Improved light-emitting module for a vehicle headlight

Abstract

The invention concerns a light-emitting module (100) for a vehicle, comprising a light source unit (120), a light-reflecting device (140) and a lens (160). The light-reflecting device comprises a total internal reflecting unit (142) to reflect the light emitted by the light source unit, and a transparent unit (144). The lens comprises a light-entry lens surface (162) and an optical axis. The transparent unit (144) has a minimum length of 6 mm along the direction of the optical axis of the lens (160). The light-entry lens surface comprises at least two lens regions, with different focal points, along a direction perpendicular to the optical axis of the lens (160). The light source unit (120) comprises at least two light source regions in the direction perpendicular to the optical axis of the lens (160), with light emitted from each light source region being directed towards a respective lens region.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to the technical field of light-emitting modules for use in vehicles.BACKGROUND OF THE INVENTION

[0002] Various light-emitting modules for vehicles are known in the prior art to produce an illuminating beam, a signaling beam, or a combination of both.

[0003] In the conventional design of light-emitting modules, to produce at least an illuminating beam, a light source emits a light, and a light-reflecting device (comprising a total internal reflecting unit) is configured to reflect all the light emitted by the light source into parallel and / or convergent beams, towards a lens. The illuminating beam exiting the lens forms a light distribution pattern. The light distribution pattern is typically measured on a surface located 25 m from the light source in a standard test of the light-emitting module in the field of vehicle testing. It is illustrated as an iso-lux diagram, the contours of which represent the points of equal illuminance in lux. The standard test and the iso-lux diagram are known to a person skilled in the art.

[0004] The light distribution pattern must conform to certain regulations for vehicle illuminating beams, such as UN Regulation No. 149 - Road Illumination Devices (RID). According to the requirements of the regulation, firstly, the light distribution should achieve a specified luminance. Secondly, it should conform to certain dimensional requirements, such as width. Thirdly, it should be homogeneous. A homogeneous light distribution is defined as an iso-lux diagram the contours of which have a more or less regular distribution density. Further details are not provided here. Similarly, in the following description, the terms "homogeneous light" and "homogenize the light" are to be understood in the same way as a homogenous light distribution.

[0005] In practice, the light exiting the total internal reflecting unit of the light-reflecting device is far from being homogeneous. To solve this problem, the existing modules has the light propagate through an empty space, i.e., in the air, between the light-reflecting device and the main focal point of the lens. Typically, a minimum distance of about 30 to 50 mm is required for the light to propagate in the air before reaching the main focal point of the lens to ensure a homogenous light distribution according to the regulation. This distance also helps achieve the width of the light distribution required by the regulation. Consequently, the shortest distance from a light-exit surface of the light-reflecting device to the main lens focal point typically ranges between 30 and 50 mm, and the shortest distance from the light source to a main lens focal point typically ranges between 40 and 60 mm. Additionally, the back focal length of the lens ranges typically from 30 to 50 mm, for example, 40 mm. The back focal length is defined as the distance between the focal point of the lens and the center of the surface where the light emitted by the light source enters the lens. This surface is also called a light-entry lens surface.

[0006] If these distances are shorter than the specified ranges, the light distribution may result in an inadequate luminance, non-conforming dimensions or lack of homogeneity, leading to suboptimal illumination performance. Consequently, for front fog lamps, low beam headlights, high beam headlights, and combined high and low beam headlights, the conventional design typically results in a total length of the light-emitting module exceeding 100 mm.

[0007] In addition, for a low beam or a front fog lamp, a cut-off line in the light distribution is required by the regulation. In conventional designs, this necessitates a shutter, separate from other components of the light-emitting module, to be positioned between the light-exit surface of the light-reflecting device and the main focal point of the lens. This placement of the shutter creates the required cut-off line in the light distribution. Therefore, the manufacturing process becomes more complicated due to the involvement of an additional component.

[0008] In recent years, with the developing trend of vehicle styling, especially with the booming development of electric vehicles, more requirements have been placed on the shape and size of the light-emitting modules, which are an important element of front-end and rear-end styling. For instance, for electric vehicles without a front grille, it is advantageous from a styling perspective to arrange the light-emitting modules at the front of the vehicle in the most compact manner possible, particularly in the vehicle's longitudinal direction, i.e., the X-direction. Similarly, a compact design in the longitudinal direction is also highly required for the motorcycles.

[0009] In order to shorten the overall length of the light-emitting module in the X-direction, some existing designs position at least two lenses in a row along the optical axis of the lens (typically parallel to the X-direction). This arrangement shortens the focal length of the set of lenses while still meeting the requirements of the regulation for light distribution. However, this solution significantly increases the manufacturing costs and reduces the optical efficiency of the light-emitting module.

[0010] In other words, the prior art light-emitting modules struggle to meet the new dimensional requirements in the X-direction of the vehicle while satisfying the functional requirements and without increasing the manufacturing costs. Therefore, further improvements to the existing light-emitting modules are necessary.SUMMARY OF THE INVENTION

[0011] The present invention aims to overcome the shortcomings of the prior art by providing a light-emitting module for a vehicle with smaller total length, whilst maintaining the light distribution according to the requirements of the regulation and not increasing manufacturing costs. It is important to note that in the present description, the term "length" always refers to the length along the optical axis of the lens of the light-emitting module, which in most cases coincides with the X-direction of the vehicle as previously defined.

[0012] The light-emitting module in the present invention can be used in various types of vehicle lamps, including but not limited to, front fog lamps, low beam headlights, high beam headlights, and combined high and low beam headlights.

[0013] To this end, the invention relates to a light-emitting module for a vehicle, comprising: a light source unit emitting light, a light-reflecting device comprising a first part and a second part, wherein the first part is a total internal reflecting unit configured to reflect all the light emitted by the light source unit into parallel and / or convergent beams, and the second part is a transparent unit directly connected to the total internal reflecting unit and having a light-exit surface, a lens having an optical axis, comprising a light-entry lens surface and a light-exit lens surface, wherein the transparent unit of the light-reflecting device has a minimum length of 6 mm along the direction of the optical axis of the lens, the light-entry lens surface comprises at least two lens regions along a direction perpendicular to the optical axis of the lens, with the at least two lens regions having different focal points, the light source unit comprises at least two light source regions in the direction perpendicular to the optical axis of the lens, each light source region comprising at least one light source, with light emitted from each light source region being directed towards each lens region respectively.

[0014] Firstly, thanks to the transparent unit having a length of at least 6 mm, it homogenizes the light more efficiently than air. This ensures that the light is sufficiently homogenized, as required by the regulation, over a shorter distance within the transparent unit, instead of through the air like in the prior art. Consequently, the light-exit surface of the transparent unit can be positioned in close proximity to a main focal point of the lens, for example, at a distance from the main focal point ranging between 0 and 2 mm.

[0015] Secondly, the design features at least two lens regions, each with its own focal point corresponding to a respective light source region. This arrangement maintains the required width of the light distribution, according to the regulation, while allowing the light sources to be placed closer to the lens than in the prior art. Additionally, the combination of the above two features has a synergistic effect, allowing to significantly reduce the total length of the light-emitting module to, for example, approximately 55 mm, compared to over 100 mm in the prior art.

[0016] According to preferred embodiments, the light-emitting module for a vehicle according to the invention may further comprise the following features, implemented separately or in each of their technically operative combinations.

[0017] Advantageously, the light-emitting module comprises a lens holder extending along the direction of the optical axis of the lens, with the lens being fixed to the lens holder. The lens holder supports the lens and blocks the stray light.

[0018] According to a preferred embodiment, the lens holder and the light-reflecting device are made in one-piece.

[0019] Preferably, the lens holder comprises at least one separating wall extending along the direction of the optical axis of the lens separating the at least two lens regions. The number of separating walls equals to the number of lens regions minus one.

[0020] The separating wall is used to channel light emitted from at least two light source regions into their respective lens regions without contamination from neighboring region(s). It also serves to block stray light reflected by the total internal reflecting unit, resulting in a more refined final light distribution.

[0021] Advantageously, the separating wall(s) and / or said lens holder comprising said separating wall(s) are made of a light-absorbing material, such as black polycarbonate (PC).

[0022] According to a preferred embodiment, the light-emitting module comprises a shutter integrated on a bottom surface of the transparent unit of the light-reflecting device. The bottom surface refers to the surface facing downward once the light-emitting module is installed on a vehicle. The shutter is for creating a cut-off line at the upper edge of the final light distribution to comply with the regulation.

[0023] For comparison, in conventional light-emitting modules, a separate shutter, typically made of metal, is positioned between the lens focal points and the light-reflecting device along the direction of the optical axis of the lens. In the present invention, integrating the shutter into the light-reflecting device reduces the number of optical components in the light-emitting module, lowers its weight, enhances compactness, and reduces manufacturing complexity and costs.

[0024] Advantageously, the shutter and the transparent unit are made in one piece. Preferably, the light-reflecting device is also made in one piece. The number of mounting parts and assembly steps is therefore reduced, simplifying the assembly of the light-emitting module and lowering manufacturing costs.

[0025] Advantageously, each light source region comprises at least one light source, each light source comprises at least one light-emitting diode (LED). The total internal reflecting unit comprises at least two total internal reflectors, each connected to a respective light source, configured to reflect all the light emitted by the light source into parallel and / or convergent beams.

[0026] According to a preferred embodiment, the light-entry lens surface comprises three lens regions, and the light source units comprises three light source regions. Advantageously, the three lens regions are composed of one central lens region having a main focal point, and two side lens region each having a side focal point which is aligned with the light source along the direction of the optical axis of the lens. For example, the three lens regions are composed of one central lens region having a back focal length ranging between 20 and 30 mm, preferably 27 mm, and two side lens regions each having a back focal length ranging between 50 to 60mm, preferably 51.5 mm.

[0027] Advantageously, according to the above embodiment, the lens holder comprises two separating walls and separating the three lens regions.

[0028] Preferably, the three light source regions are composed of a center light source region comprising one light source and two side light source regions each comprising two light sources. For example, the central light source region comprises one light source with at least one two-chip LED, while each side light source region comprises two light sources, each with one one-chip LED.

[0029] The invention also relates to a vehicle comprising at least one light-emitting module as described above.BRIEF DESCRIPTION OF THE FIGURES

[0030] The invention will be better understood upon reading the following description, provided only as an illustrative example. The terms "top", "bottom", "front" and "rear" refer to the directions once the light-emitting module is installed on a vehicle. The following description is with reference to the attached drawings in which: Figure 1 is a top view of the light-emitting module according to a particular embodiment of the invention, Figure 2 is a side view of the light-emitting module of Figure 1, Figure 3 is a perspective view of the light-emitting module of Figure 1, Figure 4 is an illustrative view depicting a first part of the optical path of the light-emitting module of Figure 1, Figure 5 is an illustrative view depicting a second part of the optical path of the light-emitting module of Figure 1, Figure 6 is a front view of the light-reflecting device of the light-emitting module of Figure 1, showing a front view of the light source unit through the transparent unit. DETAILED DESCRIPTION

[0031] Figures 1 to 3 illustrate a light-emitting module 100 for a vehicle (not shown) comprising a light source unit 120, a light-reflecting device 140 and a lens 160. In this example, the light-emitting module 100 is designed for low beam headlights, with the final light distribution conforming to low beam regulation. However, in other embodiments (not shown), the light-emitting module 100 could be designed to conform to the regulation of other types of beams, such as front fog lamps, high beam headlights, and combined high and low beam headlights.

[0032] The light source unit 120 comprises at least one light source 121, emitting a light 200, as depicted in Figures 4 and 5.

[0033] As illustrated in Figures 1 to 3, the light-reflecting device 140 comprises a total internal reflecting unit 142 and a transparent unit 144 which is directly connected to the total internal reflecting unit 142 in the direction of the optical axis D of the lens 160. The term "transparent" means that it is at least transparent to any light radiation having a wavelength comprised in the visible spectrum, that is to say, comprised between about 380 and 780 nm. In the present disclosure, "translucent" is not considered "transparent".

[0034] The total internal reflecting unit 142 is in contact with the light source unit 120. Typically, the total internal reflecting unit 142 contains total internal reflectors 1421, with each total internal reflector 1421 corresponding to each light source 121. These total internal reflectors are commonly made of reflective coated mirrors, and the inner surface of the total internal reflector 1421 is shaped as an ellipsoid, paraboloid, hyperboloid or a free-form surface.

[0035] The transparent unit 144 comprises a light-exit surface 146. The light-exit surface 146 may or may not be a continuous curve, designed to orient the light 200 at specific angles to achieve a final light distribution according to the regulations. The method for defining the geometry of the light-exit surface 146 is considered general knowledge to a person skilled in the art, hence, the details will not be provided here.

[0036] The lens 160 comprises a light-exit lens surface 164 and a light-entry lens surface 162.

[0037] In the present embodiment, the light-entry lens surface 162 is divided into three lens regions, 1621, 1622 and 1623, in a direction perpendicular to the optical axis D of the lens 160. The optical axes of these different regions are typically parallel to each other, so only one optical axis D is used to represent the direction of all the optical axes.

[0038] Preferably, the lens regions 1621, 1622 and 1623 can have different or identical dimensions and / or curvatures. As an example, the light-entry lens surface 162 in each lens region 1621, 1622 and 1623can be a single-curved surface or an undulated surface. A flexible design is possible according to custom requirements.

[0039] Dividing the light-entry lens surface 162 into regions allows reducing the thickness (in the direction of the optical axis) of the lens 160, the overall weight of the light-emitting module 100, and, consequently, its manufacturing costs.

[0040] The height and width of each lens region 1621, 1622 and 1623 preferably range between 10 and 30 mm, respectively. In the present embodiment, the total width of the lens 160 is 60 mm, and its height is 15 mm. The width corresponds to the Y direction as indicated in Figure 1, and the height corresponds to the Z direction. As a reference, once the light-emitting module 100 is installed on a vehicle, the X direction represents the longitudinal axis of the vehicle in the use position, Y direction represents the transverse axis of the vehicle, and the Z direction represents the vertical direction of the vehicle. In the embodiment shown in the Figures, the X direction coincides with the direction of the optical axis D of the lens.

[0041] In the present embodiment, each lens region measures 20 mm in width and 15 mm in height.

[0042] Each lens region 1621, 1622 and 1623 can have the same or different back focal lengths. Preferably, for a low beam light-emitting module, at least two regions have different back focal lengths. In the present embodiment, the central lens region 1622 has a back focal length of 27 mm, while each of the two side lens regions 1621 and 1623 have a back focal length of 51.5 mm. In addition, in the present embodiment, the thickness (in the direction of the optical axis) of the lens 160 measured in the center of the central lens region is 10 mm, while the thickness of the lens 160 measured in the center of each side lens region is about 3.5 mm.

[0043] The focal points can be positioned at different depths along the X direction. As illustrated in Figure 1, the central focal point A of the central lens region 1622 is located approximately at the light-exit surface 146 of the transparent unit 144 of the light-reflecting device 140, whereas focal points B and C of the side lens regions 1621 and 1623 are positioned at the level of the light sources 121 of the light source unit 120.

[0044] The selection of the focal lengths for the different lens regions 1621, 1622 and 1623 depends on regulatory requirements and specific custom preferences. The design of the present embodiment enables a center-concentrated beam in the final light distribution and optimizes the width of the overall light distribution.

[0045] Preferably, the light-emitting module 100 includes a lens holder 170 to securely hold the lens 160. The lens holder 170 is elongated along the optical axis of the lens 160. Advantageously, the lens holder 170 comprises side walls which serves to block stray light. In the present embodiment, advantageously, the lens holder 170 is divided into three regions corresponding to the three lens regions 1621, 1622 and 1623 by two separating walls 172. Preferably, the separating wall(s) 172 and / or the lens holder 170 are made of a light-absorbing material, such as black polycarbonate (PC).

[0046] In the present embodiment, the light source unit 120 comprises five light sources distributed across three light source regions, 1201, 1202 and 1203, corresponding to the three lens regions 1621, 1622 and 1623. The central light source region 1202 includes one light source 121, while each of the two side sources regions, 1201 and 1203, includes two light sources 121.

[0047] As illustrated in Figure 4, the light 200 emitted from the central light source region 1202 is reflected and focused by the total internal reflecting unit 142, propagating through the transparent unit 144, towards the central focal point A of the central lens region 1622. This arrangement allows to form a concentrated parallel beam that exits from the center of the light-exit lens surface 164, resulting in a powerful center-concentrated light distribution.

[0048] As illustrated in Figure 5, the light 200 emitted from the two side light source regions 1201 and 1203 is reflected and focused by the total internal reflecting unit 142 towards their respective side lens regions. This arrangement results in a broader light distribution.

[0049] To achieve a homogeneous light distribution with a shorter total length of the light-emitting module 100, the transparent unit 144 of the light reflecting device 140 is more than 6 mm long in the direction of the optical axis of the lens 160. Advantageously, the length of the transparent unit ranges between 6 and 30 mm, preferably between 6 and 15 mm, and optimally measures 8,5 mm. In the present embodiment, the transparent unit 144 is 8.5 mm long.

[0050] The fact that light 200 propagates through a transparent unit 144 that has a length of more than 6 mm allows for more efficient homogenization of the light 200 compared to light propagating through air. As a result, the light exiting from the light-exit surface 146 of the transparent unit 144 is well homogenized, making further propagation through air unnecessary.

[0051] Therefore, in the present embodiment, the light-exit surface 146 of the transparent unit 144 can be positioned in close proximity to the central focal point A of the lens, in this example at a minimum distance of 1.5 mm from the central focal point A.

[0052] The length of the total reflecting unit 142 is selected around 8 mm as in the present embodiment. Preferably, the lengths of the total reflecting unit 142 and / or the transparent unit 144 can vary within the aforementioned range according to manufacturing procedures and / or custom requirements.

[0053] Therefore, the design of the light-emitting module 100 according to the invention can result in a total length of 55 mm, which is significantly shorter than conventional light modules.

[0054] Preferably, especially for the low beam light designs, a shutter 150 is positioned on a bottom surface 145 of the transparent unit 144 of the light-reflecting device 140, as illustrated in Figures 2 and 3.

[0055] Advantageously, the shutter 150 and the transparent unit 144 are integrated into a single piece. Preferably, the light-reflecting device 140 and the shutter 150 are manufactured as a single piece. For instance, both the light-reflecting device and the shutter can be made from transparent polycarbonate (PC).

[0056] Preferably, the lens holder 170 and the light-reflecting device 140 are also made in one-piece.

[0057] Advantageously, the selection of the light sources 121 helps achieving a homogenous concentrated beam in the center and a diffused beam on both sides in the final light distribution. Each light source 121 contains at least a one-chip LED 1211, as illustrated in Figure 6. If a central focal length of the central lens region 1622 is less than 35 mm, the light source 121 of the central light source region 1202 preferably comprises a one-chip LED 1211. If the central focal length of the central lens region 1622 is more than 30 mm, the light source 121 of the central light source region 1202 preferably comprises at least one two-chip LED 1212. A two-chip LED has double the luminance per watt compared to a one-chip LED. In the present embodiment, the light source of the central light source region 1202 consists of a two-chip LED 1212, while each light source 121 of the two side light source regions consists of a one-chip LED 1211, as illustrated in Figure 6.

[0058] The invention is not limited to the presented embodiments and other embodiments will clearly appear to the skilled person. Any combination of the aforementioned embodiments or variants is for example explicitly envisioned.Reference list

[0059] 100: light-emitting module 120: light source unit 1201, 1202, 1203: light source region 121: light source 1211, 1212: LED 140: light reflecting device 142: total internal reflecting unit 1421: total internal reflector 144: transparent unit 145: bottom surface 146: light-exit surface 150: shutter 160: lens 162: light-entry lens surface 1621, 1622, 1623: lens region 164: light-exit lens surface 170: lens holder 172: separating wall 200: light

Examples

Embodiment Construction

[0031]Figures 1 to 3 illustrate a light-emitting module 100 for a vehicle (not shown) comprising a light source unit 120, a light-reflecting device 140 and a lens 160. In this example, the light-emitting module 100 is designed for low beam headlights, with the final light distribution conforming to low beam regulation. However, in other embodiments (not shown), the light-emitting module 100 could be designed to conform to the regulation of other types of beams, such as front fog lamps, high beam headlights, and combined high and low beam headlights.

[0032]The light source unit 120 comprises at least one light source 121, emitting a light 200, as depicted in Figures 4 and 5.

[0033]As illustrated in Figures 1 to 3, the light-reflecting device 140 comprises a total internal reflecting unit 142 and a transparent unit 144 which is directly connected to the total internal reflecting unit 142 in the direction of the optical axis D of the lens 160. The term "transparent" means that it is at l...

FIELD OF THE INVENTION

[0001] The present invention relates to the technical field of light-emitting modules for use in vehicles.BACKGROUND OF THE INVENTION

[0002] Various light-emitting modules for vehicles are known in the prior art to produce an illuminating beam, a signaling beam, or a combination of both.

[0003] In the conventional design of light-emitting modules, to produce at least an illuminating beam, a light source emits a light, and a light-reflecting device (comprising a total internal reflecting unit) is configured to reflect all the light emitted by the light source into parallel and / or convergent beams, towards a lens. The illuminating beam exiting the lens forms a light distribution pattern. The light distribution pattern is typically measured on a surface located 25 m from the light source in a standard test of the light-emitting module in the field of vehicle testing. It is illustrated as an iso-lux diagram, the contours of which represent the points of equal illuminance in lux. The standard test and the iso-lux diagram are known to a person skilled in the art.

[0004] The light distribution pattern must conform to certain regulations for vehicle illuminating beams, such as UN Regulation No. 149 - Road Illumination Devices (RID). According to the requirements of the regulation, firstly, the light distribution should achieve a specified luminance. Secondly, it should conform to certain dimensional requirements, such as width. Thirdly, it should be homogeneous. A homogeneous light distribution is defined as an iso-lux diagram the contours of which have a more or less regular distribution density. Further details are not provided here. Similarly, in the following description, the terms "homogeneous light" and "homogenize the light" are to be understood in the same way as a homogenous light distribution.

[0005] In practice, the light exiting the total internal reflecting unit of the light-reflecting device is far from being homogeneous. To solve this problem, the existing modules has the light propagate through an empty space, i.e., in the air, between the light-reflecting device and the main focal point of the lens. Typically, a minimum distance of about 30 to 50 mm is required for the light to propagate in the air before reaching the main focal point of the lens to ensure a homogenous light distribution according to the regulation. This distance also helps achieve the width of the light distribution required by the regulation. Consequently, the shortest distance from a light-exit surface of the light-reflecting device to the main lens focal point typically ranges between 30 and 50 mm, and the shortest distance from the light source to a main lens focal point typically ranges between 40 and 60 mm. Additionally, the back focal length of the lens ranges typically from 30 to 50 mm, for example, 40 mm. The back focal length is defined as the distance between the focal point of the lens and the center of the surface where the light emitted by the light source enters the lens. This surface is also called a light-entry lens surface.

[0006] If these distances are shorter than the specified ranges, the light distribution may result in an inadequate luminance, non-conforming dimensions or lack of homogeneity, leading to suboptimal illumination performance. Consequently, for front fog lamps, low beam headlights, high beam headlights, and combined high and low beam headlights, the conventional design typically results in a total length of the light-emitting module exceeding 100 mm.

[0007] In addition, for a low beam or a front fog lamp, a cut-off line in the light distribution is required by the regulation. In conventional designs, this necessitates a shutter, separate from other components of the light-emitting module, to be positioned between the light-exit surface of the light-reflecting device and the main focal point of the lens. This placement of the shutter creates the required cut-off line in the light distribution. Therefore, the manufacturing process becomes more complicated due to the involvement of an additional component.

[0008] In recent years, with the developing trend of vehicle styling, especially with the booming development of electric vehicles, more requirements have been placed on the shape and size of the light-emitting modules, which are an important element of front-end and rear-end styling. For instance, for electric vehicles without a front grille, it is advantageous from a styling perspective to arrange the light-emitting modules at the front of the vehicle in the most compact manner possible, particularly in the vehicle's longitudinal direction, i.e., the X-direction. Similarly, a compact design in the longitudinal direction is also highly required for the motorcycles.

[0009] In order to shorten the overall length of the light-emitting module in the X-direction, some existing designs position at least two lenses in a row along the optical axis of the lens (typically parallel to the X-direction). This arrangement shortens the focal length of the set of lenses while still meeting the requirements of the regulation for light distribution. However, this solution significantly increases the manufacturing costs and reduces the optical efficiency of the light-emitting module.

[0010] In other words, the prior art light-emitting modules struggle to meet the new dimensional requirements in the X-direction of the vehicle while satisfying the functional requirements and without increasing the manufacturing costs. Therefore, further improvements to the existing light-emitting modules are necessary.SUMMARY OF THE INVENTION

[0011] The present invention aims to overcome the shortcomings of the prior art by providing a light-emitting module for a vehicle with smaller total length, whilst maintaining the light distribution according to the requirements of the regulation and not increasing manufacturing costs. It is important to note that in the present description, the term "length" always refers to the length along the optical axis of the lens of the light-emitting module, which in most cases coincides with the X-direction of the vehicle as previously defined.

[0012] The light-emitting module in the present invention can be used in various types of vehicle lamps, including but not limited to, front fog lamps, low beam headlights, high beam headlights, and combined high and low beam headlights.

[0013] To this end, the invention relates to a light-emitting module for a vehicle, comprising: a light source unit emitting light, a light-reflecting device comprising a first part and a second part, wherein the first part is a total internal reflecting unit configured to reflect all the light emitted by the light source unit into parallel and / or convergent beams, and the second part is a transparent unit directly connected to the total internal reflecting unit and having a light-exit surface, a lens having an optical axis, comprising a light-entry lens surface and a light-exit lens surface, wherein the transparent unit of the light-reflecting device has a minimum length of 6 mm along the direction of the optical axis of the lens, the light-entry lens surface comprises at least two lens regions along a direction perpendicular to the optical axis of the lens, with the at least two lens regions having different focal points, the light source unit comprises at least two light source regions in the direction perpendicular to the optical axis of the lens, each light source region comprising at least one light source, with light emitted from each light source region being directed towards each lens region respectively.

[0014] Firstly, thanks to the transparent unit having a length of at least 6 mm, it homogenizes the light more efficiently than air. This ensures that the light is sufficiently homogenized, as required by the regulation, over a shorter distance within the transparent unit, instead of through the air like in the prior art. Consequently, the light-exit surface of the transparent unit can be positioned in close proximity to a main focal point of the lens, for example, at a distance from the main focal point ranging between 0 and 2 mm.

[0015] Secondly, the design features at least two lens regions, each with its own focal point corresponding to a respective light source region. This arrangement maintains the required width of the light distribution, according to the regulation, while allowing the light sources to be placed closer to the lens than in the prior art. Additionally, the combination of the above two features has a synergistic effect, allowing to significantly reduce the total length of the light-emitting module to, for example, approximately 55 mm, compared to over 100 mm in the prior art.

[0016] According to preferred embodiments, the light-emitting module for a vehicle according to the invention may further comprise the following features, implemented separately or in each of their technically operative combinations.

[0017] Advantageously, the light-emitting module comprises a lens holder extending along the direction of the optical axis of the lens, with the lens being fixed to the lens holder. The lens holder supports the lens and blocks the stray light.

[0018] According to a preferred embodiment, the lens holder and the light-reflecting device are made in one-piece.

[0019] Preferably, the lens holder comprises at least one separating wall extending along the direction of the optical axis of the lens separating the at least two lens regions. The number of separating walls equals to the number of lens regions minus one.

[0020] The separating wall is used to channel light emitted from at least two light source regions into their respective lens regions without contamination from neighboring region(s). It also serves to block stray light reflected by the total internal reflecting unit, resulting in a more refined final light distribution.

[0021] Advantageously, the separating wall(s) and / or said lens holder comprising said separating wall(s) are made of a light-absorbing material, such as black polycarbonate (PC).

[0022] According to a preferred embodiment, the light-emitting module comprises a shutter integrated on a bottom surface of the transparent unit of the light-reflecting device. The bottom surface refers to the surface facing downward once the light-emitting module is installed on a vehicle. The shutter is for creating a cut-off line at the upper edge of the final light distribution to comply with the regulation.

[0023] For comparison, in conventional light-emitting modules, a separate shutter, typically made of metal, is positioned between the lens focal points and the light-reflecting device along the direction of the optical axis of the lens. In the present invention, integrating the shutter into the light-reflecting device reduces the number of optical components in the light-emitting module, lowers its weight, enhances compactness, and reduces manufacturing complexity and costs.

[0024] Advantageously, the shutter and the transparent unit are made in one piece. Preferably, the light-reflecting device is also made in one piece. The number of mounting parts and assembly steps is therefore reduced, simplifying the assembly of the light-emitting module and lowering manufacturing costs.

[0025] Advantageously, each light source region comprises at least one light source, each light source comprises at least one light-emitting diode (LED). The total internal reflecting unit comprises at least two total internal reflectors, each connected to a respective light source, configured to reflect all the light emitted by the light source into parallel and / or convergent beams.

[0026] According to a preferred embodiment, the light-entry lens surface comprises three lens regions, and the light source units comprises three light source regions. Advantageously, the three lens regions are composed of one central lens region having a main focal point, and two side lens region each having a side focal point which is aligned with the light source along the direction of the optical axis of the lens. For example, the three lens regions are composed of one central lens region having a back focal length ranging between 20 and 30 mm, preferably 27 mm, and two side lens regions each having a back focal length ranging between 50 to 60mm, preferably 51.5 mm.

[0027] Advantageously, according to the above embodiment, the lens holder comprises two separating walls and separating the three lens regions.

[0028] Preferably, the three light source regions are composed of a center light source region comprising one light source and two side light source regions each comprising two light sources. For example, the central light source region comprises one light source with at least one two-chip LED, while each side light source region comprises two light sources, each with one one-chip LED.

[0029] The invention also relates to a vehicle comprising at least one light-emitting module as described above.BRIEF DESCRIPTION OF THE FIGURES

[0030] The invention will be better understood upon reading the following description, provided only as an illustrative example. The terms "top", "bottom", "front" and "rear" refer to the directions once the light-emitting module is installed on a vehicle. The following description is with reference to the attached drawings in which: Figure 1 is a top view of the light-emitting module according to a particular embodiment of the invention, Figure 2 is a side view of the light-emitting module of Figure 1, Figure 3 is a perspective view of the light-emitting module of Figure 1, Figure 4 is an illustrative view depicting a first part of the optical path of the light-emitting module of Figure 1, Figure 5 is an illustrative view depicting a second part of the optical path of the light-emitting module of Figure 1, Figure 6 is a front view of the light-reflecting device of the light-emitting module of Figure 1, showing a front view of the light source unit through the transparent unit. DETAILED DESCRIPTION

[0031] Figures 1 to 3 illustrate a light-emitting module 100 for a vehicle (not shown) comprising a light source unit 120, a light-reflecting device 140 and a lens 160. In this example, the light-emitting module 100 is designed for low beam headlights, with the final light distribution conforming to low beam regulation. However, in other embodiments (not shown), the light-emitting module 100 could be designed to conform to the regulation of other types of beams, such as front fog lamps, high beam headlights, and combined high and low beam headlights.

[0032] The light source unit 120 comprises at least one light source 121, emitting a light 200, as depicted in Figures 4 and 5.

[0033] As illustrated in Figures 1 to 3, the light-reflecting device 140 comprises a total internal reflecting unit 142 and a transparent unit 144 which is directly connected to the total internal reflecting unit 142 in the direction of the optical axis D of the lens 160. The term "transparent" means that it is at least transparent to any light radiation having a wavelength comprised in the visible spectrum, that is to say, comprised between about 380 and 780 nm. In the present disclosure, "translucent" is not considered "transparent".

[0034] The total internal reflecting unit 142 is in contact with the light source unit 120. Typically, the total internal reflecting unit 142 contains total internal reflectors 1421, with each total internal reflector 1421 corresponding to each light source 121. These total internal reflectors are commonly made of reflective coated mirrors, and the inner surface of the total internal reflector 1421 is shaped as an ellipsoid, paraboloid, hyperboloid or a free-form surface.

[0035] The transparent unit 144 comprises a light-exit surface 146. The light-exit surface 146 may or may not be a continuous curve, designed to orient the light 200 at specific angles to achieve a final light distribution according to the regulations. The method for defining the geometry of the light-exit surface 146 is considered general knowledge to a person skilled in the art, hence, the details will not be provided here.

[0036] The lens 160 comprises a light-exit lens surface 164 and a light-entry lens surface 162.

[0037] In the present embodiment, the light-entry lens surface 162 is divided into three lens regions, 1621, 1622 and 1623, in a direction perpendicular to the optical axis D of the lens 160. The optical axes of these different regions are typically parallel to each other, so only one optical axis D is used to represent the direction of all the optical axes.

[0038] Preferably, the lens regions 1621, 1622 and 1623 can have different or identical dimensions and / or curvatures. As an example, the light-entry lens surface 162 in each lens region 1621, 1622 and 1623can be a single-curved surface or an undulated surface. A flexible design is possible according to custom requirements.

[0039] Dividing the light-entry lens surface 162 into regions allows reducing the thickness (in the direction of the optical axis) of the lens 160, the overall weight of the light-emitting module 100, and, consequently, its manufacturing costs.

[0040] The height and width of each lens region 1621, 1622 and 1623 preferably range between 10 and 30 mm, respectively. In the present embodiment, the total width of the lens 160 is 60 mm, and its height is 15 mm. The width corresponds to the Y direction as indicated in Figure 1, and the height corresponds to the Z direction. As a reference, once the light-emitting module 100 is installed on a vehicle, the X direction represents the longitudinal axis of the vehicle in the use position, Y direction represents the transverse axis of the vehicle, and the Z direction represents the vertical direction of the vehicle. In the embodiment shown in the Figures, the X direction coincides with the direction of the optical axis D of the lens.

[0041] In the present embodiment, each lens region measures 20 mm in width and 15 mm in height.

[0042] Each lens region 1621, 1622 and 1623 can have the same or different back focal lengths. Preferably, for a low beam light-emitting module, at least two regions have different back focal lengths. In the present embodiment, the central lens region 1622 has a back focal length of 27 mm, while each of the two side lens regions 1621 and 1623 have a back focal length of 51.5 mm. In addition, in the present embodiment, the thickness (in the direction of the optical axis) of the lens 160 measured in the center of the central lens region is 10 mm, while the thickness of the lens 160 measured in the center of each side lens region is about 3.5 mm.

[0043] The focal points can be positioned at different depths along the X direction. As illustrated in Figure 1, the central focal point A of the central lens region 1622 is located approximately at the light-exit surface 146 of the transparent unit 144 of the light-reflecting device 140, whereas focal points B and C of the side lens regions 1621 and 1623 are positioned at the level of the light sources 121 of the light source unit 120.

[0044] The selection of the focal lengths for the different lens regions 1621, 1622 and 1623 depends on regulatory requirements and specific custom preferences. The design of the present embodiment enables a center-concentrated beam in the final light distribution and optimizes the width of the overall light distribution.

[0045] Preferably, the light-emitting module 100 includes a lens holder 170 to securely hold the lens 160. The lens holder 170 is elongated along the optical axis of the lens 160. Advantageously, the lens holder 170 comprises side walls which serves to block stray light. In the present embodiment, advantageously, the lens holder 170 is divided into three regions corresponding to the three lens regions 1621, 1622 and 1623 by two separating walls 172. Preferably, the separating wall(s) 172 and / or the lens holder 170 are made of a light-absorbing material, such as black polycarbonate (PC).

[0046] In the present embodiment, the light source unit 120 comprises five light sources distributed across three light source regions, 1201, 1202 and 1203, corresponding to the three lens regions 1621, 1622 and 1623. The central light source region 1202 includes one light source 121, while each of the two side sources regions, 1201 and 1203, includes two light sources 121.

[0047] As illustrated in Figure 4, the light 200 emitted from the central light source region 1202 is reflected and focused by the total internal reflecting unit 142, propagating through the transparent unit 144, towards the central focal point A of the central lens region 1622. This arrangement allows to form a concentrated parallel beam that exits from the center of the light-exit lens surface 164, resulting in a powerful center-concentrated light distribution.

[0048] As illustrated in Figure 5, the light 200 emitted from the two side light source regions 1201 and 1203 is reflected and focused by the total internal reflecting unit 142 towards their respective side lens regions. This arrangement results in a broader light distribution.

[0049] To achieve a homogeneous light distribution with a shorter total length of the light-emitting module 100, the transparent unit 144 of the light reflecting device 140 is more than 6 mm long in the direction of the optical axis of the lens 160. Advantageously, the length of the transparent unit ranges between 6 and 30 mm, preferably between 6 and 15 mm, and optimally measures 8,5 mm. In the present embodiment, the transparent unit 144 is 8.5 mm long.

[0050] The fact that light 200 propagates through a transparent unit 144 that has a length of more than 6 mm allows for more efficient homogenization of the light 200 compared to light propagating through air. As a result, the light exiting from the light-exit surface 146 of the transparent unit 144 is well homogenized, making further propagation through air unnecessary.

[0051] Therefore, in the present embodiment, the light-exit surface 146 of the transparent unit 144 can be positioned in close proximity to the central focal point A of the lens, in this example at a minimum distance of 1.5 mm from the central focal point A.

[0052] The length of the total reflecting unit 142 is selected around 8 mm as in the present embodiment. Preferably, the lengths of the total reflecting unit 142 and / or the transparent unit 144 can vary within the aforementioned range according to manufacturing procedures and / or custom requirements.

[0053] Therefore, the design of the light-emitting module 100 according to the invention can result in a total length of 55 mm, which is significantly shorter than conventional light modules.

[0054] Preferably, especially for the low beam light designs, a shutter 150 is positioned on a bottom surface 145 of the transparent unit 144 of the light-reflecting device 140, as illustrated in Figures 2 and 3.

[0055] Advantageously, the shutter 150 and the transparent unit 144 are integrated into a single piece. Preferably, the light-reflecting device 140 and the shutter 150 are manufactured as a single piece. For instance, both the light-reflecting device and the shutter can be made from transparent polycarbonate (PC).

[0056] Preferably, the lens holder 170 and the light-reflecting device 140 are also made in one-piece.

[0057] Advantageously, the selection of the light sources 121 helps achieving a homogenous concentrated beam in the center and a diffused beam on both sides in the final light distribution. Each light source 121 contains at least a one-chip LED 1211, as illustrated in Figure 6. If a central focal length of the central lens region 1622 is less than 35 mm, the light source 121 of the central light source region 1202 preferably comprises a one-chip LED 1211. If the central focal length of the central lens region 1622 is more than 30 mm, the light source 121 of the central light source region 1202 preferably comprises at least one two-chip LED 1212. A two-chip LED has double the luminance per watt compared to a one-chip LED. In the present embodiment, the light source of the central light source region 1202 consists of a two-chip LED 1212, while each light source 121 of the two side light source regions consists of a one-chip LED 1211, as illustrated in Figure 6.

[0058] The invention is not limited to the presented embodiments and other embodiments will clearly appear to the skilled person. Any combination of the aforementioned embodiments or variants is for example explicitly envisioned.Reference list

[0059] 100: light-emitting module 120: light source unit 1201, 1202, 1203: light source region 121: light source 1211, 1212: LED 140: light reflecting device 142: total internal reflecting unit 1421: total internal reflector 144: transparent unit 145: bottom surface 146: light-exit surface 150: shutter 160: lens 162: light-entry lens surface 1621, 1622, 1623: lens region 164: light-exit lens surface 170: lens holder 172: separating wall 200: light

Examples

Embodiment Construction

[0031]Figures 1 to 3 illustrate a light-emitting module 100 for a vehicle (not shown) comprising a light source unit 120, a light-reflecting device 140 and a lens 160. In this example, the light-emitting module 100 is designed for low beam headlights, with the final light distribution conforming to low beam regulation. However, in other embodiments (not shown), the light-emitting module 100 could be designed to conform to the regulation of other types of beams, such as front fog lamps, high beam headlights, and combined high and low beam headlights.

[0032]The light source unit 120 comprises at least one light source 121, emitting a light 200, as depicted in Figures 4 and 5.

[0033]As illustrated in Figures 1 to 3, the light-reflecting device 140 comprises a total internal reflecting unit 142 and a transparent unit 144 which is directly connected to the total internal reflecting unit 142 in the direction of the optical axis D of the lens 160. The term "transparent" means that it is at l...

Claims

1. A light-emitting module (100) for a vehicle, comprising: - a light source unit (120), emitting light (200), - a light-reflecting device (140), comprising a first part and a second part, wherein the first part is a total internal reflecting unit (142) configured to reflect all the light (200) emitted by the light source unit (120) into parallel and / or convergent beams, and the second part is a transparent unit (144) directly connected to the total internal reflecting unit (142) and having a light-exit surface (146), and a lens (160) having an optical axis (D), comprising a light-entry lens surface (162) and a light-exit lens surface (164), characterized in that - the transparent unit (144) of the light-reflecting device (140) has a minimum length of 6 mm along the direction of the optical axis (D) of the lens (160), - the light-entry lens surface (162) comprises at least two lens regions (1621, 1622, 1623) along a direction perpendicular to the optical axis (D) of the lens (160), with the at least two lens regions (1621, 1622, 1623) having different focal points, - the light source unit (120) comprises at least two light source regions (1201, 1202, 1203) in the direction perpendicular to the optical axis (D) of the lens (160), each light source region (1201, 1202, 1203) comprising at least one light source (121), with light emitted from each light source region (1201, 1202, 1203) being directed towards each lens region (1201, 1202, 1203), respectively.

2. The light-emitting module (100) for a vehicle according to claim 1, comprising a lens holder (170) extending along the direction of the optical axis (D) of the lens (160), with the lens (160) being fixed to the lens holder (170).

3. The light-emitting module (100) for a vehicle according to claim 2, wherein the light-reflecting device (140) and the lens holder (170) are made in one piece.

4. The light-emitting module (100) for a vehicle according to any of claims 2 to 3, wherein the lens holder (170) comprises at least one separating wall (172) extending along the direction of the optical axis (D) of the lens and separating the at least two lens regions.

5. The light-emitting module (100) for a vehicle according to claim 4, wherein the separating wall(s) (172) and / or the lens holder (170) comprising said separating wall(s) are made of a light-absorbing material, such as black polycarbonate.

6. The light-emitting module (100) for a vehicle according to any one of the preceding claims, wherein a shutter (150) is integrated to a bottom surface (145) of the transparent unit (144) of the light-reflecting device (140).

7. The light-emitting module (100) for a vehicle according to claim 6, wherein the shutter (150) and the transparent unit (144) are made in one piece.

8. The light-emitting module (100) for a vehicle according to any one of the preceding claims, wherein the light-reflecting device (140) is made in one piece.

9. The light-emitting module (100) for a vehicle according to any one of the preceding claims, wherein each light source region (1201, 1202, 1203) comprises at least one light source (121), each light source (121) comprising at least one light-emitting diode (1211,1212).

10. The light-emitting module (100) for a vehicle according to any one of the preceding claims, wherein the light-entry lens surface (162) comprises three lens regions (1621, 1622, 1623), and the light source unit (120) comprises three light source regions (1201, 1202, 1203).

11. The light-emitting module (100) for a vehicle according to claims 4 and 10 taken in combination, wherein the lens holder (170) comprises two separating walls (172) and separating the three lens regions.

12. The light-emitting module (100) for a vehicle according to any of claims 10 to 11, wherein the light-entry lens surface (162) comprises a center lens region (1622) having a back focal length ranging between 20 and 30 mm, and two side lens regions (1621, 1623) each having a back focal length ranging between 50 and 60 mm.

13. The light-emitting module (100) for a vehicle according to any of claims 10 to 12, wherein the three light source regions (1201, 1202, 1203) are composed of a center light source region (1202) comprising one light source (121) and two side light source regions (1201, 1203) each comprising two light sources (121).

14. The light-emitting module (100) for a vehicle according to claim 13, wherein the one light source (121) of the central light source region (1202) contains at least one two-chip light-emitting diode (1212) and each of the two light sources (121) of each side light source region (1201, 1203) contains one one-chip light-emitting diode (1211).

15. A vehicle, characterized in that it comprises at least one light-emitting module (100) according to any one of claims 1 to 14.

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