Patent Application
20240337361
This application claims priority to European Patent Application No. 23166618.1, filed Apr. 4, 2023, which is incorporated herein by reference.
The invention relates to a lighting device for a vehicle headlamp, said lighting device is configured to generate different light distributions, wherein the lighting device comprises:
The invention further relates to a light module for a vehicle headlamp, comprising a lighting device and a secondary lighting device.
The invention also relates to a vehicle headlamp comprising a lighting device or a light module.
In the prior art, lighting devices for generating different light distributions and which comprise light sources and a corresponding lens system are known. Usually, light from light sources is pre-formed by a collimator device before said light gets emitted towards the lens system, which is configured to project said light coming from the collimator device in form of a light distribution, e.g. into a traffic space in front of the lighting device. It is also known to use multiple collimator devices which correspond to different light sources respectively, in order to create different light distributions. For example, a first collimator corresponds to a first light source and creates a first light distribution in conjunction with the lens system, and a second collimator corresponds to a second light source and creates a second light distribution in conjunction with the lens system. A drawback of those systems is the complex construction and the large number of optical components needed to create different light distributions.
It is an object of the invention to provide a lighting device for a vehicle head lamp, which is capable of creating different light distributions and also has a simplified yet effective constriction.
This object is achieved by a lighting device according to claim 1. Preferred embodiments are described in dependent claims.
According to a first aspect of the invention, the first lens element and the second lens element are configured and arranged to each other, such that their optical axes are aligned co-axial and that the first lens element and the second lens element create a common focal point, which lies in a common focal plane, which is located on a, the second lens element averting, side of the first lens element,
This has the advantage of creating a complete or partial, preferably adaptive, high beam light distribution, wherein the first section of the high beam light distribution, which is essentially generated by light being refracted by the refraction elements forming the sub-area, creates a smooth light intensity fade out below the H-H line or, in other words, a light spread below the H-H line. Therefore, in the forefield of the light distribution, i.e. an area closer to the lighting device compared to the far field, a transition between an illuminated area and a non-illuminated area is smoother. In other words, the invention provides a blurred high beam light distribution, wherein the blurring takes place in an area close to the lighting device or in a section of the light distribution which is vertically lower than the H-H line. Each light source of the first light source row emits a light bundle, which all together form a first light bundle row, wherein each light source of the second light source row emits a light bundle, which together form a second light bundle row. The lighting device can comprise more than two lens elements, e.g. a third or more lens element. In this disclosure, the term “refraction” is defined as a change of the propagation direction of a light bundle or light rays, after traversing an optical element, e.g. the first lens element. The term “downstream” is defined as along the direction of light propagation. Preferably, light sources of the first light source group and light sources of the second light source group are operable on two modes, an active/ON mode (in which light gets emitted from the light sources) and an inactive/OFF state (in which no light gets emitted from the light sources). Preferably, the first section of the high beam light distribution overlaps at least partially with the second section of the high beam light distribution, said overlap can be measures e.g. on an ECE 25 m test screen. The first section of the high beam light distribution may overlap with a lower portion of the second section, wherein said lower portion of the second section is located below the H-H line. Preferably, the light module is configured to generate different sections of a segmented light distribution or different segmented light distributions. Preferably, the light source holder can be (and therefore also the plurality of light sources) very close to the light receiving surface of the first lens element, e.g. a normal distance (along the main beam direction) between the plurality of light sources and the light receiving surface of the first lens element can be smaller than the width (or thickness) of the first lens element along its optical axis. Preferably, the normal distance (along the main beam direction) between the plurality of light sources (or the light source holder) and the light receiving surface of the first lens element can be smaller than the normal distance between the light emitting surface of the first lens element and a light receiving surface of the second lens element. The plurality of light sources can be disposed at a light source surface of the light source holder, wherein the light source surface lies essentially within the common focal plane. Preferably, the first section of the high beam light distribution comprises a first sub-section, with an intensity maximum, corresponding to light from the first light source group refracted by the sub-area, and a second sub-section, with an intensity maximum, corresponding to light from the first light source group refracted by the main-area. Due to the stronger refraction by the sub-area, the intensity maximum of the first sub-section can be vertically lower than the intensity maximum of the second sub-section. Preferably, the second section of the high beam light distribution comprises a first sub-section, with an intensity maximum, corresponding to light from the second light source group refracted by the sub-area, and a second sub-section, with an intensity maximum, corresponding to light from the second light source group refracted by the main-area. Due to the stronger refraction by the sub-area, the intensity maximum of the first sub-section can be vertically lower than the intensity maximum of the second sub-section. The first fraction of light from the first light source group (as well as the second light source group) can be larger or smaller than the second fraction, depending on the position of the first (or second) light source group relative to the light receiving surface of the first lens element.
Advantageously, the light sources of the first light source group are disposed along a first row on the light source holder and light sources of the second light source group are disposed along a second row on the light source holder, wherein the second row is essentially parallel to the first row.
Advantageously, the first light source group and the second light source group are oriented on the light source holder—in the installation position—along horizontal lines respectively.
Advantageously, the refraction elements are formed as prismatic elements, having an essentially triangular cross-section, in the installation position, along a vertical sectional plane, wherein preferably each prismatic element has a longitudinal extension, which is orthogonal to the optical axis and preferably oriented horizontally.
Advantageously, the refraction elements are formed as recesses or protrusions within the light receiving surface of the first lens element, wherein preferably the sub-area is surrounded by the main-area.
Advantageously, the intensity maximum of the first illuminated area, formed by refracted light by the sub-area, is located below a H-H line in an Isolux-diagram. In this disclosure, the H-H line in an Isolux-diagram is in accordance with the ECE regulations regarding vehicle headlamps, in which an illumination produced by a vehicle headlamp shall be checked on a vertical screen set at a distance of 25 m in front of the headlamp and at right angles to its axis.
Advantageously, the intensity maximum of the second illuminated area, formed by refracted light by the main-area, is located essentially at or above a H-H line in an Isolux-diagram.
Advantageously, each light source of the first light source group and each light source of the second light source group is individually controllable, depending on an operation mode of the lighting device.
Advantageously, the plurality of light sources comprise a third light source group, which is disposed vertically lower than the second light source group, wherein light from the third light source group is emitted essentially towards the main-area, wherein refracted light from the third light source group corresponds to a third illuminated area, which forms a third section of the high beam light distribution, wherein said third section has a third intensity maximum, wherein refraction of light from the third light source group by the main-area is such that the third intensity maximum is vertically higher than the first intensity maximum and the second intensity maximum in front of the lighting device.
Advantageously, the third light source group is disposed in a third row on the light source holder, preferably oriented along a horizontal line, parallel to the second row, wherein the third row is vertically lower than the second row.
Advantageously, the lighting device comprises a shade element, preferably disposed—in the installation position—vertically above the first lens element, said shade element is configured to block the first fraction of light from the second light source group, which entered the first lens element via the sub-area, from traversing towards the second lens element.
Advantageously, the plurality of light sources are disposed at a light source surface of the light source holder, wherein the light source surface lies essentially within the common focal plane.
According to a second aspect of the invention, a light module for a vehicle headlamp is provided, said light module is configured to generate different light distributions, each correlating to a different operation mode of the light module, wherein the light module comprises a lighting device and a secondary lighting device, configured to create a portion of a low beam light distribution, wherein the light module is configured to operate in at least two operation modes, wherein:
Advantageously, the second portion of the asymmetric low beam light distribution, which is created by the secondary lighting device, forms a light-dark boundary of the asymmetric low beam light distribution.
According to a third aspect of the invention, a vehicle headlamp is provided, comprising a lighting device or a light module.
In the following, in order to further demonstrate the present invention, illustrative and non-restrictive embodiments are discussed, as shown in the drawings, which show:
In the shown embodiment, the light sources of the first light source group 2a are disposed along a first row on the light source holder 2h and the light sources of the second light source group 2b are disposed along a second row on the light source holder 2h, wherein the second row is essentially parallel to the first row. The first light source group 2a and the second light source group 2b (or in other words the first row of light sources and the second row of light sources) are oriented on the light source holder 2h—in the installation position—along horizontal lines respectively.
Preferably, each light source of the first light source group 2a and each light source of the second light source group 2b is individually controllable, depending on an operation mode of the lighting device 1, or depending on what section of a segmented light function shall be illuminated.
The lighting device 1 comprises a first lens element 3, arranged downstream of the plurality of light sources 2 along the main beam direction d. The first lens element 3 comprises a light receiving surface 3a, facing the plurality of light sources 2, and a light emitting surface 3b, opposite of the light receiving surface 3a. The first lens element 3 is configured to receive light from the plurality of light sources 2 via the light receiving surface 3a and to emit received light via the light emitting surface 3b. The first lens element 3 has an optical axis x1. The first lens element 3 is configured to refract light, in respect to its optical axis x1.
The lighting device 1 comprises a second lens element 4, arranged downstream of the first lens element 3 along the main beam direction d, configured to receive refracted light from the first lens element 3 and to project said light in front of the lighting device 1. The second lens element 4 has an optical axis x2.
The first lens element 3 and the second lens element 4 are configured and arranged to each other, such that their optical axes x1, x2 are aligned co-axial and that the first lens element 3 and the second lens element 4 create a common focal point f. The common focal point f lies in a common focal plane fp, which is located on a, the second lens element 4 averting, side of the first lens element 3.
The plurality of light sources 2 are disposed on a light source holder 2h. The light source holder 2h is disposed relative to the first lens element 3 and the second lens element 4, such that the main beam direction d of light emitted by the plurality of light sources 2 is essentially parallel to the optical axis x1 of the first lens element 3 and the optical axis x2 of the second lens element 4. In the shown embodiment, the distance between the light source holder 2h and the first lens element 3 is smaller than the distance between the first lens element 3 and the second lens element 4.
As depicted in
As depicted in
The first light source group 2a, the second light source group 2b, the first lens element 3 and the second lens element 4 are configured to create a complete or partial, preferably adaptive, high beam light distribution. Said high beam light distribution is formed by at least two sections HB1, HB2 (see
Furthermore, the refracted first fraction and second fraction of light from the second light source group 2b correspond to a second illuminated area, which forms a second section HB2 of the high beam light distribution HB.
The first section HB1 has a first intensity maximum and the second section HB2 has a second intensity maximum. The refraction of light by the sub-area 5a and the refraction of light by the main-area 5b is such that the first intensity maximum of the first section HB1 is vertically lower in front of the lighting device 1 than the second intensity maximum of the second section HB2 of the high beam light distribution.
In the shown embodiment, the plurality of light sources 2 comprise a (optional) third light source group 2c, which is disposed vertically lower than the second light source group 2b. Light from the third light source group 2c is emitted, preferably essentially only, towards the main-area 5b. Refracted light from the third light source group 2c corresponds to a third illuminated area, which forms a third section HB3 of the high beam light distribution HB. The third section HB3 has a third intensity maximum. The refraction of light from the third light source group 2c by the main-area 5b is such that the third intensity maximum is vertically higher than the first intensity maximum and the second intensity maximum in front of the lighting device 1. The third light source group 2c is disposed in a third row on the light source holder 2h, preferably oriented along a horizontal line, parallel to the second row, wherein the third row is vertically lower than the second row.
Preferably the lighting device 1 may comprise a shade element 12 (depicted in
In
By “stacking” or combining the illuminated areas shown in
In
In
In
As known to a person skilled in the art, the subsequent second lens element 4 is configured to invert the light coming from the first lens element 3, when projecting the light into a traffic space. As a result, the vertically lowest illumination of the light receiving surface 3a, i.e.
In a first operation mode of the light module 10, the first light source group 2a and the second light source group 2b of the lighting device 1 are active and configured to create a complete or partial, preferably adaptive, high beam light distribution in conjunction with the first lens element 3 and the second lens element 4, wherein the secondary lighting device 11 is inactive.
In a second operation mode of the light module 10, a first portion of the first light source group 2a is active and a second portion of the first light source group 2a and the second light source group 2b is inactive. In the second operation mode the active first light source group 2a, the first lens element 3 and the second lens element 4 are configured to create a first portion of an asymmetric low beam light distribution, wherein a first illuminated area, which is created by refracted light from the active first portion of the first light source group 2a by the sub-area 5a, and preferably also by the main-area 5b, corresponds to the first portion of the asymmetric low beam light distribution.
The secondary lighting device 11 is configured to create (by means of a light source unit 11a and an optical device 11b, comprising e.g. a collimator and an optical element, corresponding to the light source unit 11a) a second portion of an asymmetric low beam light distribution. The first portion and the second portion form the asymmetric low beam light distribution, preferably the first portion forms an asymmetric portion of the asymmetric light distribution, which illuminates an area on the driving side of a vehicle, when the light module 10 is installed in a vehicle.
The second portion of the asymmetric low beam light distribution, which is created by the secondary lighting device 11, can form a light-dark boundary of the asymmetric low beam light distribution.
In the embodiment shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 23166618.1 | Apr 2023 | EP | regional |
