Optical module of luminous automotive vehicle system

Abstract

To provide an optical module (20) of a luminous automotive vehicle system.SOLUTION: An optical module of a luminous automotive vehicle system comprises: a light source (2); a primary optical system (4) comprising at least two optical members (5), in which primary optical system (4), each optical member is configured to form an image from the light source, and the image is shifted with respect to the image formed by each other optical member from the light source; and an optical projection system (7) configured to project onto the ground the image formed by each optical member of the primary optical system from the light source.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to the field of light-emitting motor vehicle systems. In particular, the present invention relates to an optical module for a light-emitting system of a motor vehicle. [Background technology]

[0002] In the field of lighting and light signalling for motor vehicles, it is known to perform, in addition to conventional functions, a function that allows the projection of logos or light patterns onto the ground in the near field of the vehicle. This type of function can be used in driver assistance situations to create markings on the ground that allow, for example, traffic lanes to be indicated. This type of function can also be used to augment conventional signalling functions in order to inform other road users of a change of course.

[0003] One known solution for projecting luminous patterns or logos onto the ground consists in introducing dark areas into the pixelated light beam emitted by the lighting system of the motor vehicle. The driver or road user thus sees the pattern or logo through the contrast between the dark and light areas. However, this solution requires that the light beam have a particularly high resolution, and therefore a particularly large number of light sources, which makes the lighting system expensive and complex.

[0004] Another known solution consists in projecting the light emitted by a light source through a mask with apertures whose contours correspond to the contours of the pattern or logo that it is desired to project onto the ground. This solution is much cheaper than the previous one, but is less efficient since a large part of the light is blocked or absorbed by the mask.

[0005] Another known solution consists in concentrating the light emitted by several light sources through light guides and projecting the images of the light exit surfaces of these light guides onto the ground through a projection optical system. Although this solution is satisfactory from the standpoint of efficiency and simplicity, it does not allow the creation of complex patterns on the ground without increasing the number of light sources and light guides. Summary of the Invention

[0006] Thus, there is a need for an efficient and simple optical module that can project luminous patterns or logos onto the ground, allowing complex patterns to be formed using a single light source.

[0007] The present invention is within this context and aims to meet this need.

[0008] To these ends, one subject of the invention is an optical module for a lighting system of a motor vehicle, comprising: a. a light source; b. a primary optical system comprising at least two optical elements, each optical element configured to form an image from the light source, the image being offset relative to images formed from the light source by each of the other optical elements; c. a projection optical system configured to project an image formed from the light source by each optical element of the primary optical system onto the ground; It is an optical module equipped with the above.

[0009] In the present invention, the light rays emitted by the light source are deflected by each optical element so as to form a separate image of the light source. This may be a matter of virtual or real images, which may essentially correspond to an enlarged image of the light-emitting surface of the light source, or may rather be a distorted image of this light-emitting surface. It should be noted that most or even all of the light rays emitted by the light source may thus be collected by each optical element to form each image. For example, the images may be adjacent and have a common boundary, or may be separate. Each image is then projected onto the ground by a projection optical system to obtain a complex pattern of contours with sufficient clarity on the ground.

[0010] The projection optical system preferably has a focal plane that passes substantially through the image formed from the light source by each optical element of the primary optical system.

[0011] In one embodiment of the invention, the projection optics is configured to project images formed by the optical elements of the primary optics onto the ground in the near field of the vehicle, where near field means a projection distance of less than 10 meters (particularly less than 5 meters) and / or an overall projection direction that forms an angle of at least 5° below horizontal (particularly at least 10° below horizontal). These images may thus contribute to the performance of functions indicating the route to be followed by the vehicle (particularly functions such as turn signals and reversing lights).

[0012] In the present invention, the light pattern formed by projecting a secondary image onto the ground using a projection optical system may form a logo, a pictogram, a geometric pattern, or a set of multiple logos, pictograms, or geometric patterns, or a combination thereof, for example a pictogram associated with one or more geometric patterns.

[0013] In one embodiment of the present invention, the optical elements are coupled to the same output optical element to form primary optical elements of the primary optical system, each optical element having a light entry surface arranged facing the light source and a bonding surface connecting the optical element to the output optical element, the primary optical element being an integral part. Where appropriate, the projection optical system is configured to project an image of each bonding surface of the optical elements onto the ground. In other words, each optical element is a primary optical element configured to form an image of the light source at its bonding surface with the output optical element.

[0014] Each optical element is preferably configured so that the image of its joint surface projected onto the ground by the projection optical system is entirely bounded by a fairly sharp edge. In the present invention, "the image projected onto the ground has a fairly sharp edge" means that the change in illuminance caused by this projection (between two points located on either side of the edge in a direction approximately perpendicular to the edge and spaced at least 1 cm apart) has a slope of 10 lux / cm or more (particularly at at least one location). For example, the projection optical system may have a focal plane that substantially passes through the joint surface of each optical element with the light-emitting optical element. For example, the focal plane may be a flat or curved surface located substantially within the joint plane between each joint surface and the light-emitting optical element.

[0015] For example, the light entrance surfaces of the optical elements may be formed by the same light entrance surface, with the latter light entrance surface being common to all the optical elements, and each optical element may extend from this common light entrance surface towards the light-emitting optical element in a direction separate from the other optical elements.

[0016] Advantageously, the optical elements are connected to the light-emitting optical element such that the mating surfaces of at least two adjacent optical elements with the light-emitting optical element are spaced apart from one another. This feature thus allows a gap to be created between the images of the mating surfaces of the two adjacent optical elements, with the edges of these images clearly defining this gap on the ground. All mating surfaces may have substantially the same shape, orientation, and / or dimensions, or alternatively, at least two mating surfaces may have distinct shapes, orientations, and / or dimensions.

[0017] Advantageously, each optical element comprises a primary light guide.

[0018] In another embodiment of the invention, the primary optical system comprises a primary optical element comprising at least one primary light guide coupled to an output optical element, the primary light guide having a light entrance surface arranged facing the light source and a bonding surface connecting the primary light guide to the output optical element, the primary optical element being a monolithic component, and the image formed by each optical element being an image of the bonding surface. In this embodiment, each optical element is a secondary optical element. It is conceivable that the optical elements together form a monolithic component, the secondary optical element. It is preferred that the primary optical element comprises a single primary light guide, such that each optical element mirrors the bonding surface of the primary light guide with the output optical element.

[0019] Advantageously, each optical element may be a lens (particularly a microlens) and have an optical axis that is distinct from the optical axes of each of the other lenses. Where appropriate, each lens may have an object focal plane that passes substantially through the interface of the primary light guide with the output optical element. If desired, the optical axes of the lenses may be parallel to each other and offset (e.g., vertically) from each other.

[0020] Preferably, the lenses may be configured such that the images of the interface are formed in the same plane upstream of the interface, and where appropriate the projection optics may have a focal plane that passes substantially through this plane.

[0021] Alternatively, each optical element may be a facet of the same reflector, the facet having a slope that is distinct from the slope of each of the other facets of the reflector.

[0022] In either embodiment, it is advantageous if the light entrance surface of the or each primary light guide is connected to the interface surface of the primary light guide by an envelope surface such that each point on the outline of the light entrance surface is connected by a straight line to a point on the outline of the interface surface. In other words, the light guide envelope surface is a developable surface. According to this feature, light emitted by the light source through the light entrance surface of the primary light guide propagates by total internal reflection from the wall of the light guide until it reaches the interface surface. The fact that the envelope surface is a developable surface makes it possible to form a pattern at the interface that is generally outlined with fairly sharp edges.

[0023] Advantageously, the entrance surface of the (particularly each) primary light guide is substantially rectangular. Where appropriate, the joining surface of the light guide has a shape substantially different from the shape of the entrance surface of the light guide. According to this feature, each primary light guide can be optimized at its joining surface to obtain a pattern of a predetermined shape corresponding to the shape of this joining surface. This pattern can be distinct for each primary light guide and can be projected onto the ground in the sharpest possible way by the projection optics. The joining surface can have a different number of edges than the entrance surface and / or edges of different dimensions than the edges of the entrance surface and / or angles between the edges that are different from those between the edges of the entrance surface. In particular, the shape of the joining surface can be distinct from any shape that can be obtained by a similarity transformation of the shape of the entrance surface. For example, the joining surface can be substantially triangular, trapezoidal, rhombus or pentagonal.

[0024] Advantageously, the light output optic has a smooth, substantially dome-shaped light output surface.

[0025] Preferably, the refractive index of each primary light guide and each output optical element is substantially the same. For example, each primary light guide and each output optical element are made from the same material, particularly the same polymer. By "same material," we mean that each primary light guide and each output optical element are made from a material derived from at least the same base polymer (e.g., polycarbonate (i.e., PC) or PMMA). However, these materials may have different fillers. Preferably, each primary light guide and each output optical element are produced in a single mold to form the primary optical element, so that the primary optical element can be an integrated part. Alternatively, one or more (or even all) of each primary light guide and each output optical element can be produced in separate molds and then assembled to form the primary optical element. If appropriate, the primary light guide produced in a separate mold from the output optical element can be adhesively bonded to the output optical element using an adhesive with a refractive index substantially the same as that of the primary light guide and the output optical element.

[0026] For example, the projection optical system may include at least one lens and / or at least one reflector, and / or a combination of at least one lens and at least one reflector. Preferably, the projection optical system may include a single projection lens whose focal plane substantially passes through the joint surface of the primary optical element and the output optical element. Alternatively, the projection optical system may include a substantially plane mirror (a substantially flat mirror body) and a projection lens. The former is configured to form virtual images of each joint surface on one side of the substantially plane mirror. The projection lens is located on the other side of the substantially plane mirror, and its focal plane substantially passes through these virtual images. This type of projection optical system allows for a substantial reduction in the bulk of the optical module.

[0027] The light source preferably comprises a light-emitting semiconductor chip, in particular a light-emitting diode.

[0028] Another subject of the invention is a lighting system for a motor vehicle, comprising an optical module according to the invention.

[0029] For example, the lighting system may comprise a lighting device such as a tail light of a motor vehicle and / or a front head light of a motor vehicle, and / or a lighting device arranged in a bumper of a motor vehicle and / or in a rear view mirror of a motor vehicle, and the optical module may be arranged in the lighting device.

[0030] The present invention will now be described, by way of example only and not by way of limitation of the scope of the invention, with reference to the accompanying drawings in which various figures are depicted. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic, partially depicting cross-sectional view of an optical module according to an embodiment of the present invention; [Figure 2] 2 is a schematic, partially depicting perspective view of a primary optical element in the module of FIG. 1; FIG. [Figure 3] 2 is a schematic, partially depicting view of a lighting system for a motor vehicle incorporating the optical module of FIG. 1, according to one embodiment of the present invention; [Figure 4] 10 is a schematic, partially depicting cross-sectional view of an optical module according to another embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0032] In the following description, elements that are identical in structure or function and that appear in more than one figure are designated by the same reference numeral unless otherwise indicated. FIG. 1 depicts an optical module 1 for a lighting system of a motor vehicle according to a first embodiment of the invention.

[0033] The optical module 1 comprises a single light emitting diode 2 mounted on a printed circuit board 3 .

[0034] The optical module 1 comprises a primary optics 4 in the form of a primary optical element 4 arranged downstream of the light emitting diode 2. This primary optical element 4 will be explained with reference to Figure 2, which shows this element 4 in a rear perspective view.

[0035] The primary optical element 4 comprises a plurality of optical elements 5 and a light output optical element 6 to which the optical elements 5 are connected. In the example illustrated, each optical element 5 is in the form of a primary light guide.

[0036] The primary light guides 5 have a common light entrance surface 51, and the LEDs 2 are arranged facing this light entrance surface 51. Thus, light emitted by the LEDs 2 enters each primary light guide 5 through this light entrance surface 51.

[0037] Each primary light guide 5 is connected to a light output optic 6 by a mating surface 52. The mating surface 52 is located at the upstream wall 61 of the light output optic 6, opposite the light entrance surface 51. The primary light guides 5 are placed one above the other such that the mating surfaces 52 are spaced apart.

[0038] Each light guide 5 thus extends from a common light entrance surface 51 to its respective interface surface 52. Therefore, the primary light guides 5 share a common envelope surface until they separate and extend to their respective light exit surfaces at their respective envelope surfaces 53. These envelope surfaces 53 are developable so that each point on the outline of the light entrance surface 51 is connected (through the envelope surface 53) by a straight line to a point on the outline of the interface surface 52. Thus, light emitted by the LEDs 2 positioned facing the light entrance surface 51 is coupled into each primary light guide 5 and propagates through successive total internal reflections against the envelope surface 53 until it reaches the interface surface 52. The light is separated from the primary light guides 5 through the interface surface 52 and enters the light output optical element 6. The interface surface 52 thus forms the virtual light exit surface of the primary light guide 5.

[0039] The interface surfaces 52 of the primary light guides 5 may be distinct from one another and from the light entrance surface 51. The interface surfaces 52 of the primary light guides 5 thus define, by their contours, a pattern of a predetermined shape that is specific to that light guide 5. The envelope surface 53 of each primary light guide 5 thus makes it possible to utilize all of the light emitted by the LEDs 2 through the light entrance surface 51 in a manner that results in an overall contoured pattern with fairly sharp edges at the interface surface 52. Similarly, the envelope surface 53 makes it possible to obtain a uniform light distribution within this pattern at the interface surface 52.

[0040] In the example described, the interface 52 of the lower light guide has a triangular shape, while the interface 52 of the central and upper light guides has a trapezoidal shape, with the dimensions of the interface 52 of the upper guide being smaller than the dimensions of the interface 52 of the central guide.

[0041] As explained above, the primary light guides 5 are arranged such that there is a gap between two adjacent joint surfaces 52. In other words, the primary light guides 5 thus enable multiple images from the LEDs 2 to be formed at the joint surfaces 52. These images are thus vertically offset from one another.

[0042] The primary optical element 4 is a one-piece component, with the primary light guides 5 and the output optical elements 6 being made from the same material, namely polycarbonate, or PC. In the example being described, the primary optical element 4 is a component created in a single mold. In other words, the refractive index of each primary light guide 5 and the output optical elements 6 is the same, and there is no refractive interface at each bonding surface 52. This is so that light entering the output optical elements 6 from each primary light guide 5 is not deflected at each bonding surface 52.

[0043] The light output optical element 6 has a light output surface 62 in the shape of a smooth dome on the side opposite the upstream side 61. In particular, the light output surface 62 may be partially spherical, so that the light output optical element 6 has the shape of a partially truncated sphere. The light output surface 62 is particularly centered on the bonding surface 52 of the central light guide 5. As a result, light coming from each bonding surface 52 is not substantially deflected while exiting the primary optical element 4 through the light output surface 62. The light output optical element 6 thus forms a support for mounting each primary light guide 5, and elements for fixing the primary optical element 4 can be arranged on the light output optical element 6.

[0044] The optical module 1 comprises a projection optical system 7. In the example of Figure 1, the projection optical system 7 is a projection lens having a focal plane 71 that passes substantially through the joint surface 52 of each primary light guide 5.

[0045] The projection lens 7 is thus configured to project an image of each interface 52 onto the ground (in the near field). Because the pattern formed on each interface 52 is outlined by generally sharp edges (as an effect of each primary light guide 5), and because the focal plane 71 passes through these interfaces 52, the images projected onto the ground are themselves outlined by generally sharp edges (after inversion by the projection lens 7) corresponding to the edges of these interfaces 52.

[0046] FIG. 3 illustrates a lighting system 10 for a motor vehicle according to an exemplary embodiment of the present invention.

[0047] The lighting system 10 comprises a front headlight 11 in which the optical module 1 of FIG. 1 is arranged.

[0048] The lighting system 10 comprises a control unit (not shown) which receives instructions from the motor vehicle's computer to perform lighting functions and controls the LEDs 2 of the optical module 1 in response to these instructions.

[0049] Upon receiving a command to perform a sequential turn signal function (e.g., generated by a computer when the motor vehicle wants to change lanes), the control unit turns on LED 2, causing optical module 1 to project images 1a, 1b, and 1c of interface surface 52 of each primary light guide 5 onto the ground (in the near field of the vehicle). It should be understood that optical module 1 thus performs a turn signal function that may complement the turn signal function performed by the vehicle's taillights. Because images 1a, 1b, and 1c are projected onto the ground (in the near field of the vehicle), they can be easily perceived by road users driving on the right side of the motor vehicle. In particular, the images replicated by each primary light guide 5 from LED 2 are shown in FIG. 3.

[0050] FIG. 4 depicts an optical module 20 of a lighting system for a motor vehicle according to a second embodiment of the invention.

[0051] In this example, the optical module 20 comprises a single LED 2 and a primary optical element arranged downstream of the light emitting diode 2, as in the example of Figure 1. However, unlike Figure 1, the primary optical element comprises a single primary light guide 5. The function of the primary light guide 5 is simply to form a single image from the LED 2 at the junction surface 52. The primary light guide 5 is thus involved in forming the pattern that will be projected onto the ground, but not in replicating this pattern.

[0052] For this purpose, the primary optical system 4 of the optical module 20 comprises a number of optical elements 8 arranged between the primary optical element 4 and the projection optical system 7. Each optical element 8 is thus a secondary optical element, formed by a microlens 8 in the example of Figure 4.

[0053] Each microlens 8 has a focal plane 81 located downstream of the cemented surface 52 and an optical axis 82. The optical axes 82 are parallel to each other but offset with respect to each other. Each microlens 8 is thus configured to form an image of the cemented surface 52 in a given plane 83 (through the focal plane of the projection optics 7) located upstream of the primary optical element 4. The images of the cemented surfaces 52 are vertically offset from each other.

[0054] Thus, projection of these images of the cemented surface 52 by the projection optics 7 makes it possible to project the same pattern onto the ground in a replicating manner.

[0055] The above description clearly illustrates how the present invention achieves the objective it has set for itself: to provide an efficient and simple optical module that allows complex patterns to be projected onto a surface from a single light source, the optical module comprising optical elements configured to replicate the image formed by the light source.

[0056] In any case, the invention is not limited to the embodiments specifically described in this document, but in particular extends to any equivalent means and any technically functional combination of these means. In particular, it is possible to imagine light sources of other types than those described, in particular light sources capable of emitting light of a color other than white or of a controllable color. It is also possible to imagine shapes for the joining surfaces other than those described. It is also possible to imagine types of optical elements other than light guides or microlenses, in particular collimators, lenses or microlenses, multifaceted reflectors, or combinations of different types of primary optical elements. It is also possible to imagine light-emitting functions other than those described, in particular other functions for indicating changes in the direction of a motor vehicle (for example, reverse or lane change indicators), driver assistance functions, or other vehicle-to-vehicle communication functions.

Claims

1. An optical module (1, 20) for a lighting system (10) of a motor vehicle, comprising: a. a light source (2); b. a primary optical system (4) comprising at least two optical elements (5, 8), each configured to form an image from the light source, the image being offset relative to images formed from the light source by each of the other optical elements; c) a projection optical system (7) configured to project an image formed from the light source by each optical element of the primary optical system onto the ground; An optical module (1, 20) comprising:

2. The optical module (1, 20) according to the preceding claim, wherein the projection optical system (7) has a focal plane (71) that substantially passes through an image formed from the light source (2) by each optical element (5, 8) of the primary optical system (4).

3. 10. The optical module (1) according to claim 9, wherein the optical elements (5) are connected to the same light-output optical element (6) to form primary optical elements of the primary optical system (4), each optical element having a light-input surface (51) arranged facing the light source and a bonding surface (52) connecting the optical element to the light-output optical element, the primary optical elements being an integral part, and the projection optical system (7) being configured to project an image of each of the bonding surfaces of the optical elements onto the ground.

4. An optical module (1) according to the preceding claims, wherein each optical element (5) comprises a primary light guide.

5. 3. An optical module (20) according to claim 1 or claim 2, wherein the primary optical system (4) comprises a primary optical element comprising at least one primary light guide (5) coupled to a light output optical element (6), the primary light guide having a light entrance surface (51) arranged facing the light source (2) and a bonding surface (52) connecting the primary light guide to the light output optical element, the primary optical element being an integral part, and the image formed by each optical element (8) being an image of the bonding surface.

6. An optical module (20) according to the preceding claims, wherein each optical element (8) is a lens having an optical axis (82) distinct from the optical axes of each of the other lenses.

7. 10. An optical module (20) according to claim 9, wherein the lens (8) is configured such that images of the joining surface (52) are formed in the same plane (83) upstream of the joining surface.

8. 6. An optical module (20) according to claim 5, wherein each optical element (8) is a facet of the same reflector, the facet having a tilt that is distinct from the tilt of each of the other facets of the reflector.

9. 9. An optical module (1, 20) according to any one of claims 4 to 8, wherein the entrance light surface (51) of each primary light guide (5) is connected to the joint surface (52) of the primary light guide by an envelope surface (53) such that each point on the contour of the entrance light surface is connected by a straight line to a point on the contour of the joint surface.

10. 10. The optical module (1, 20) according to any one of claims 4 to 9, wherein the light-emitting optical element (6) has a smooth, substantially dome-shaped light-emitting surface (62).

11. A lighting system (10) for a motor vehicle, comprising an optical module (1, 20) according to any one of the preceding claims.

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