Lighting module and associated occupant monitoring device

Abstract

The present invention relates to an illumination module comprising at least one light source (220) designed to emit a beam (222) consisting of a set of light rays (228), each light source having a periphery and a reflector (223) having at least one reflective surface (224R, 225R) arranged to at least partially reflect the beam (222). According to the invention, the reflector is configured to extend only over a portion of the periphery of the light source to provide free space, and the at least one reflective surface is arranged such that, after reflection from the reflective surface, at least a portion of the light rays (228) of the beam is reflected beyond the beam emitted by the at least one light source, and this portion of the light rays then passes through the free space disposed around the at least one light source.

Description

Technical Field

[0001] This invention relates generally to a lighting module.

[0002] More specifically, the present invention relates to an illumination module comprising at least one light source capable of emitting a light beam, and a reflector capable of reflecting the light beam to illuminate a region of interest.

[0003] The present invention also relates to a device for monitoring occupants of a motor vehicle, including such a lighting module. Background Technology

[0004] To improve the safety of motor vehicle occupants, a known practice is to equip vehicles with devices for monitoring occupants (more specifically, the driver). Driver behavior can be monitored using sensors specifically placed at the front of the vehicle's passenger compartment. Signs of driver inattention, such as drowsiness or intoxication, can trigger an alarm if necessary.

[0005] For example, an imaging system can be used to monitor occupant behavior. This imaging system typically includes an illumination module designed to illuminate areas of interest, such as the occupant's face and torso, or more generally, the front of the vehicle's passenger compartment.

[0006] The illumination module is accompanied by an image acquisition module, specifically a camera, to capture images of the region of interest illuminated by the illumination module. Finally, the system is typically completed by an image processing module, which can analyze the acquired images and infer any signs of a lack of alertness on the part of the occupant or driver.

[0007] Typical lighting modules usually include a set of light sources, such as light-emitting diodes, each emitting multiple rays that form a beam. This beam can be associated with an emission angle, the value of which can be evaluated as the half-width at the half-maximum of the angular distribution of the light source's intensity.

[0008] Typically, most light-emitting diodes have an emission angle close to 60° (here and throughout the rest of the specification, the symbol ° indicates an angle in degrees). This results in an emission field of 120°.

[0009] Each light source is then surrounded by a reflector (also called a collector). This allows the luminous flux emitted toward the region of interest to be concentrated by means of a reflective surface oriented toward the light source.

[0010] The combination of a light source and a reflector defines an illumination field that angularly delineates an illuminated area corresponding to the region of interest. Preferably, this illuminated area has a rectangular shape, suitable for the elongated structure of the vehicle's passenger compartment as seen from the front.

[0011] However, due to the small space typically located in the passenger compartment of a vehicle, the distance between occupant monitoring equipment and the area of ​​interest is limited to tens of centimeters, usually on the order of 60 to 100 centimeters.

[0012] In order to have a sufficiently large lighting area, a lighting field with a sufficiently wide angle is required, such as equal to or even greater than 180°.

[0013] However, the edges of the reflector surrounding the light source obstruct the emitted beam and limit the illumination field in terms of angle.

[0014] Therefore, the known illumination field is limited to a maximum range of approximately 160°, which is lower than the 180° expected in the context of the target application. Summary of the Invention

[0015] In this context, an illumination module incorporating a reflector is proposed, which is capable of extending the illumination field relative to the emission field of a single light source.

[0016] More specifically, according to the invention, an illumination module is proposed comprising at least one light source designed to emit a light beam, for example in the form of an emission cone, the light beam consisting of a set of rays, each light source having a periphery and a reflector having at least one reflective surface arranged to at least partially reflect the light beam, wherein the reflector is provided to be configured to extend only on a portion of the periphery of the at least one light source to form a free space, and the at least one reflective surface is arranged such that after reflection on the reflective surface, for example after specular reflection or diffuse reflection, at least a portion of the light beam is reflected outside the light beam emitted by the at least one light source, the light reflected outside the light beam partially passing through the free space formed on the periphery of the light source.

[0017] In other words, the reflector has a shape such that it does not surround at least one light source, and it reflects a portion of the light emitted by the light source in a direction away from the direction of the beam originally emitted by the light source.

[0018] With the help of this invention, a large and near region of interest can be illuminated due to the sufficiently wide illumination field. This is because the reflector is therefore configured to block the light beam emitted by the light source as little as possible, and the reflective surface of the reflector is shaped to deflect the light beam at an angle in order to have the widest possible illumination field.

[0019] Other advantageous and non-limiting (i.e., optional) features of the lighting module according to the invention, taken individually or in any technically possible combination, are as follows:

[0020] - The at least one reflective surface is at least partially non-planar.

[0021] - The at least one reflective surface is convex relative to the at least one light source, and the at least one reflective surface is arranged relative to the at least one light source to at least partially reflect the light beam.

[0022] - The at least one light source emits light in a direction referred to as the illumination direction, and the portion of the light reflected outside the beam forms an angle greater than or equal to 90° with the illumination direction.

[0023] The lighting module includes multiple light sources, and / or the reflector includes multiple reflective surfaces. The lighting module can then have a central region where the multiple reflective surfaces of the reflector are positioned. The central region can also be surrounded by a peripheral region where multiple light sources are positioned, such that the reflector is surrounded by multiple light sources. Therefore, the number of components within the lighting module is advantageously reduced, as one reflector can be used for multiple light sources. In addition to reducing the weight and / or cost of the components, this also simplifies module assembly.

[0024] - Each of the reflective surfaces of the reflector is oriented toward at least one of the light sources. For example, the reflective surfaces of the reflector may be oriented toward one, two, or more light surfaces. The number of sources to be used can be selected, for example, according to the lighting requirements.

[0025] The lighting module includes a printed circuit board, and the plurality of light sources are fastened to the printed circuit board. In this case, the module includes a single printed circuit board, rather than multiple, which is possible when the emission axes of the different sources are collinear rather than tilted, in order to maximize the illumination field.

[0026] - The reflector is formed as a single piece. In other words, the reflective surface can be continuous, or optionally connected by reflective or non-reflective surfaces.

[0027] - The at least one light source includes at least one light-emitting diode.

[0028] The present invention also proposes an occupant monitoring device for a motor vehicle, comprising an acquisition module capable of imaging a region of interest at least partially illuminated by an illumination module according to the invention. The monitoring device may optionally have the following optional features, which may be employed individually or in any technically possible combination:

[0029] - The acquisition module is placed in the central area of ​​the lighting module.

[0030] The acquisition module is at least partially surrounded by reflectors, particularly by the sidewalls that form it, and multiple light sources are arranged around the acquisition module to surround it. Therefore, this configuration saves space and makes the occupant monitoring equipment more compact.

[0031] - The motor vehicle includes a passenger compartment, and the area of ​​interest of the occupant monitoring equipment includes at least part of the front space of the passenger compartment of the motor vehicle.

[0032] Of course, different features, variations and embodiments of the present invention can be associated with each other in various combinations, as long as they are not incompatible or mutually exclusive. Attached Figure Description

[0033] The following description, given with reference to the accompanying drawings provided by way of non-limiting example, will allow a clear understanding of what the invention includes and how it can be practiced.

[0034] In the attached diagram:

[0035] Figure 1 This is a schematic diagram of a motor vehicle equipped with an occupant monitoring device including a lighting module according to the present invention;

[0036] Figure 2 It is included in, for example Figure 1 A schematic diagram of the lighting module in the occupant monitoring equipment, specifically showing the light beam emitted by the light source of the lighting module;

[0037] Figure 3 yes Figure 2 A schematic front view of the lighting module, specifically showing the reflector surrounded by two light sources; and

[0038] Figure 4 yes Figure 2 A schematic side view of the lighting module. Detailed Implementation

[0039] Figure 1 The motor vehicle 1 shown here is in the form of an automobile, but it can be a completely different type of motor vehicle 1 (truck, ship, airplane, etc.).

[0040] The motor vehicle 1 includes a passenger compartment in which occupants 4 reside. These occupants 4 can refer to several groups of people, such as a single driver; a driver and a front passenger; a driver, a front passenger, and a rear passenger, etc.

[0041] The motor vehicle 1 is equipped with a device 2 for monitoring occupants 4. The function of this device is to ensure that occupants 4 of the motor vehicle 1 do not engage in dangerous behavior. The example disclosed herein relates to a device 2 for monitoring the driver and front-seat passenger.

[0042] In this example, the region of interest 3 of the monitoring device 2 thus represents an area extending along the width of the motor vehicle 1, which is preferably rectangular and represented by the axis GD, extending from the driver to the front passenger.

[0043] When the driver and front passenger adopt a normal driving posture, Figure 1 The area of ​​interest 3, schematically shown in the diagram, includes in particular the face and part of the torso of the driver and front passenger, as well as the driver's arm.

[0044] Typically, the monitoring device 2 is placed in the front of the passenger compartment of the motor vehicle 1, for example, in the area adjacent to the upper or lower part of the windshield of the motor vehicle 1, on the dashboard of the motor vehicle 1, or in the rearview mirror.

[0045] Here, monitoring device 2 relies on visual information obtained through image recording and analysis.

[0046] Therefore, the monitoring device 2 includes a lighting module 22, an acquisition module 20 capable of acquiring images thereon, and a computer 24.

[0047] according to Figure 1 In the depiction described above, the three aforementioned components are considered to be housed within the same dedicated housing. According to a possible variation, the computer 24 is located at a distance from the lighting module 22 and the image acquisition module 20, in which case it will be able to exchange data with these two other modules, for example, via an in-vehicle network.

[0048] The acquisition module 20 acquires images of the region of interest 3 at given time intervals, and then the computer 24 analyzes these images to trigger an alarm if necessary.

[0049] The acquisition module 20 includes a photosensitive sensor and an imaging optics device, which is capable of imaging the region of interest 3 onto the photosensitive sensor located downstream of the imaging optics device.

[0050] Imaging optics can specifically refer to lenses, as well as optical bandpass filters designed to eliminate any stray radiation emitted outside the spectral range of interest.

[0051] The photosensitive sensor groups together a set of photosensitive pixels arranged in an array. These pixels are photosensitive to a spectral range that at least partially covers the spectral range of the illumination module 22. Here, it can be, in particular, the visible light range, or the infrared range (especially the near-infrared range). These spectral ranges will be defined in more detail in the remainder of this specification.

[0052] To actively illuminate region of interest 3, illumination module 22 is used to illuminate at least a portion of the illumination area corresponding to region of interest 3. Here, these two areas are... Figure 1 and Figure 2 They are depicted as overlapping.

[0053] In applications such as "surveillance equipment," the spectral range chosen for illumination is typically in the infrared range, particularly the near-infrared range. This is because this spectral range is invisible to the human eye and thus avoids dazzling the occupants. However, illumination spectral ranges within the visible light range are also possible.

[0054] In this example, the illumination module 22 therefore emits radiation in the spectral range between 700 nm and 2000 nm, or even in the spectral range extending into the visible light range, thus ranging from 400 nm to 2000 nm. This radiation can be monochromatic or polychromatic.

[0055] Specifically, in the disclosed embodiments, the irradiation wavelength is 940 nm.

[0056] Then, in order to illuminate the entire region of interest 3, the lighting module 22 preferably includes multiple light sources 220. In particular, in the illustrated embodiment, the lighting module 22 includes two light sources 220.

[0057] Depending on possible variations, the lighting module 22 may also include one, four, six, or eight light sources 220.

[0058] These light sources 220 can refer to, for example, any type of light-emitting diode (often also called an LED), or a vertical-cavity surface-emitting laser (VCSEL) diode, or any other light source capable of emitting radiation within a spectral range selected for illumination.

[0059] Here, in the embodiment discussed, the described lighting module 22 includes two LEDs. Furthermore, it is assumed that these two light sources 220 are identical. However, it is conceivable to use light sources 220 with different characteristics according to a variation of the invention.

[0060] These two LEDs can emit light radiation with a wavelength of about 940 nm, and their spectral width is tens of nanometers.

[0061] As described above, in the context of monitoring device 2, the area of ​​interest 3 ideally takes the form of a rectangle extending along axis GD. Therefore, it is desirable to obtain illumination of an area with a similar shape in order to illuminate the driver and front passenger.

[0062] In this embodiment, the two light sources 220 of the lighting module 22 are therefore considered to be positioned horizontally along the axis GD.

[0063] The two light sources 220 considered here can be separated by a few millimeters to tens of millimeters. For example, here, the distance between the two light sources 220 is 13mm.

[0064] Depending on the lighting requirements or the characteristics of the light source 220 used, other arrangements of the light source 220 are possible.

[0065] Each light source 220 of the illumination module 22 emits a set of light rays 228 that form a beam 222. The beam 222 is three-dimensional and has a spatial distribution that may be non-uniform and without rotational symmetry.

[0066] For the sake of simplicity in the remainder of the specification, and as shown in all the figures, the beam 222 emitted by each light source 220 is described as a rotationally symmetric emission cone, corresponding to a reasonable model of the described situation. This emission cone is depicted by its vertices and the apex angles relative to the axes defined as emission axes A1, A2.

[0067] Preferably, the two emission axes A1 and A2 of the two light sources 220 are collinear, such that the two light sources 220 illuminate in a common direction, which is called the illumination direction. Here, the illumination direction is parallel to the emission axes A1 and A2 and oriented towards the region of interest 3. Therefore, the two emission axes A1 and A2 are parallel to the axis AA' that describes the front and rear axes of the motor vehicle 1.

[0068] However, other embodiments are also conceivable, where the emission axes A1 and A2 of different sources are not collinear, and the sources can be tilted relative to axis AA'. The illumination direction will then remain parallel to axis AA' and oriented towards the region of interest 3.

[0069] However, collinearity of the emission axes A1 and A2 has the following advantages: different light sources 220 can be fixed on the same printed circuit board 221. In one possible exemplary embodiment, a single printed circuit board 221 serves as a support for all the light sources 220 of the lighting module 22, and also as a control for the different light sources 220 fixed thereon.

[0070] Due to the spatial arrangement of region of interest 3 relative to the passenger compartment of vehicle 1, again for simplicity, the remainder of this specification will only consider angles measured in a plane containing axis GD and axis AA'.

[0071] For beam 222, the vertex of the emission cone is located at the light source 220, assumed to be a point, and the vertex angle in the plane containing axis GD and axis AA corresponds to the emission angle of the light source 220. The launch angle It can be defined, for example, as the half-width (FWHM) at the half-maximum of the angular distribution of the intensity of light source 220. Emission angle The value is measured as an absolute value relative to the emission axes A1 and A2. Other possible definitions of the emission angle of the light source can be used.

[0072] exist Figure 2 , Figure 3 and Figure 4 The image shows this beam 222 in the emission cone. Specifically, Figure 2 and Figure 4 The above-mentioned launch angle is shown. .

[0073] emission angle of light source 220° The angle is between 0° and 90°, and varies depending on the light source 220 under discussion. Typically, the emission angle... Less than 80°.

[0074] In the discussed embodiment, the two beams 222 in the two separate emission cones are each emitted from the light source 220.

[0075] All light sources 220 of the lighting module define an emission field along the vehicle's axis GD, i.e., in a plane containing axis GD and axis AA', by the emission angle corresponding to the light source 220. The angle is twice that of light source 220, which is the same here.

[0076] The emission field of light source 220 is between 0° and 180°, less than 180°. For example, in the described embodiment, the emission field of light source 220 is equal to 160°.

[0077] In addition, in order to prevent the edge of the printed circuit board 221 from limiting the emission field, the light source 220 of the illumination module 22 is placed at the end of one edge of the printed circuit board 221 by partially blocking the beam 222.

[0078] Here, the different light sources 220 are therefore each placed a few micrometers away from one edge of the printed circuit board 221, for example, between 100 and 500 μm from the edge.

[0079] To guide the light beam 222 emitted by the light source 220 to optimally illuminate the region of interest 3, the illumination module 22 also includes a reflector 223. The reflector 223 performs several functions, including shaping the illumination area to optimally correspond to the geometry of the region of interest 3, and, for example, appropriately distributing luminous flux over the area.

[0080] After reflection at reflector 223, the light beam 222 defines an angularly defined illumination field. This illumination field differs from the emission field defined solely by the light source 220. This reflection corresponds, for example, to specular reflection or diffuse reflection, depending on the reflector 223 in question.

[0081] Illumination field Figure 1 and Figure 2As shown, and specifically located below region of interest 3. It is angularly defined by twice the angle corresponding to the illumination angle. This angle is also measured relative to axis AA' in a plane containing axis GD and axis AA', or, if the three axes are collinear, in a manner equivalent to the emission axes A1 and A2 of the light source 220.

[0082] exist Figure 3 The reflector 223 is shown in more detail in the front view.

[0083] It has multiple sidewalls 224, 225, 226, 227, four in this case, defining the volume of the parallelepiped shape. These sidewalls 224, 225, 226, 227 extend substantially at a height along the axis AA', such that they can reflect the light 228 emitted by the light source 220.

[0084] The four sidewalls 224, 225, 226, and 227 of the reflector 223 are adjacent along the axis AA', such that the four sidewalls 224, 225, 226, and 227 connected in this way form a boundary with openings at both ends along the axis AA'.

[0085] The first end contacts, or even penetrates, the printed circuit board 221 to a depth ranging from 1 mm to 10 mm, to secure the reflector 223 to the lighting module 22. Alternatively, the reflector 223 and the printed circuit board 221 are held by a housing. This housing is specifically configured such that it does not obstruct the passage of light 228 reflected from the reflector 223. For example, the light source 220 may be positioned a few micrometers from one edge of the housing. The housing then has thin walls and / or the walls of the housing are at least partially transparent to the spectral range of the illumination.

[0086] Depending on the variant, other solutions for retaining the reflector 223 on the printed circuit board 221 and / or housing are possible, such as by providing fastening tabs that extend beyond one of the ends of the reflector 223. These tabs can then be screwed, soldered, or glued to the printed circuit board 221 and / or housing.

[0087] The second end of the reflector 223, which is opposite to the end of the contact printed circuit board 221, remains open.

[0088] In the described embodiment, the reflector 223 is therefore integrally formed.

[0089] According to other possible embodiments, discontinuous sidewalls 224, 225, 226, 227 are also conceivable, and the reflector 223 would then be made using several separate components.

[0090] In the described embodiment, the reflector 223 is sized within a parallelepiped 10 mm wide and 3 mm high, with the height described along axis AA'.

[0091] Here, a single reflector 223 is used to reflect all the beams 222 generated by the multiple light sources 220 of the illumination module 22.

[0092] The lighting module 22 comprises two distinct regions, wherein the central region of the integral reflector 223 is surrounded by a peripheral region in which a light source 220 is positioned. In other words, a single reflector 223 of the lighting module 22 is placed in the center and surrounded by different light sources 220.

[0093] Various geometric arrangements of the light source 220 can be considered. For example, here, two light sources 220 are aligned along axis GD, and a reflector 223 is placed between the light sources 220. Ideally, the reflector 223 is placed equidistantly from the two light sources 220, spanning the axis connecting the two light sources 220.

[0094] Therefore, the two light sources 220 are diametrically opposite each other relative to the reflector 223.

[0095] Therefore, reflector 223 is configured such that it obstructs the passage of light beam 222 as little as possible. Positioned relative to light sources 220 in such a way that, between them, reflector 223 and all its sidewalls 224, 225, 226, 227 extend only on a portion of the perimeter defined around each light source 220. In other words, reflector 223 is adjacent only to one side of each light source 220. Thus, free space is formed on the remaining portion of the perimeter of each light source 220. The light beam 222 reflected by reflector 223 then propagates through this free space formed on the perimeter of each light source 220 without being obstructed by reflector 223.

[0096] In order to reflect at least partially the light beam 222 emitted by the light source 220 toward the region of interest 3, the reflector 223 has a plurality of reflective surfaces 224R, 225R. These reflective surfaces 224R, 225R are placed on the outside of the sidewalls 224, 225 of the reflector 223 toward the light source 220.

[0097] Specifically, each beam 222 emitted by the light source 220 encounters a single reflective surface 224R, 225R in its optical path.

[0098] To reflect the light beam, reflector 223 is at least partially metallized, or may be at least partially covered with a coating having a high albedo. However, some outer surfaces of reflector 223 (such as those resting on walls 226 and 227) may be non-reflective, or even treated to limit stray reflections, for example, by anodizing.

[0099] In the described embodiment, reflector 223 has two reflective surfaces 224R and 225R. These two reflective surfaces 224R and 225R are diametrically opposed to each other and each faces one of the two light sources 220. Specifically, these two reflective surfaces 224R and 225R are at least partially metallized to reflect the light beam 222 by specular reflection. Alternatively, to reflect the light beam 222 by diffuse reflection, a white, matte coating may, for example, cover the two reflective surfaces 224R and 225R.

[0100] After being reflected on the reflective surfaces 224R and 225R of reflector 223, the beam 222 defines the illumination field as equal to the illumination angle. Twice that, as previously described in the specification. As mentioned above, the reflection can be specular or diffuse reflection on the reflective surfaces 224R, 225R of the reflector 223. Here, assuming that the two reflective surfaces 224R, 225R are at least partially metallized, the description focuses on specular reflection.

[0101] The reflective surfaces 224R and 225R of the reflector 223 are at least partially non-planar.

[0102] Preferably, the reflective surfaces 224R and 225R of the reflector 223 have a shape configured such that the illumination field has a larger angular value than the emission field of the light source 220 considered alone without the reflector 223.

[0103] This specifically means that, after being reflected on the reflective surfaces 224R and 225R of the reflector 223, at least a portion of the light 228 from the light beam 222 of one of the light sources 220 is deflected away from the light beam 222 that was originally incident on the reflective surfaces 224R and 225R.

[0104] In other words, after reflection on reflective surfaces 224R and 225R, a portion of the light 228 is deflected beyond the emission cone initially defined by the emission of each light source 220 and propagates through the free space formed around each light source 220. Thus, the deflection of a portion of the light 228 beyond the beam 222 after reflection on reflector 223 enables the illumination field to be expanded relative to the emission field of the individual light source 220.

[0105] Here, in the described embodiment, the reflective surfaces 224R and 225R are selected to be the same. Depending on the variant, different reflective surfaces 224R and 225R may also be selected as a function of the position of the region of interest 3 and / or the position of the illumination module 22 relative to the region of interest 3.

[0106] For example, in the embodiment described herein, reflector 223 has two reflective surfaces 224R, 225R, which are designed to produce an illumination field greater than or equal to 180° along axis GD. In other words, after reflection on one of the reflective surfaces 224R, 225R of reflector 223, at least a portion of the light ray 228 forming beam 222 is reflected at an angle greater than or equal to 90° (in absolute terms) relative to the emission axes A1, A2.

[0107] Specifically, corresponding to the obtained illumination angle The semi-illumination field can be, for example, 97°, where at least a portion of the light ray 228 forms a 97° angle with the emission axes A1, A2 of the associated light source 220. Therefore, this results in an illumination field of 194°.

[0108] Such reflective surfaces 224R and 225R can expand the illumination field relative to the emission field of a single light source 220, and have a precise shape that can be determined experimentally or through a ray tracing simulation process known to those skilled in the art. A simplified explanation of the suitable shape of reflective surfaces 224R and 225R based on geometric optics concepts will be provided in the remainder of this specification.

[0109] The reflective surfaces 224R and 225R of the reflector 223 may have a convex shape, for example, relative to the light source 220 toward which they are oriented.

[0110] In particular, the reflective surfaces 224R and 225R may protrude along several axes and / or have complex morphologies.

[0111] According to one embodiment, such as Figure 3 and Figure 4 As shown, each of the reflective surfaces 224R and 225R has a first curvature along the axis AA'.

[0112] The first convex curvature of the reflective surfaces 224R and 225R along the axis AA' has a vertex.

[0113] Preferably, the light source 220 can be positioned at the vertex of the first convex curvature, such as... Figure 3 As shown.

[0114] The degree of curvature along the axis AA and the exact shape of the surface can be determined experimentally or through a ray tracing simulation process well known to those skilled in the art.

[0115] Here, along axis AA', the reflective surfaces 224R and 225R under discussion have convex curvature, the radius of curvature of which can be between a few millimeters and tens of millimeters. Here, the radius of curvature is chosen to be equal to 10 mm.

[0116] Then, each of the reflective surfaces 224R and 225R can also have a second convex curvature along the axis GD.

[0117] Here, in the disclosed embodiment, each of the two reflective surfaces 224R, 225R discussed has curvature along the two axes AA' and GD.

[0118] Along axis GD, reflective surfaces 224R and 225R first follow curves of a suitable radius, for example, in the described embodiment, the curvature has a radius of several millimeters to tens of millimeters, here chosen to be equal to 1.5 mm. Then, reflective surfaces 224R and 225R extend toward printed circuit board 221 through planar portions.

[0119] However, the present invention is by no means limited to the above-mentioned reflective surfaces 224R and 225R, and those skilled in the art can easily select other surfaces to accommodate various constraints, such as the size of the region of interest, its shape, its distance from the lighting module, whether uniform illumination is required, etc.

[0120] The definitions of non-planar reflective surfaces 224R and 225R can be simply explained using geometrical optics, which allow light rays 228 to be reflected at a reflection angle greater than or equal to 90°, thus providing an illumination field greater than or equal to 180°. These are well known to those skilled in the art, particularly the Snell-Descartes law.

[0121] By defining a normal N at each point on the reflecting surfaces 224R and 225R of the reflector 223, a portion of the ray 228 contained in the beam 222 emitted by the light source 220 is incident at each point on the reflecting surfaces 224R and 225R. An angle of incidence i can then be defined between the normal N and the incident ray 228.

[0122] Then, the incident ray 228 is reflected by the reflecting surfaces 224R and 225R in the plane of incidence containing the normal N and the incident ray 228. The reflected ray 228 has a reflection angle r equal to the angle of incidence i.

[0123] exist Figure 3 and Figure 4 An example of the normal N at a point on the reflecting surface 224R is shown, as are the light rays 228 incident on the reflecting surface 224R and the corresponding reflected light rays 228.

[0124] Therefore, the appropriately shaped reflective surfaces 224R and 225R allow the beam 222 to be partially deflected after reflection, in order to obtain a wider illumination field than the emission field associated solely with the light source 220.

[0125] The above explanation discloses a process conceivable for obtaining reflective surfaces 224R and 225R according to embodiments of the present invention. Within the scope of the invention, more complex modeling and various optimizations of the reflective surfaces 224R and 225R using commercial or non-commercial ray tracing algorithms and software are also possible.

[0126] The reflector 223 can be manufactured in various ways, such as by casting a metallic material, particularly aluminum, or by injection molding a plastic and then depositing a metal layer, for example by vacuum deposition of a metal (e.g., aluminum).

[0127] According to one possible embodiment of the device 2 for monitoring occupants 4 described above, the acquisition module 20 may be mounted within the reflector 223.

[0128] In this embodiment, the acquisition module 20 is nested between the sidewalls 224, 225, 226, and 227 of the reflector 223, and preferably centered within the parallelepiped volume formed by the reflector 223.

[0129] Therefore, the photosensitive sensor of the acquisition module 20 is fastened to the printed circuit board 221 below the imaging optics.

[0130] In the described embodiment, the acquisition module 20 is thus centered among the different light sources 220 (here, there are two). Along axis GD, the order of the elements of the illumination module can be described as follows: first light source 220, then a first reflective surface 224R resting on sidewall 224, then the acquisition module 20, then a second sidewall 225, on which a second reflective surface 225R oriented toward the second light source 220 is resting on its outer surface.

[0131] The above arrangement provides the advantage of a compact device 2 for monitoring occupants 4.

[0132] The assembly formed by the acquisition module 20 and the lighting module 22 (which includes multiple light sources 220, a printed circuit board 221 and a reflector 223) can be contained in a housing covered by a dome 28 made of a material that is optically transparent at the wavelength used in the lighting device 22.

[0133] Other examples of integrating the acquisition module 20 and the lighting module 22 to form the monitoring device 2 can also be envisioned.

[0134] This invention is by no means limited to the embodiments described and illustrated, and those skilled in the art will be able to add any variations thereto according to the invention.

[0135] For example, depending on the lighting requirements, particularly in terms of the luminous intensity or geometry of the area to be illuminated, more light sources 220 may be used in the lighting module 22.

[0136] According to the first variant, in the case of eight light sources 220, the reflector 223 also has eight reflective surfaces 224R, 225R arranged along the sides of the octagon. Each of the reflective surfaces 224R, 225R is then oriented toward one of the light sources 220 in order to reflect the beam 222 emitted by it.

[0137] According to the second variation, while still having eight light sources 220, the reflector 223 has four reflective surfaces 224R, 225R arranged along the sides of a parallelepiped. Each of the reflective surfaces 224R, 225R will then be oriented toward two light sources, and each reflective surface will thus reflect two beams 222.

Claims

1. A lighting module (22), comprising: - At least one light source (220) is designed to emit a beam (222) consisting of a set of light rays (228), each of the light sources (220) being provided with a periphery. - A reflector (223) having at least one reflective surface (224R, 225R) arranged to at least partially reflect the light beam (222). The reflector (223) is characterized in that it extends only on a portion of the periphery of the at least one light source (220) to form a free space, and the at least one reflective surface (224R, 225R) is arranged such that after reflection on the at least one reflective surface (224R, 225R), at least a portion of the ray (228) of the light beam (222) is reflected outside the light beam (222) emitted by the at least one light source (220), and the portion of the ray (228) passes through the free space formed on the periphery of the at least one light source (220).

2. The lighting module (22) according to claim 1, wherein, The at least one reflective surface (224R, 225R) is at least partially non-planar.

3. The lighting module (22) according to claim 2, wherein, The at least one reflective surface (224R, 225R) is convex relative to the at least one light source (220), and the at least one reflective surface (224R, 225R) is arranged relative to the at least one light source to at least partially reflect the light beam (222).

4. The lighting module (22) according to any one of claims 1 to 3, wherein, The at least one light source (220) emits in a direction referred to as the illumination direction, and the ray (228) corresponding to the portion of the ray (227) reflected outside the light beam (222) forms an angle greater than or equal to 90° with the illumination direction.

5. The lighting module (22) according to any one of claims 1 to 4, wherein, The lighting module (22) includes a plurality of light sources (220), and wherein the reflector (223) includes a plurality of reflective surfaces (224R, 225R), and the lighting module (22) has a central region, wherein the plurality of reflective surfaces (224R, 225R) of the reflector (223) are positioned in the central region, the central region is surrounded by a peripheral region, and the plurality of light sources (220) are positioned in the peripheral region such that the reflector (223) is surrounded by the plurality of light sources (220).

6. The lighting module (22) according to claim 5, wherein the lighting module (22) includes a printed circuit board (221), and wherein the plurality of light sources (220) are fastened to the printed circuit board (221).

7. The lighting module (22) according to any one of claims 1 to 6, wherein, The reflector (223) is integrally formed.

8. The lighting module (22) according to any one of claims 1 to 7, wherein, The at least one light source (220) includes at least one light-emitting diode.

9. A device (2) for monitoring the occupants (4) of a motor vehicle (1), comprising an acquisition module (20) capable of imaging a region of interest (3) at least partially illuminated by an illumination module (22) according to any one of claims 1 to 8.

10. The monitoring device (2) according to claim 9, comprising the lighting module (22) according to any one of claims 5 and 6, wherein, The acquisition module (20) is placed in the central area of ​​the lighting module (22).

11. The monitoring device (2) according to any one of claims 9 and 10, comprising the lighting module (22) according to any one of claims 5 and 6, wherein, The acquisition module (20) is at least partially surrounded by the reflector (223), and the plurality of light sources (220) are arranged around the acquisition module (20).

12. The monitoring device (2) according to any one of claims 9 to 11, wherein, The motor vehicle (1) includes a passenger compartment, and the region of interest (3) includes at least part of the front space of the passenger compartment of the motor vehicle (1).

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