Optical systems for vehicle interior lighting

Abstract

The invention relates to an optical system (1, 2) for the interior lighting of a motor vehicle (100), the optical system comprising a screen (6) and a plurality of light sources (32) arranged in a string, the plurality of light sources being designed to project light beams onto the screen, the optical system (1, 2) comprising a light box (4) between the plurality of light sources and the screen, the light box comprising a plurality of recesses (8), each light source (32) being associated with a recess (8) in the light box (4), each light source being independently activatable. The invention also relates to a motor vehicle (100) comprising an interior lighting device (115) comprising such an optical system (1, 2). The invention is applicable to motor vehicles.

Description

Technical Field

[0001] The field of the invention is that of optical systems intended in particular to illuminate the interior of a passenger compartment of a vehicle, in particular a motor vehicle. Background Art

[0002] Such optical systems known in the prior art include a light source, a screen and a light guide located between the screen and the light source. The light source causes a light beam to be emitted, the light guide homogenizes the light beam and routes it to the screen, which finally diffuses the light beam.

[0003] These known optical systems are not entirely satisfactory and have disadvantages. In fact, the use of known light guides requires minimum overall dimensions in order to homogenize the light beam well before transmitting it to the screen, which overall dimensions are not always compatible with the constraints related to the available space or the geometry of the location where the optical system must be installed in the passenger compartment of a motor vehicle. Moreover, the internal volume of the light guide in which the light beam emitted by the light source moves is filled with the material constituting the light guide, usually polymethyl methacrylate (PMMA), which causes the light beam inside the light guide to be refracted, which refraction may disturb the homogenization of the light beam in the light guide. Summary of the invention

[0004] The object of the present invention is to propose an optical system which is able to at least partially overcome the above-mentioned disadvantages and also has other advantages. It is therefore an object of the present invention to allow the use of an optical system in confined spaces which do not allow the use of known light guides, in particular to allow the use of an optical system in the form of a strip which therefore has a main dimension along the longitudinal axis of the optical system and a secondary dimension along an axis perpendicular to the longitudinal axis, the main dimension being significantly greater than the secondary dimension, while ensuring that the optical system satisfactorily homogenizes the light beam. In addition, it is an object of the present invention to be able to obtain dynamic lighting, in which a plurality of light sources of the optical system can be switched on and / or off in succession in order to display information and / or to create ambient lighting effects in the passenger compartment of a motor vehicle.

[0005] In a first aspect, the present invention achieves this object by an optical system for interior lighting of a motor vehicle, the optical system comprising a screen and a plurality of light sources arranged in a string, the plurality of light sources being configured to project light beams onto the screen, characterised in that the optical system comprises a light box between the plurality of light sources and the screen, the light box comprising a plurality of cavities, each light source being associated with a cavity of the light box, and each light source being capable of being independently activated.

[0006] Interior lighting of a motor vehicle is intended to illuminate the interior of the passenger compartment of the motor vehicle.

[0007] The string arrangement of the plurality of light sources forms the longitudinal axis of the optical system. It should be understood that the string arrangement of the light sources refers to the positioning of the light sources in the plurality of light sources one after another, forming a curve or a straight line, rather than the type of circuit powering the light sources.

[0008] A plurality of light sources, light boxes and screens are stacked in sequence along a stacking axis perpendicular to the longitudinal axis.

[0009] The optical system forms a luminous strip. In practice, the optical system extends along a vertical axis perpendicular to the plane formed by the longitudinal axis and the stacking axis, preferably over a distance between 6 mm and 25 mm (inclusive), while the optical system extends along the longitudinal axis over a distance preferably greater than 20 cm. The optical system preferably extends on the stacking axis over a distance between 5 mm and 40 mm (inclusive).

[0010] The light box defines an interior volume filled with air, which is bounded by walls having reflective properties. Thus, a light beam emitted from the light source is deflected only by one or more reflections from the walls of the light box before being projected onto the screen.

[0011] Thus, the light box according to the invention is different from a light guide, which also defines an internal volume delimited by walls, but which is filled with the material constituting the walls of the light guide, such as polymethyl methacrylate (PMMA). According to the invention, in contrast to the light beams moving in known light guides, the light beams are not refracted in the light box, since the light box is filled with air.

[0012] The light box comprises a plurality of cavities arranged one after another along a longitudinal axis, each of which is bounded by a reflective wall formed by the material constituting the light box. Thus, the reflective wall defining each cavity is capable of guiding the light beam emitted by the light source, in particular to the area of ​​the screen facing the cavity, the light source being located inside the cavity or at the edge of the cavity, so as to emit the light beam into the cavity. Thus, the wall of the first cavity is configured so that the light beam emitted by the first light source present in the first cavity is projected to the height of the screen area facing the first cavity. Thus, the wall of the first cavity prevents the light beam emitted by the first light source from being projected to the height of the screen area facing the second cavity, the second cavity being in particular adjacent to the first cavity. Thus, the wall of the cavity is capable of preventing the light beam emitted by the light source located in the cavity from being at least partially projected into another cavity.

[0013] Each light source can be activated and / or deactivated independently of the other light sources, thus forming a matrix light beam that can be activated selectively. For example, a first light source can be activated and then emit a light beam, while an adjacent light source is deactivated and does not emit a light beam. This can thus illuminate or extinguish different areas of the screen and produce a light matrix whose shape can be changed at will.

[0014] Finally, in this configuration according to the invention, the optical system does not comprise supplementary optics between the light source and the screen for homogenizing the light beam.

[0015] The optical system according to the first aspect of the present invention advantageously includes at least one of the following improvements, the technical features forming these improvements being adopted individually or in combination:

[0016] - The cavity comprises an elliptical profile in a first plane, the first plane being perpendicular to the screen and passing through the light source associated with the cavity. The screen area associated with the cavity is defined as an area extending along a first axis and a second axis perpendicular to each other, the screen area comprising a short side on the first axis and a long side on the second axis, the short side being defined by a smaller dimension than the long side. In particular, the first axis is a "vertical axis" and the second axis is a "longitudinal axis". The cavity has an elliptical profile in a first plane, the first plane being perpendicular to the screen and passing through the light source associated with the cavity and including the first axis. Thus, the elliptical profile of the cavity may facilitate the reflection of the light of the light beam so as to concentrate the light at the height of the screen, the concentration of the light being consistent with the vertical configuration, i.e. along the first axis. Thus, according to this configuration, the elliptical profile of the cavity causes the reflected light to be concentrated at the center of the screen in the vertical direction (i.e. in a direction perpendicular to the stacking axis and the longitudinal axis).

[0017] - The cavity comprises a parabolic profile in a second plane, the second plane being perpendicular to the screen and passing through the light source associated with the cavity. According to the above description, the screen area associated with the cavity is defined as an area extending along a first axis and a second axis perpendicular to each other, the screen area comprising a short side on the first axis and a long side on the second axis, the short side being defined by a smaller dimension than the long side. In particular, the first axis is a "vertical axis" and the second axis is a "longitudinal axis". The cavity has a parabolic profile in a second plane, the second plane being perpendicular to the screen and passing through the light source associated with the cavity and comprising the second longitudinal axis. The parabolic profile of the cavity enables the rays of the light beam to be collimated and arranged in a plane comprising the second longitudinal axis, thereby enabling the light beam to be uniformly distributed along the longitudinal axis at the height of the screen area facing the light source in the cavity generating the light beam. By giving each cavity such a parabolic profile, a uniform distribution of the light beam is gradually obtained over the entire length of the strip forming the screen surface.

[0018] The optical system advantageously comprises an elliptical profile in a first plane and a parabolic profile in a second plane. Thus, this configuration enables both the concentration of the light at the height of the screen due to the elliptical profile and the collimation of the light beam emitted by the light source due to the parabolic profile.

[0019] The first plane and the second plane are perpendicular to each other. The first plane advantageously extends along the stacking axis and the vertical axis, the second plane advantageously extends along the stacking axis and the longitudinal axis, the vertical axis being parallel to the short side of the screen area, the longitudinal axis being parallel to the long side of the screen area.

[0020] -The light source is an RGB light source and / or an RGBW light source. Each RGB light source can emit a red, green or blue light beam, or a combination of red, green and / or blue light beams. The RGBW light source can also emit a white light beam generated by an appropriate wavelength conversion device alternatively or cumulatively. According to the configuration, the plurality of light sources can include only RGB light sources or only RGBW light sources, or a combination of RGB light sources and RGBW light sources. Each light source can in particular be a light emitting diode (LED).

[0021] -The light box comprises a dimension along the stacking axis, which dimension is variable between the first longitudinal end and the second longitudinal end. This construction enables the method for manufacturing the optical system to be facilitated. In practice, the light sources are mounted on a printed circuit. The use of a printed circuit situated in a single plane enables the method for manufacturing the optical system to be facilitated, thereby reducing its manufacturing costs. According to this construction, the light box is able to compensate for differences in plane between a first area of ​​the screen and a second area of ​​the screen, for example when the screen has a curve along the longitudinal axis, while the printed circuit on which the light sources are mounted extends parallel to the longitudinal axis. Compensation of differences in plane is more specifically obtained by changing the profile of the cavity, in particular by changing the elliptical profile and / or the parabolic profile of the cavity, or also by changing the dimensions of the light box along the stacking axis.

[0022] - the ratio between a first dimension associated with the wall of the cavity and a second dimension associated with the light box is between 40% and 85% (inclusive), the first dimension and the second dimension being measured parallel to the stacking axis. More specifically, the first dimension is measured between the bottom of the cavity (i.e. near the light source) and the free end of the wall opposite the cavity with respect to the bottom. The second dimension is measured between the bottom of the cavity and the portion of the light box that receives the screen.

[0023] -The inner surface of the wall is covered with a material that enables both specular and diffuse reflection of the light beam. The inner surface of the wall is the surface of the wall facing the interior of the cavity. In other words, the inner surface of the wall is exposed to the light of the light beam emitted by the light source present in the cavity. The material is advantageously white and is therefore able to reflect all wavelengths of the light beam. For example, the material can be the following material: ALBIS ALCOM PWL 10 / 1.1 WT1302-05LB. This material is advantageous because it provides a good compromise between specular reflection and diffuse reflection. Therefore, when the light beam is projected onto the material, the ratio between specular reflection and diffuse reflection is between 5% specular reflection (corresponding to 95% diffuse reflection) and 40% specular reflection (corresponding to 60% diffuse reflection) - including the end values. Therefore, materials with similar or similar properties can improve the uniformity of the light of the light beam. In addition, it is worth noting that according to the invention, in a configuration including an elliptical and / or parabolic profile, the light source must theoretically be located at the height of the object focus of the profile. However, using a light box whose inner surface of the wall is covered with such a material enables flexibility in the theoretical arrangement of the light sources at the height of the object focal point.

[0024] - The inner surface of the wall comprises a plurality of diffusing microstructures. The diffusing microstructures can allow diffuse reflection, which can double the diffuse reflection, in particular compared to a configuration in which the inner surface of the wall does not have diffusing microstructures. The diffusing microstructures can thus improve the uniformity of the light beam at the level of the light box. For example, the diffusing microstructures can take the form of pads extending from the inner surface of the wall towards the interior of the cavity.

[0025] The diffusing microstructures may be located on an elliptical profile and / or a parabolic profile of the inner surface of the wall.

[0026] - Preferably, the diffusing microstructure is located in the proximal part of the cavity, that is to say in the vicinity of the light source along the stacking axis.

[0027] The screen is a diffusive screen. This configuration makes it possible to homogenize the chromaticity and / or brightness of the light beams over the height of each area of ​​the screen.

[0028] -The optical system comprises a control module configured to give instructions for selectively activating the light sources so as to be able to display a dynamic and / or multi-colored light signal. The light signal corresponds to the projection on the screen of an overall light beam formed by all the individual light beams emitted by each light source. Thus, the light signal is dynamic if the overall light beam is changed in time by illuminating and extinguishing different screen areas. The band formed by the optical system preferably extends on the longitudinal axis for a distance preferably greater than 20 centimeters, so that the dynamic effect imparted to the light signal can be perceptible to the passengers in the motor vehicle. If the light signal has two different colors at the level of two different screen areas, the light signal is multi-colored. Thus, the optical system can be used, for example, as a turn indicator repeater or as an indicator of certain objects present in the blind spot of the vehicle. Thus, in the latter example, an object present in the blind spot (for example another motor vehicle) can be represented by a light signal moving on the screen.

[0029] According to a second aspect, the invention also comprises a motor vehicle comprising an interior lighting arrangement comprising an optical system in accordance with the first aspect of the invention.

[0030] Therefore, this construction according to the second aspect makes it possible for a motor vehicle to include an optical system in accordance with the first aspect, thereby making it possible to install the optical system according to the invention in a position in the passenger compartment where it would not be possible to install known optical systems, in particular due to limitations on the overall spatial dimensions of known optical systems.

[0031] In a motor vehicle according to the second aspect of the invention, the optical system is advantageously a strip on a door and / or panel of the motor vehicle. This configuration makes the optical system visible to the driver and / or a passenger of the motor vehicle. Thus, the driver and / or the passenger can receive information via the light signal, which information, for example, relates to the situation of the road scene. Alternatively or cumulatively, the optical system can be located at any other location in the passenger compartment of the motor vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Other characteristics, details and advantages of the invention will become more apparent on reading the following description of an embodiment given by way of non-limiting illustration with reference to the accompanying drawings, in which:

[0033] - Figure 1 and Figure 2 shows a perspective view of a passenger compartment of a motor vehicle according to a second aspect of the invention, Figure 1 and Figure 2 Two embodiments of an optical system for a motor vehicle are shown;

[0034] - Figure 3is a partial perspective view of an embodiment of an optical system consistent with the first aspect of the present invention;

[0035] - Figure 4 Shows Figure 3 Details of the optical system shown;

[0036] - Figure 5 is a cross-sectional view of an embodiment of an optical system according to the first aspect of the present invention, the cross-sectional view being located on a cross-section plane containing the longitudinal axis and the stacking axis;

[0037] - Figure 6 The cavity of an embodiment of an optical system according to the first aspect of the invention is schematically shown in a plane containing a vertical axis and a stacking axis;

[0038] - Figure 7 The cavity of an embodiment of an optical system according to the first aspect of the invention is schematically shown in a plane containing the longitudinal axis and the stacking axis;

[0039] - Figure 8 is a perspective view of another embodiment of an optical system consistent with the first aspect of the present invention. DETAILED DESCRIPTION

[0040] The features, variants and various embodiments of the invention can be associated with each other according to different combinations, as long as they are not incompatible or mutually exclusive. It is particularly possible to imagine a variant of the invention that only includes the selection of the features described below separately from the other features described, if the selection of this feature is sufficient to give a technical advantage or to distinguish the invention from the prior art.

[0041] In particular, all variants and all embodiments described can be combined with one another, if the combination is not opposed from a technical point of view.

[0042] Figure 1 and Figure 2 shows a perspective view of a passenger compartment 110 of a motor vehicle 100 in accordance with a second aspect of the invention, Figure 1 and Figure 2 Two operating modes of the optical system of the motor vehicle 100 are shown.

[0043] The passenger compartment 110 of the motor vehicle 100 comprises a first seat 111 and a second seat 112, the first seat facing the steering wheel 113 and intended to receive the driver of the motor vehicle, and the second seat intended to receive a passenger. The passenger compartment also comprises a windscreen 114, which enables the passenger of the motor vehicle to perceive the road scene in front of the vehicle (AV). The motor vehicle also comprises an internal rearview mirror 116 located inside the passenger compartment and an external rearview mirror 118 located outside the passenger compartment, the internal rearview mirror 116 and the external rearview mirror 118 enabling the conductor to perceive the road scene behind the vehicle (AR), the front AV and the rear AR being defined relative to the main direction of movement of the motor vehicle 100.

[0044] The passenger compartment comprises a first optical system 1 and a second optical system 2, which are mounted in the form of a strip on a door 120 and a panel 122 of a motor vehicle, respectively, the panel representing a portion of the passenger compartment located in front of a first seat and a second seat and extending between the right and left sides of the passenger compartment. For example, the panel comprises an instrument panel facing the driver and comprising a plurality of indicators (e.g., a vehicle speed or engine speed indicator), and the panel may also comprise one or more vents facing the driver and / or the passenger. The first optical system 1 and the second optical system 2 are part of an interior lighting device 115 of the vehicle, which interior lighting device 115 may also comprise, for example, a lamp on the ceiling of the passenger compartment or a lamp in the glove box.

[0045] Each optical system 1, 2 comprises a plurality of distinct display surfaces or screen areas 124, each screen area being associated with a light source of the optical system 1, 2. Each optical system thus forms a band having a major dimension on the longitudinal axis of the optical system and a smaller secondary dimension on an axis perpendicular to the longitudinal axis of the optical system. Figure 1 and Figure 2 A control module is shown in the figure, which is configured to issue instructions for selectively starting the light sources of the optical system, thereby enabling the generation of a dynamic and / or multi-color light signal at the height of the optical system, which corresponds to all light beams generated by the light sources of the optical system.

[0046] Figure 1 A standby operating mode is shown, in which no specific driving situation is detected. In this case, the first optical system 1 and the second optical system 2 are inactive, the light sources of the first optical system 1 and the second optical system 2 are extinguished and therefore no light beam is emitted. As a result, the first optical system 1 and the second optical system 2 do not generate any light signal. Obviously, as an alternative, the first optical system 1 and / or the second optical system 2 can also be configured to generate a standby light signal, which does not indicate any specific driving situation, which light signal may then be static and / or monochromatic.

[0047] Figure 2 An active operating mode is shown, in which a specific driving situation has been detected. More specifically, in the example shown, the first optical system 1 is made active, the second optical system 2 is inactive or in its previous state in the standby operating mode. In fact, a first part 126 of the light sources of the first optical system is lit, each of which emits a light beam that passes through the display surface or the corresponding screen area. On the contrary, the second part 128 of the light source of the first optical system 1 is extinguished and does not emit any light beam. Therefore, in this active operating mode, it is obvious that the illumination of one or more light sources of one and / or another of the optical systems is controlled so that the light signal can be displayed to the extent of a larger or smaller part of each optical system. As described in more detail below, by lighting and then extinguishing the light sources arranged sequentially in the longitudinal direction, a dynamic signal can be generated, that is to say, a signal whose structure changes over time according to the display surface or screen area that is lit or extinguished.

[0048] exist Figure 2 In the driving situation shown, the light signal displayed by the first optical system 1 can, for example, indicate the presence of a certain element, in particular another vehicle, on the left side of the motor vehicle 100 relative to the direction AV of the forward movement of the motor vehicle. Thus, the sequential lighting of the various light sources of the first optical system makes it possible to schematically represent the position of an element relative to the motor vehicle 100 along an axis extending between the front AV and the rear AR of the motor vehicle 100. For example, the first optical system enables the driver of the motor vehicle 100 to determine that they can perform a certain maneuver, in particular in order to change lanes safely and securely, by giving him visual information supplementary to that provided by the interior rearview mirror and the exterior rearview mirror. In fact, this configuration enables the driver to avoid taking his eyes off the road scene located in front of the vehicle (AV), in particular in order to observe a blind spot located on the left side of the driver, which corresponds to the driver's field of vision that is neither covered by their direct field of vision nor by the field of vision provided by the interior rearview mirror 116 or the exterior rearview mirror 118. In this example, the second optical system 2 is inactive, in particular because no element is detected on the right side of the motor vehicle 100.

[0049] The first optical system 1 thus enables the driver of the motor vehicle to be informed that they can Figure 1 Safely execute a left lane change maneuver in the driving situation shown in the figure, which Figure 2 The driving situation shown represents a hazard, in particular a potential collision.

[0050] Figure 3is a partial perspective view of an embodiment of an optical system 1, 2 according to the first aspect of the present invention.

[0051] The optical system 1, 2 extends along a main longitudinal axis X. The optical system 1, 2 comprises a light box 4, a plurality of light sources and a screen 6, which are superimposed in a superposition direction Y perpendicular to the longitudinal axis X. The screen 6 is intended to be oriented towards the interior of the passenger compartment of the motor vehicle, that is to say to be arranged between the passenger compartment and the light box 4, so as to enable the scattering of light signals intended for the passengers of the motor vehicle. The optical system preferably extends at least 20 centimeters on the longitudinal axis X, while the optical system preferably extends 6 to 25 millimeters (inclusive) on a vertical axis perpendicular to the plane formed by the longitudinal axis X and the superposition axis Y, so that the optical system 1, 2 forms a luminous strip.

[0052] The light box defines an internal volume 12 filled with air and delimited by walls 14. The light box 4 comprises a plurality of cavities 8 arranged in a string along a longitudinal axis and delimited from one another by walls 14. The walls more particularly comprise a plurality of undulations defining a proximal end 16 of the cavity on the stacking axis Y, forming the bottom of the cavity, and a distal end 17 forming the end of the demarcation between two adjacent cavities. The optical system 1 comprises Figure 3 A plurality of light sources not visible in the cavity 8 are provided, each of which enables a light beam to be emitted inside the cavity 8. The inner volume 12 is filled with air, and the light beams emitted by the light sources are not refracted in the light box 4 on their way from the light source to the screen.

[0053] In the embodiment shown, the optical system 1, 2 comprises a printed circuit 10 which is located opposite the optical system relative to the screen 6 on the stacking axis Y. The proximal end 16 is therefore located near the printed circuit 10. The printed circuit 10 electrically connects each light source of the optical module to a control module not shown here, in order to control the supply of electrical power to each light source, thus enabling independent lighting and extinguishing of each light source of the optical system. The printed circuit 10 is composed of a plurality of segments 7 (in Figure 3 Three segments 7 can be seen in the figure). Using a printed circuit 10 formed in a plurality of segments 7 makes it possible to give the printed circuit 10 a certain flexibility and to mount the printed circuit in curved areas of a vehicle.

[0054] Figure 4 yes Figure 3 A perspective view of a partial detail of the optical system shown.

[0055] Each light source 32 of the optical system 1, 2 is associated with the cavity 8 of the light box 4. Each light source more particularly projects from the printed circuit 10, and the wall 14 is provided with an orifice at the level of the proximal end 16 of each cavity, so as to surround the respective light source, the proximal end 16 of the cavity being the portion of the cavity that is at the greatest distance from the screen 6 along the stacking axis Y. The light sources may be arranged inside the cavity 8 or at the edge, as long as they enable the emission of a light beam inside the cavity. Each light source 32 is, for example, an RGB light source, thus enabling the emission of a red, green, blue light beam or a combination of red, green and blue light beams inside the cavity, thereby enabling the formation of a polychromatic light beam.

[0056] exist Figure 3 and Figure 4 In the embodiment shown, the bottom of the cavity 8 is located near the printed circuit 10. The proximal end 16 of the cavity thus forms a first terminal end of the light box 4; the second terminal end 22 of the light box 4 is located at the side of the light box opposite to the first terminal end along the stacking axis Y, so that the second terminal end 22 receives the screen 6.

[0057] The walls 14 of the light box make it possible to reflect the light beams emitted by each light source. The walls that delimit each cavity 8 more particularly make it possible to reflect the light beams emitted by the light sources associated with this cavity so that the light beams are projected at the height of the display surface or screen area positioned along the longitudinal axis X facing this cavity. Thus, the walls of the first cavity 9 make it possible for the light beams emitted by the light sources located at the height of this first cavity 9 to be projected at the height of the first screen area 125 positioned along the longitudinal axis X facing this first cavity 9. In a similar way, the walls of the second cavity 11 adjacent to the first cavity 9 make it possible for the light beams emitted by the light sources located at the height of this first cavity 11 to be projected at the height of the second screen area 127 positioned along the longitudinal axis X facing this second cavity 11. Obviously, as a result, the portion of the wall 14 that makes it possible to delimit each cavity 8 makes it possible for the light beams emitted by the light sources associated with this cavity 8 to be prevented from being projected at the height of the screen area offset relative to this cavity along the longitudinal axis.

[0058] In order to facilitate this feature and to ensure that the portion of the wall disposed between the two cavities adequately blocks the light that tends to pass from one cavity to the other, the optical system is configured so that the ratio between a first dimension 18 associated with the wall of the cavity and a second dimension 19 associated with the light box, both measured along the stacking axis, is between 40% and 85% (inclusive). In other words, the first dimension 18 is measured between the proximal end 16 of the cavity (which forms the bottom of the cavity, close to the light source associated with the cavity) and the distal end 17 of the cavity (which is located on the opposite side of the cavity relative to the proximal end 16 on the stacking axis Y). The second dimension 19 corresponds to the overall transverse dimension of the light box 4 measured between the proximal end 16 of the cavity and the second terminal 22 carrying the screen. This configuration thus enables the projection of the light beam emitted by the light source associated with the cavity to be maximized on the screen area facing the cavity, thereby enabling the projection of the light beam emitted by the light source associated with the first cavity 9 to be projected to the height of the second screen area 127. Thus, this configuration enables a clear division of the light signal generated by the optical systems 1, 2, which configuration is particularly interesting, in particular when the light signal is dynamic and / or polychromatic, and each light source of the optical systems 1, 2 can be activated independently. The ratio between the first dimension 18 and the second dimension 19 is advantageously adjusted to enable a small overlap of the light beams emitted by the light source associated with the first cavity 9 to the second screen area 127, thereby enabling an improved uniformity of the light signal generated by the optical systems 1, 2. Thus, a portion of the light emitted by the light source associated with the first cavity is projected onto the second screen area. In other words, a portion of the wall disposed between the two cavities substantially but not completely blocks light that is easily transferred from one cavity to the other.

[0059] Figure 5 It is a cross-sectional view of an embodiment of the optical system 1, 2 according to the first aspect of the present invention, the cutting plane E contains the longitudinal axis X and the stacking axis Y; the plane E, referred to as the second plane E, is perpendicular to the first plane D, which contains the vertical axis Z and the stacking axis Y.

[0060] The cavity 8 has a parabolic profile 37 in the second plane E. In fact, the trajectory of the portion of the wall 14 that delimits the cavity in the second plane E is a parabola. More specifically, the trajectory of the portion of the wall that delimits the cavity is a parabola extending from one distal end 17 via the proximal end 16 to the other distal end. In addition, the cavity 8 has an elliptical profile in the first plane D, the trajectory of the portion of the wall that delimits the cavity in the first plane D is an ellipse. Figure 6 The oval outline can be better seen in the

[0061] Associated with the cavity is a light source 32, which is located near the proximal end 16 of the cavity. Figure 6In the example shown, the light source is located inside the cavity 8, that is to say inside the inner volume 12 of the light box 4. Activation of the light source 32 enables a light beam to be emitted which is projected onto the screen 6 at the location where it would have reached after being reflected from the walls 14 defining the cavity.

[0062] The inner surface 15 of the wall 14 is covered with a reflective material capable of reflecting the light beam emitted by the light source 32, and the inner surface 15 of the wall is positioned toward the interior of the cavity 8. In other words, the inner surface 15 is exposed to the light beam emitted by the light source. The reflective material covering the inner surface 15 of the wall 14 is preferably white, thereby facilitating the reflection of all wavelengths of the light beam emitted by the light source 32.

[0063] The inner surface 15 of the wall 14 comprises a plurality of diffusing microstructures 24 located on the elliptical contour of the cavity 8. The diffusing microstructures 24 facilitate diffuse reflection of the rays of the light beam at the level of the cavity, thereby facilitating the homogenization of the light beam within the light box 4. When the incident rays of the light beam encounter the wall at the height of the diffusing microstructures, they are thus reflected as a large number of diffusely reflected rays, thereby homogenizing the light beam at the level of the cavity. In the example shown, the diffusing microstructures extend between the proximal end 16 of the cavity and the second terminal end 22 of the light box 4, forming a bead extending from the inner surface 15 towards the inside of the cavity.

[0064] Figure 6 Schematic diagram of an embodiment of the optical system 1, 2 in the aforementioned first plane D in accordance with the first aspect of the present invention.

[0065] therefore, Figure 6 It makes it possible to visualize the reflection on the elliptical profile 35 of the wall 14 of a ray 30 forming a beam emitted by a light source 32 associated with the cavity 8 , which ray can be reflected from the inner surface of the wall before being projected onto the screen 6 .

[0066] The elliptical profile 35 of the wall delimiting the cavity in the first plane D, which is situated only partially on the wall delimiting the cavity and, in particular, near the proximal end 16, comprises a rectilinear profile 36 near the distal end 17, which is substantially parallel to the axis of overlap Y. In fact, the light source 32 is situated in the first plane D near the first focus of the ellipse described by the wall 14, and a portion of the screen 6 is situated near the second focus of the ellipse. Thus, when an incident ray 31 encounters the inner surface of the wall 14 forming the elliptical profile, the incident ray 31 is reflected in the direction of the screen 6, forming a reflected ray 33. The elliptical profile 35 of the wall 14 is able to reflect the incident ray 31 so that all the reflected rays 33 converge on a point forming the second focus of the ellipse, near which the screen 6 is situated. Thus, the elliptical profile of the wall 14 of the cavity 8 in the first plane D enables the light rays 30 to be concentrated in a central zone 34 of the screen 6, situated at the centre of the screen 6 on the vertical axis Z, that is to say at the centre on the short side of the screen zone 124 associated with this cavity 8. This feature enables coordination of the light signal, that is to say ensures that the occupants of the vehicle do not notice the vertical offset of the light signal from one screen zone to another. By centreing the light rays emerging from each screen zone, the aim is to promote vertical continuity of the signal and therefore to produce a coordinated signal, both in the case of static light signals and in the case of dynamic light signals in which the signal is transmitted by successive lighting up and extinguishing of adjacent screen surfaces.

[0067] Figure 7 is a schematic diagram of a cavity 8 in a second plane E of an embodiment of an optical system 1 , 2 according to the first aspect of the present invention.

[0068] therefore, Figure 7 It makes it possible to visualize the reflection of a ray 30 from the parabolic profile 37 of the wall 14 , this ray forming a beam emitted by a light source 32 associated with the cavity 8 , this ray being able to reflect from the inner surface of the wall before being projected onto the screen 6 .

[0069] The parabolic profile 37 of the portion of the wall delimiting the cavity in the second plane E more particularly enables the light beam formed by all the light rays 30 emitted by the light source 32 to be collimated. In fact, the light source is located near the focus of the parabola described by the parabolic profile 37 of the wall 14 in the second plane E. When the incident light ray 31 encounters the inner surface of the wall 14 forming the parabolic profile, the incident light ray 31 is then reflected in the screen direction, forming the reflected light ray 33. The parabolic profile 37 of the wall 14 in the second plane E enables the incident light ray 31 to be reflected so that all the reflected light rays 33 are parallel to each other and to the superposition axis Y. Therefore, the parabolic profile 37 of the wall in the second plane E enables the light beam, in particular the chromaticity and brightness of said light beam, to be evenly distributed over the entire screen area 124 on the longitudinal axis X, i.e. on the long sides of the screen area 124. The light source may be an RGB or RGBW light source as described above, and a uniform polychromatic light beam can be obtained by homogenizing the chromaticity of the light beam emitted by the light source, that is, when its hue is uniform on the longitudinal axis X over the entire screen area 124 .

[0070] It can be noted that, in particular, reference Figure 6 and Figure 7 , the range of the portion of the wall including the elliptical profile is smaller than the range of the portion of the wall including the parabolic profile.

[0071] On the one hand, the elliptical profile is in a first plane D containing the vertical axis Z. Now, the overall size is limited by the segment, and this defines a smaller size of the screen area onto which the light signal is projected.

[0072] On the other hand, the use of a parabolic profile in the second plane E containing the longitudinal axis X makes it possible to increase the longitudinal size of the screen area illuminated by the same light source, which, for a given optical system length, makes it possible to reduce the number of light sources in the optical system and thus reduce the production costs of such an optical system.

[0073] from Figure 6 and Figure 7 It is clearly seen that the optical system 1 , 2 according to the invention makes it possible to dispense with additional optics, such as optical lenses, inserted between the light source 32 and the screen 6 in order to homogenize and collimate the light beam inside the cavity 8 .

[0074] Figure 82 is a perspective view of another embodiment of an optical system 1, 2 in accordance with the first aspect of the present invention. The light box 4 of the embodiment shown in the figure has a variable dimension along the stacking axis Y between the first longitudinal end 26 and the second longitudinal end 28. In other words, the second dimension 19 measured between the proximal end 16 and the second terminal end 22 of the light box 4 is variable along the longitudinal axis X. As shown in the figure, the second dimension measured at the height of the first longitudinal end 26 forms a first depth 27, and the second dimension measured at the height of the second longitudinal end 28 forms a second depth 29, and from Figure 8 As can be seen in FIG. 1 , the first depth 27 is greater than the second depth 29. This construction can be achieved as follows: on the one hand, by using a flexible and / or segmented printed circuit to optimally adapt the position of each light source as close as possible to the focus of the ellipse and / or parabola of the cavity; on the other hand, by using a reflective material covering the inner surface of the wall, the light beam can be partially diffused, thereby allowing a certain flexibility in positioning the light source 32 and / or the screen 6 relative to the focus of the ellipse of the elliptical profile 35 and / or the focus of the parabola of the parabolic profile 37 of the wall 14 of the cavity 8, so that the optical system can present a curve in order to meet the constraints, especially the overall size constraints; in the passenger compartment of a motor vehicle, the optical system is in the form of a strip extending for a large length along the longitudinal axis X, and is therefore affected by the curve of the structural elements used to house the optical system.

[0075] The invention just described achieves the objectives set for it and makes it possible to propose an optical system of simple design and small overall dimensions, making it possible to homogenize the light beam it generates. Variants not described here can be developed without departing from the context of the invention, provided that, according to the invention, the optical system comprises a light box comprising a plurality of cavities, each of which is associated with a light source that can be activated independently.

Claims

1. An optical system (1, 2) for interior lighting of a motor vehicle (100), the optical system (1, 2) being mounted in the form of a strip on a door (120) and a panel (122) of the motor vehicle and comprising a screen (6) and a plurality of light sources (32) arranged in a string, the plurality of light sources being configured to project light beams onto the screen (6), characterized in that The optical system comprises a light box (4) between the plurality of light sources and the screen, the light box (4) comprising a plurality of cavities (8), each light source (32) being associated with a cavity (8) of the light box, each light source (32) being independently activatable; wherein the light box defines an internal volume filled with air and bounded by walls, and the walls comprising a plurality of undulations, the plurality of undulations defining a proximal end (16) and a distal end (17) of the cavity on a stacking axis (Y), the proximal end forming the bottom of the cavity, wherein the proximal end (16) is positioned close to the end of the light source (32) facing the screen (6), wherein the screen (6) is a diffusing screen, wherein the cavity (8) comprises an elliptical profile (35) in a first plane (D) perpendicular to the screen (6) and passing through a light source (32) associated with the cavity (8), wherein the cavity (8) comprises a parabolic profile (37) in a second plane (E) perpendicular to the screen (6) and passing through a light source (32) associated with the cavity (8), The proximal end (16) forms a first terminal of the light box (4), the second terminal (22) of the light box (4) is located on a side of the light box opposite to the first terminal along the stacking axis (Y), and a ratio between a first dimension (18) associated with a wall (14) of the cavity (8) and a second dimension (19) associated with the light box is in a range from 40% to 85%, the first dimension (18) being measured parallel to the stacking axis (Y) between the proximal end (16) of the cavity and the distal end (17) of the cavity, and the second dimension (19) being an overall lateral dimension of the light box (4) measured parallel to the stacking axis (Y) between the proximal end (16) of the cavity and the second terminal (22).

2. The optical system (1, 2) according to claim 1, wherein: The light source is an RGB light source and / or an RGBW light source.

3. The optical system (1, 2) according to claim 1, wherein: The light box (4) comprises a dimension along a stacking axis (Y) which varies between a first longitudinal end (26) and a second longitudinal end (28).

4. The optical system (1, 2) according to claim 1, wherein: The inner surface (15) of the wall (14) is covered with a material that achieves both specular and diffuse reflection of the light beam.

5. The optical system (1, 2) according to claim 4, wherein: The inner surface (15) of the wall (14) comprises a plurality of diffusing microstructures (24).

6. The optical system (1, 2) according to any one of claims 1 to 5, wherein: The optical system (1, 2) comprises a control module, which is configured to give instructions for selectively activating the light source to achieve the display of dynamic and / or multi-color light signals.

7. A motor vehicle (100) comprising an interior lighting device (115) comprising an optical system (1, 2) according to any one of the preceding claims.

8. The motor vehicle (100) according to the preceding claim, wherein: The optical system (1, 2) is located at the height of a strip on a door (120) of the motor vehicle (100) and / or at the height of a strip on a panel (122) of the motor vehicle (100).

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