Lighting device for a motor vehicle

Abstract

Lighting device for a motor vehicle, in particular a headlight for a motor vehicle, comprising - at least one light source (1) from which light (4) is emitted during the operation of the light source, - an optical component (2) into which light (4) emitted by the at least one light source (1) enters, - Light-controlling means (9) with an active surface for selectively controlling individual pixels or groups of pixels of the light (4), wherein the light-controlling means (9) reflect or deflect incident light (4) in such a way that it at least partially exits the lighting device, - Lighting optics formed on or in the optical component (2), and the light (4) from the lighting optics is reflected or deflected onto the active surface of the light-controlling means (9) during operation of the lighting device, wherein the light-controlling means (9) are arranged outside the optical component (2) such that light (4) emanating from the lighting optics exits the optical component (2), strikes the active surface of the light-controlling means (9), is reflected or deflected by the latter, and then re-enters the optical component (2), characterized in that the light-controlling means (9) are in direct or indirect contact with an outer surface of the optical component (2), wherein a connecting layer (8) is arranged between the outer surface of the optical component (2) and the light-controlling means (9).and wherein the connecting layer (8) is designed to reduce light loss.

Description

[0001] The present invention relates to a lighting device for a motor vehicle, in particular a headlight for a motor vehicle, according to the preamble of claim 1.

[0002] State-of-the-art high-resolution headlight projection modules utilize a large number of optically relevant components that must be precisely aligned. These include, for example, light-control devices that serve as imaging elements, such as a digital micro-mirror device (DMD) or an LCoS (liquid crystal on silicon) or LCD display, as well as illumination optics for lighting the imaging element. The imaging element can specifically reflect, shade, or deflect light from individual pixels or groups of pixels in such a way that at least part of it escapes from the illumination device. Furthermore, decoupling optics are typically used to project an active surface of the light-control devices onto the road surface.

[0003] A lighting device of the type mentioned above is known from US 2010 / 0208478 A1. The vehicle headlight system described therein comprises a light source, a total internal reflection prism, a digital reflector, a freeform lens, and a multi-curve reflector. The total internal reflection prism serves to deflect and reflect light rays from the light source. The digital reflector is controlled to switch between several states with respect to the light rays reflected by the total internal reflection prism, whereupon compensation patterns are immediately output in the different states. The freeform lens serves to control the directions of the light rays from the digital reflector. The multi-curve reflector has several radii of curvature to reflect the light rays from the freeform lens.

[0004] A lighting module for vehicles is known from the subsequently published WO 2019 / 105588 A1. The lighting module comprises a light source, a pixel-based digital imaging system, and an optical input device arranged along the beam path of the rays emanating from the light source between the light source and the pixel-based digital imaging system to transmit a portion of the rays emanating from the light source to the pixel-based digital imaging system. The lighting module further comprises a prism with a first, a second, and a third face, configured to transmit rays of the portion transmitted to an impact surface between the first and third faces, to generate rays reflected by total internal reflection at the first face of the rays reflected back from the impact surface, and to reflect reflected rays back via the second face.

[0005] A lighting unit is known from the subsequently published DE 10 2019 207 699 A1. The lighting unit comprises a reflection device in which a micromirror arrangement is selectively operated to selectively reflect incident light, wherein the micromirror arrangement is an arrangement of micromirrors arranged in a matrix; a projection lens that reflects the light selectively reflected by the reflection device forward in a light distribution pattern; and a suppression element configured to suppress a compression of the light incident on the projection lens in an area other than the micromirror arrangement in order to suppress a temperature increase of the area.

[0006] Another lighting device is known from DE 10 2018 115 045 A1. The lighting device described therein can be designed as a high-resolution spotlight. The lighting device comprises two monolithic components made of a transparent material, one of which serves as the lighting optics and the other as the decoupling optics.

[0007] The illumination device also includes a digital micromirror device that serves as an imaging element and is located between the first monolithic component and the second monolithic component.

[0008] The purpose of the present invention is to create a lighting device of the type mentioned above which has a smaller number of optical components.

[0009] According to the invention, this is achieved by means of a lighting device of the type mentioned at the outset, having the characterizing features of claim 1. The dependent claims relate to preferred embodiments of the invention.

[0010] Claim 1 provides that the light-modifying means are in direct or indirect contact with an outer surface of the optical component, wherein a connecting layer is arranged between the outer surface of the optical component and the light-modifying means, and wherein the connecting layer is configured to reduce light losses.

[0011] In contrast to the prior art, the invention reduces the setup effort for the lighting device. In particular, a high-resolution headlight projection module can be implemented with a smaller number of components.

[0012] The light-modifying agents can be in direct or indirect contact with a light-refracting surface of the optical component, allowing light to pass through and enter the optical component. The bonding layer may be made of liquid silicone rubber (LSR).

[0013] The light-controlling means can be designed as a digital micromirror device, an LCoS display, or an LCD display, or they can comprise a digital micromirror device, an LCoS display, or an LCD display. The light-controlling means can be designed to reflect portions of the light emitted by the optical component back to the optical component. An example of this is a reflective LCD display.

[0014] The lighting optics may comprise a reflector with a single uninterrupted mirror surface or a plurality of mirror elements. For example, the reflector may have a concave, curved base. Preferably, the reflector may be formed by a reflective surface of the optical component, which may, in particular, have at least one reflective layer applied to the outside of the component. The optical component may be compactly dimensioned by folding the beam path within the optical component as a result of reflection.

[0015] The lighting device preferably comprises decoupling optics through which light emitted by the influencing means exits the lighting device during operation. The decoupling optics can be integrated into the optical component, in particular by means of a refractive exit surface of the optical component. The exit surface can be aspherically curved and / or designed as a freeform surface. By integrating the decoupling optics into or on the optical component, the number of parts of the lighting device that need to be aligned is further reduced.This is the first time that a combination of lighting optics, an imaging element and decoupling optics has been combined on or in a single prefabricated component, eliminating the need to align multiple optically relevant components during final headlight assembly.

[0016] It is possible that the optical component is a monolithic component made of, for example, glass or polycarbonate (PC). A prefabricated monolithic or one-piece component is robust and compact.

[0017] It is possible for at least one light source to be a laser light source, in particular a semiconductor laser, or a light-emitting diode. It is also possible to use multiple semiconductor lasers or multiple light-emitting diodes, or to combine at least one semiconductor with at least one light-emitting diode.

[0018] The invention is explained in more detail below based on the accompanying drawings. It shows Fig. 1 a schematic view of a lighting device according to the invention.

[0019] The illustrated example of a lighting device comprises a light source 1, which is designed in particular as a semiconductor laser or a light-emitting diode. It is possible to provide more than one semiconductor laser and / or more than one light-emitting diode.

[0020] The lighting device also includes a monolithic component 2, made of glass or polycarbonate, for example. The optical component 2 has a refractive entrance surface 3 through which the light 4 emitted by the light source 1 can enter the optical component 2.

[0021] On the side of the optical component 2, opposite the entrance surface 3, a reflector 5 is arranged, which is in particular designed as a faceted reflective region with a plurality of mirror elements 6. However, it is possible to provide the reflector 5 with a single, uninterrupted mirror surface.

[0022] Preferably, the reflector 5 can be formed by a reflective surface of the optical component 2, which in particular can have at least one reflective layer attached to the outside of the component 2.

[0023] The reflective component forming reflector 5 can be curved, in particular concave, or flat.

[0024] The light-refracting entrance surface 3 and the reflector 5 form the lighting optics, from which the light 4 emitted by the light source 1 is directed onto the light-controlling means 9 described in detail below.

[0025] The reflector 5 is inclined such that the light 4 from the reflector 5 is directed onto a refractive surface 7 of the optical component 2, which is different from the entrance surface 3. The light-modifying elements 9 are coupled to the outside of this refractive surface 7. The coupling of the light-modifying elements 9 is achieved via a bonding layer 8, which is arranged between the refractive surface 7 and the light-modifying elements 9. The bonding layer can, for example, consist of liquid silicone rubber (LSR).

[0026] The light-modifying elements 9 serve as an imaging element and can be designed, for example, as a digital micromirror device (DMD), an LCoS (Liquid Crystal on Silicon), or an LC display. An active surface of the light-modifying elements 9 is designed to reflect parts of the light 4 emitted by the refractive surface 7 back to the refractive surface 7.

[0027] The refractive surface 7 couples the portions of the light 4 reflected by the active surface of the light-controlling device 9 back into the optical component 2. A refractive exit surface 10 of the optical component 2 is arranged on the side of the optical component 2 opposite the surface 7, which serves as decoupling optics. The exit surface 10, for example, can be aspherically curved and / or designed as a freeform surface. The exit surface 10 projects the active surface of the light-controlling device 9 onto a projection plane 11 in the traffic area. Reference symbol list 1 light source 2 optical components 3 Entrance area 4 Light emitted by the light source 5 Reflector 6 mirror element 7 light-refracting surface 8. Compound layer 9 Light-modifying agents 10 Exit area 11 Projection plane

Claims

[1] Lighting device for a motor vehicle, in particular a headlight for a motor vehicle, comprising - at least one light source (1) from which light (4) is emitted during the operation of the light source, - an optical component (2) into which light (4) emitted by the at least one light source (1) enters, - Light-controlling means (9) with an active surface for selectively controlling individual pixels or groups of pixels of the light (4), wherein the light-controlling means (9) reflect or deflect incident light (4) in such a way that it at least partially exits the lighting device, - Lighting optics formed on or in the optical component (2), and the light (4) from the lighting optics is reflected or deflected onto the active surface of the light-controlling means (9) during operation of the lighting device, wherein the light-controlling means (9) are arranged outside the optical component (2) such that light (4) emanating from the lighting optics exits the optical component (2), strikes the active surface of the light-controlling means (9), is reflected or deflected by the latter and then re-enters the optical component (2), characterized by, that the light-modifying means (9) are in direct or indirect contact with an outer surface of the optical component (2), wherein a connecting layer (8) is arranged between the outer surface of the optical component (2) and the light-modifying means (9), and wherein the connecting layer (8) is configured to reduce light losses. [2] Lighting device according to claim 1, characterized by , that the light-controlling means (9) are in direct or indirect contact with a light-refracting surface (7) of the optical component (2) through which light (4) can exit the optical component (2) and enter the optical component (2). [3] Lighting device according to one of claims 1 or 2, characterized by , that the bonding layer (8) is made of liquid silicone rubber (LSR). [4] Lighting device according to any one of claims 1 to 3, characterized by, that the light-controlling means (9) are designed as a digital micromirror device or as an LCoS or as an LC display, or that the light-controlling means (9) comprise a digital micromirror device or an LCoS or an LC display. [5] Lighting device according to any one of claims 1 to 4, characterized by that the lighting optics comprise a reflector (5) with a single uninterrupted mirror surface or a plurality of mirror elements. [6] Lighting device according to claim 5, characterized by , that the reflector (5) has a concave, curved base. [7] Lighting device according to one of claims 5 or 6, characterized by , that the reflector (5) is formed by a reflective surface of the optical component (2), which in particular may have at least one reflective layer attached to the outside of the optical component (2). [8] Lighting device according to any one of claims 1 to 7, characterized by , that the lighting device includes a decoupling optic through which light (4) emitted by the light-controlling means (9) escapes from the lighting device during operation. [9] Lighting device according to claim 8, characterized by , that the decoupling optics are integrated into the optical component (2), in particular by means of a light-refracting exit surface (10) of the optical component (2). [10] Lighting device according to claim 9, characterized by , that the exit surface (10) is aspherically curved and / or designed as a freeform surface. [11] Lighting device according to any one of claims 1 to 10, characterized by , that the optical component (2) is a monolithic component. [12] Lighting device according to any one of claims 1 to 11, characterized by, that the optical component (2) consists of glass or polycarbonate (PC). [13] Lighting device according to any one of claims 1 to 12, characterized by , that the at least one light source (1) is a laser light source, in particular a semiconductor laser, or a light-emitting diode.

Images