsules (18) are arranged on a substrate to form a plurality of image points (17), each of which has a number of microcapsules (18) that can be excited in color by a minimal portion of an external electric and / or magnetic field.

8. The lighting device according to any one of claims 1 to 7, characterized in that: The luminous area unit (7, 7') is elongated and extends along the edge of a body component (6) and / or a decorative part of the vehicle (1).

9. The lighting device according to any one of claims 1 to 8, characterized in that: The light source (8) can be switched on and off or dimmed according to a signal from an ambient brightness sensor (31).

10. The lighting device according to any one of claims 1 to 9, characterized in that: The microcapsules (18) are excited in such a way that the luminous area unit (7, 7') emits light of a color that corresponds to an adjacent body component (6) of the vehicle (1).

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