Optical element made of injected plastic

Abstract

The invention relates to an optical element (2) made of injected plastic, comprising a plurality of light guides (7) extending alongside one another, the optical element further comprising a body (6) from which the light guides extend, the body comprising an injection point (17) through which plastic has been injected in order to form the optical element, the body (6) comprising a first portion (18) positioned between the injection point and a first light guide (7A), the body (6) comprising a second portion (19) positioned between the injection point and a second light guide (7B), the second light guide (7B) being further away from the injection point than the first light guide (7A), a thickness (e1) of the first portion (18) being strictly less than a thickness (e2) of the second portion (19).

Description

[0001] DESCRIPTION

[0002] TITLE: OPTICAL ELEMENT MADE OF INJECTED PLASTIC MATERIAL

[0003] Technical field of the invention

[0004] The invention relates to an optical element made of plastic material injected by molding. The invention also relates to a light module comprising such an optical element. The invention further relates to a method for manufacturing such an optical element. The invention finally relates to an injection mold configured to manufacture such an optical element.

[0005] State of the prior art

[0006] Lighting devices for motor vehicles are known, comprising a transparent optical element cooperating with a set of light sources. The optical element comprises a set of light guides, each light guide cooperating with a separate light source. Each light guide is intended to project a portion of a light beam. When all the light sources are switched on, the light module projects a wide light beam composed of the different parts of the light beam. This wide light beam can be modulated by individually controlling the switching on of each light source. This makes it possible to achieve various useful lighting functions in a motor vehicle, such as, for example, an anti-glare function.

[0007] Optical elements made of injected plastic, particularly silicone, are thus known. Document JP2021044119A discloses an example of such an optical element.

[0008] Although it has a very complex shape, the optical element must be manufactured with great precision so that the different parts of the light beam it produces are adjacent to each other without overlapping or poorly lit areas.

[0009] The optical elements known from the state of the art have insufficient optical quality. In particular, it is observed that the parts of the light beam coming from the different light guides are poorly positioned and / or produce light that is too diffuse.

[0010] Furthermore, in order to achieve satisfactory compactness and optical performance, each light guide of the optical element is generally positioned at a short distance from the adjacent light guides. Therefore, the injection mold required to manufacture such an optical element comprises thin blades, each interposed between two adjacent light guides. On the one hand, such an optical element is difficult to demold. On the other hand, it is observed that the blades of the mold tend to break or deform, which disrupts the production of the optical elements.

[0011] Presentation of the invention

[0012] The aim of the invention is to provide an optical element which at least partially overcomes the above drawbacks and improves the optical elements known from the prior art.

[0013] More specifically, a first object of the invention is an optical element which is easy to manufacture and whose light guides have optimal optical quality and allow the generation of very well-positioned parts of the light beam.

[0014] A second object of the invention is a method of manufacturing such an optical element which is particularly efficient and effective. Summary of the invention

[0015] The invention relates to an optical element made of injected plastic material comprising a plurality of light guides extending alongside each other, the optical element further comprising a body from which said light guides extend, the body comprising an injection point through which plastic material has been injected to form the optical element, the body comprising a first portion interposed between said injection point and at least one first light guide, the body comprising a second portion distinct from the first portion and interposed between said injection point and at least one second light guide, the at least one second light guide being further from said injection point than the at least one first light guide,a thickness of the first portion being strictly less than a thickness of the second portion so as to simultaneously fill the at least one first light guide and the at least one second light guide during the injection of the optical element into an injection mold.,

[0016] By "interposed" we mean that said portion is positioned on the path of a front of molten plastic material, during the manufacture of the optical element by injection, upstream of the respective light guide.

[0017] The light guides can extend substantially parallel to the same optical axis.

[0018] Said first portion and said second portion of the body may extend in a plane substantially perpendicular to the optical axis.

[0019] The light guides of the plurality of light guides may be distributed along a second axis, substantially perpendicular to the optical axis. Each light guide of the plurality of light guides may comprise a cross-section to the direction in which it extends which has a substantially polygonal shape, in particular a rectangular shape.

[0020] Each light guide of the plurality of light guides may comprise a first end connected to said body and a second free end, a distance separating the second end of two adjacent light guides being less than or equal to 4 mm, and / or a length of each light guide measured between its first end and its second end being greater than or equal to 7 mm.

[0021] The plastic material can be a transparent thermoplastic polymer, notably polymethyl methacrylate (PMMA) or polyamide (PA) or polycarbonate (PC). A thermoplastic polymer is heated to make it fluid. It can then be injected into a mold. Then, it hardens upon cooling, which allows it to retain the shape of the mold impression. Conversely, a thermoset or an elastomer such as silicone is heated to generate a crosslinking reaction that freezes the shape of the part. Optionally, the latter can have elastic properties, that is, it can be stretched, up to a plastic deformation threshold or a breaking threshold, then return to its initial shape when the stretch is released. This is, for example, the case with silicone. The use of a thermoplastic polymer has the advantage of simplifying the molding of the part.Furthermore, since silicone is flexible, it is necessary to associate it with a rigid frame to hold a part made from this material, which is not the case for a part made from thermoplastic polymer. The invention also relates to a light module comprising an optical element as defined in the present application and a set of light sources, a separate light source being positioned opposite at least a portion of the light guides, in particular opposite each light guide of the optical element. The light sources are arranged such that when they are lit, the light they emit enters at least partly into the respective associated light guide.

[0022] The optical element has an exit face, through which at least part of the light which has entered the light guides exits.

[0023] The light module has an optical axis, corresponding to the general direction of the light after it has exited the optical element through the exit surface.

[0024] The invention also relates to a lighting device of a motor vehicle, the lighting device comprising a housing and a glass for closing the housing, the housing and the closing glass forming an internal volume, the lighting device also comprising a light module according to the invention arranged inside said volume, such that when the light sources of the light module are switched on, the light which they emit and which emerges from the optical element passes at least partly through the closing glass.

[0025] The light module may in particular be a lighting and / or signaling device, or a vehicle interior lighting device.

[0026] The invention also relates to a method of manufacturing by injection of plastic material an optical element according to the invention. The invention also relates to a method of manufacturing by injection of plastic material an optical element comprising a plurality of light guides extending next to each other, the optical element further comprising a body from which said light guides extend, the body comprising an injection point, the body comprising a first portion interposed between said injection point and at least one first light guide, the body comprising a second portion distinct from the first portion and interposed between said injection point and at least one second light guide, the at least one second light guide being further from said injection point than the at least one first light guide, the manufacturing method comprising:

[0027] - the injection of molten plastic material through the injection point, then

[0028] - simultaneously filling the at least one first light guide and the at least one second light guide with molten plastic material.

[0029] The invention also relates to an injection mold configured to manufacture an optical element according to the invention.

[0030] Presentation of figures

[0031] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of a particular embodiment made without limitation in relation to the attached figures among which:

[0032] Figure 1 is a sectional view of a light module according to one embodiment of the invention.

[0033] Figure 2 is a front perspective view of an optical element according to one embodiment of the invention.

[0034] Figure 3 is a sectional view of an optical element according to an embodiment of the invention. Figure 4 is a sectional view, during its injection, of an optical element according to an embodiment of the invention.

[0035] Figure 5 is a sectional view, during its injection, of an optical element according to the state of the art.

[0036] Detailed description

[0037] Figure 1 illustrates a light module 1 according to one embodiment of the invention. The light module 1 comprises an optical element 2 and a set of light sources 3. In particular, the light sources 3 may be light-emitting diodes. The light sources 3 are arranged on the surface of the same printed circuit board 4 and are electrically connected to this printed circuit board. The optical element 2 is fixed, in particular by means of two fixing screws 5 to the printed circuit board 4.

[0038] The light module 1 may be intended to be embedded in a motor vehicle. It may in particular be intended to perform a lighting function and / or a function for signaling the position of the vehicle. Each light source 3 may be controlled individually so as to modify the light beam produced by the light module 1. For this purpose, the light module 1 may be electrically connected to an electronic control unit controlling the switching on or off of each light source 3. The light module may thus be controlled so as to perform, for example, an anti-dazzle function for other road users.

[0039] An embodiment of the optical element 2 is illustrated in Figure 2. The optical element 2 is made of a transparent material and is intended to guide the light rays coming from the light sources 3. The optical element 2 comprises a body 6 and a plurality of light guides 7 extending from the body 6. Each light guide 7 comprises a first end 8 connected to the body 6 and a second free end 9. Each light guide is intended to produce a light beam, at the output of the light guide in question, centered on an optical axis. The optical axis of a light guide may correspond to the axis along which the light guide extends and is oriented in the direction of propagation of the light rays which pass through the light guide. The optical axes of the different light guides may be substantially parallel to each other.By "substantially parallel" is meant that the optical axes of two adjacent light guides may form an angle less than or equal to 1°, preferably less than or equal to 0.5°. Alternatively, the angle formed between adjacent light guides could reach larger values.

[0040] A separate light source 3 is positioned opposite each light guide 7 of the optical element 2. In particular, each light source is positioned opposite a free end 9 of a light guide 7. There are therefore as many light guides 7 as there are light sources 3. According to an alternative embodiment, the light module could comprise a number of light sources different from the number of light guides. In particular, the light module could comprise several light sources associated with the same light guide. The light emitted by each light source 3 enters the light guide 7 associated with it. It exits the optical element 2 via an exit face 21. The light module 1 has an optical axis X, corresponding to the general direction of the light after it has exited the optical element 2 via the exit surface 21.In the event that the different light guides form a small angle between them as explained previously, the optical axis X of the light module could be defined as the optical axis of a central light guide among the set of light guides. According to the embodiment shown in Figure 2, the optical element comprises 18 light guides. Alternatively, the number of light guides 7 could be different, for example at least 4 light guides, preferably at least 10 light guides, or even at least 20 light guides. As a note, the embodiment of Figure 3 presents 19 light guides 7 compared to 18 light guides for the embodiment of Figure 2.

[0041] The various light guides are arranged so that the light beams they produce are adjacent to each other, preferably without any unlit area or major overlap of two adjacent light beams. Taking into account a certain manufacturing dispersion of the light modules, it is nevertheless possible to provide or tolerate a minor overlap of two adjacent light beams to avoid the appearance of unlit areas. In particular, an overall illumination area of ​​the light module can thus be subdivided into as many parts as the optical element comprises light guides 7.

[0042] As illustrated in Figure 1, the body 6 further comprises an output face 21, in particular of convex shape, and intended to orient the light rays R coming from each light guide 7. The light beam coming from the light module is thus a light beam comprising distinct portions associated with each light guide 7. Each of the portions of the light beam is intended to illuminate a distinct zone of the environment of the vehicle.

[0043] The light guides 7 extend alongside each other. The free ends 9 of the light guides 7 are positioned in the same plane, parallel to the plane in which the printed circuit board 4 extends. In particular, the free ends 9 are positioned on a second axis Y, perpendicular to the optical axis X. Thus the optical element 2 has roughly the shape of a comb. A third axis Z can be defined, perpendicular to the optical axis X and to the second axis Y. The axes X, Y and Z thus form an orthogonal reference frame.

[0044] The convex shape of the output face 21 mentioned above is obtained when placed in a plane parallel to the X and Y axes. The output face 21 has a profile which is further forward in the direction of the optical axis X at its center relative to its ends.

[0045] Furthermore, the output face 21 may also have a convex shape in a plane parallel to the X and Z axes. This makes it possible to extend the angular extension of the light beam in the Z direction.

[0046] Alternatively, the output face 21 has a cylindrical shape. It then retains its convexity in the plane parallel to the X and Z axes, but it has a rectilinear section in the plane parallel to the X and Y axes. In this case, the juxtaposition of portions of the light beam is carried out by an additional projection optic (not shown), which may for example be a lens or a reflector.

[0047] The distance D1 separating the free ends 9 of two adjacent light guides 7 may be substantially constant, i.e. vary by less than 20% between two adjacent light guides. The distance D1 separating the free end 9 of two adjacent light guides 7 is preferably less than or equal to 4 mm, or even less than or equal to 3 mm. The optical element is thus particularly compact and can be easily integrated into a light module of a motor vehicle.

[0048] The light guides 7 may have a length L1 that varies in the direction in which they extend, i.e. along the optical axis X. As can be seen in FIGS. 1 and 2, the light guides 7 positioned towards the center of the optical element 2 may be shorter than the light guides positioned towards the edges of the optical element. Thus, the first ends 8 of each light guide 7 are advantageously positioned in a focal surface of the output face 21 of the optical element. Preferably, the light guides 7 comprise a length L1 greater than or equal to 7 mm, for example between 7 mm and 17 mm inclusive. The length L1 of each light guide 7 may be measured between its first end 8 and its free end 9.In the case where the output face 21 has a cylindrical shape, the first ends 8 of each light guide 7 are advantageously positioned in a focal surface of the additional projection optics. More precisely, the images of the first ends 8 of each light guide 7 by the output face 21 are positioned in a focal surface of the additional projection optics. This positioning in the focal surface of the output face 21 of the optical element, or of the additional projection optics, respectively, makes it possible to improve the quality of the light beam.

[0049] In an alternative embodiment, the output face 21 has a convex shape in a plane parallel to the X and Y axes as described above, without however this convexity alone allowing the correct positioning of the portions of the light beam to be fully ensured. An additional projection optic is then also used to obtain the juxtaposition of the portions of the light beam. Here again, the images of the first ends 8 of each light guide 7 by the output face 21 are advantageously positioned in a focal surface of the additional projection optic. The output face 21 may also have a convex shape in a plane parallel to the X and Z axes. Alternatively, the light guides 7 may all have an identical length L1 in the direction in which they extend, i.e. along the optical axis X.This configuration makes it possible to optimize the balancing of the pressures exerted on the metal blades of the mold present between adjacent light guides, during the manufacture of the optical element, as will be seen later.

[0050] The body 6 of the optical element 2 comprises a curved portion 10, projecting in the opposite direction from the optical axis X, and on which the light guides 7 are installed. The cross-section to the direction in which each light guide 7 extends may comprise a substantially polygonal shape, in particular a rectangular shape. In particular, each light guide may comprise a truncated pyramid shape. The cross-section of each light guide may be slightly decreasing as one approaches the free end 9. Alternatively, the light guides 7 could comprise a different shape, for example a cylindrical, conical or prismatic shape. The light guides 7 are not hollow but, on the contrary, are filled with material.

[0051] Each light guide comprises at least one flat face 11 extending opposite a flat face of an adjacent light guide. In particular due to the truncated pyramid shape of the light guides, the two opposite flat faces may be slightly inclined relative to each other. The adjacent light guides are separated from each other by an air gap 12. The air gaps 12 may be narrower at the first end 8 of the light guides 7 than at their free end 9. At their first end 8, the adjacent light guides may be connected to each other by a connection zone having a very small radius, for example less than or equal to one millimeter. The body 6 comprises a central portion 13 extending generally in a plane perpendicular to the optical axis X. The central portion 13 may in particular extend on either side of the second axis Y.Referring to Figure 2, the central portion 13 comprises a portion extending above the curved portion 10 and another portion extending below the curved portion 10. As a note, the orientation of the optical element 2 in the position of use can be any. Thus the terms "above" and "below" relate only to the orientation shown in the figures.

[0052] The curved part 10 is connected to the central part 13 and extends over the entire width of the latter along the second axis Y. The central part 13 is extended by two fins 14 intended to position and fix the optical element 2 on the printed circuit board 4. The two fins 14 frame the light guides 7. The fins 14 comprise in particular fixing holes 15 cooperating with the fixing screws 5 and centering holes 16. As a note, the embodiment of Figure 3 has fins 14 comprising fixing holes and centering pins different from the fixing holes and centering holes of the embodiment of Figure 2.

[0053] The optical element 2 may comprise a plane of symmetry PS parallel to the optical axis X and to the third axis Z.

[0054] The optical element 2 is made of injected plastic material, that is to say it has been obtained by a process of injecting molten plastic material into an injection mold. Such a process gives the single-piece element a homogeneous monolithic structure as well as very high dimensional accuracy. In addition, such a manufacturing method is particularly economical and reproducible. The body 6 comprises an injection point 17 through which plastic material has been injected to form the optical element 2. Thus, in the vicinity of the injection point is the material entry zone of the optical element 2. This zone is the one that was first filled with the plastic material during the manufacturing process of said optical element. The injection point 17 may in particular be located substantially on the plane of symmetry PS of the optical element. The injection point 17 may also be located at an edge of the body 6.The injection point is thus arranged so that molten plastic material first fills at least part of the body 6 before filling the light guides 7.

[0055] The injection point 17 is not strictly punctual in the mathematical sense of the term. The injection point 17 is in fact a small surface of the optical element through which the molten plastic material is injected into a mold during its manufacture. In other words, the injection point 17 corresponds to the surface of the optical element positioned opposite an outlet of the molten plastic material injection nozzle, when the optical element is in its manufacturing mold. The injection point 17 can thus have a circular or square shape, but also rectangular, or that of a slot. The injection point 17 can in particular take the form of a spike or a sheet, visible to the naked eye. Preferably, the injection point 17 is positioned outside the path of the light rays emitted by the light sources 3 and passing through the optical element when the light module is operating.

[0056] Preferably, the optical element 2 is obtained by injecting molten plastic material through a single injection point so as to obtain an optical element free of air bubbles and / or weld lines. The optical element can also be obtained by a bi-injection process during which a core is injected during a first injection, the core then being overmolded during a second injection. Such a process makes it possible to better control the cooling of the injected part and to improve the production cycle time. The core is then designed so that its surfaces extend into areas which do not degrade the quality of the light beams transmitted by the optical element. In particular, the light guides 7 would preferably be formed during the second injection. Alternatively, the optical element 2 could also be obtained by a simple injection process in which the entire volume of the optical element is injected at once.

[0057] Among the light guides 7, a first light guide 7A positioned closest to the injection point 17 and a second light guide 7B positioned furthest from the injection point, in comparison to each other, can be identified. The distance separating a light guide from the injection point 17 can be defined as the distance traveled by the molten plastic material when it flows from the injection point 17 to the first end 8 of the light guide or to the free end 9 of the light guide. Given the position of the injection point in a middle zone of the optical element 2, the first light guide 7A is the most central light guide in the row of light guides 7, and the second light guide 7B is a light guide positioned at one end of the row of light guides 7.The guides positioned between the first light guide 7A and the second light guide 7B are increasingly distant from the injection point 17 as one moves from the first light guide 7A towards the second light guide 7B.

[0058] The body 6 comprises a first portion 18 interposed between the injection point 17 and the first light guide 7A, and a second portion 19, distinct from the first portion 18, interposed between the injection point 17 and the second light guide 7B. As will be described later, "interposed" means that the first portion 18, respectively the second portion 19, is positioned on the path of a front of molten plastic material, during the manufacture of the optical element by injection, upstream of the first light guide 7A, respectively upstream of the second light guide 7B. In other words, the molten plastic material intended to form the first light guide 7A passes inside the mold first through said first portion 18. Similarly, the second portion 19 is positioned on the path of a front of molten plastic material upstream of the second light guide 7B.In other words, the molten plastic material intended to form the second light guide 7B passes inside the mold first through said second portion 19. More precisely, the first light guide 7A is filled with plastic material whose front passes through the first portion 18 but not through the second portion 19, and the second light guide 7B is filled with plastic material whose front passes through the second portion 19 but not through the first portion 18. The portions 18 and 19 are notably formed in the central portion 13 of the body. According to the invention, a thickness e1 of the first portion 18 is strictly less than a thickness e2 of the second portion 19. The thickness of a portion 18 or 19 designates the dimension of this portion perpendicular to the plane in which the central portion 13 extends, that is to say the dimension parallel to the optical axis X. This difference in thickness is notably well illustrated in FIG. 3.The thickness e1 may for example comprise a thickness less than or equal to 80% of the thickness e2, or even less than or equal to 70% of the thickness e2, or even less than or equal to 50% of the thickness e2. The first portion 18 and the second portion 19 are advantageously arranged in zones of the optical element 2 which are not intended to be crossed by the light emitted by the light sources 3. According to one embodiment, this variation in thickness may be obtained by thinning the first portion 18 relative to the thickness of the remainder of the central portion 13 of the body 6. According to another embodiment, this variation in thickness may be obtained by thickening the second portion 19 relative to the thickness of the remainder of the central portion 13 of the body 6.According to yet another embodiment, and as illustrated in FIG. 3, this variation in thickness can be obtained by thinning the first portion 18 and thickening the second portion 19 relative to the thickness of the remainder of the central part 13 of the body 6.

[0059] The thinning of the first portion 18 can be obtained by providing a depression on the rear face of the central part 13, that is to say the face of the central part from which the light guides project. Alternatively, the thinning of the first portion 18 could be obtained by providing a depression on the front face of the central part 13, opposite the rear face, or even by providing a depression on the rear and front faces. Similarly, the thickening of the second portion 19 can be obtained by providing an excess thickness of material on the rear face and / or on the front face of the central part 13.

[0060] The first portion 18 may extend between two pillars 20 extending parallel to the third axis Z. The two pillars 20 may in particular belong to the core of the optical element 2 in the event that the optical element is manufactured by a bi-injection process. As can be seen in FIG. 2, the first portion 18 may comprise a generally rectangular shape. Alternatively, any other shape could be envisaged, for example more generally any polygonal shape such as a triangular or trapezoidal shape. The vertices of this shape may possibly be rounded. Thus, the first portion may also comprise an ellipsoidal shape, or even a circular shape. More generally, the first portion 18 may adopt any geometric shape making it possible to balance the propagation of a front of molten plastic material as will now be explained.

[0061] The difference in thickness between the first portion 18 and the second portion 19 makes it possible to simultaneously fill the first light guide 7A and the second light guide 7B when injecting the optical element into an injection mold. Indeed, a lower thickness e1 forms a section restriction which tends to slow down the propagation of the molten plastic front during the injection process. On the contrary, a greater thickness e2 facilitates the propagation of the molten plastic front during the injection process. This compensates for the effect caused by variable distances between the injection point and each light guide. It is thus possible to design the central part 13 of the body 6 so that the molten plastic front reaches each of the light guides simultaneously.By "simultaneously", we understand that there may remain gaps in the filling of each light guide but that these gaps are significantly reduced compared to the same optical element which would be devoid of artifice to balance the propagation of the front of molten plastic material.

[0062] Figures 4 and 5 clearly illustrate the benefit provided by the invention. These figures correspond to a partial filling of the optical element 2 during its injection. The part filled by the plastic material is represented by the points, and the material front, in the area of ​​the light guides 7, by the dotted curve. Figure 4 is a simulation of injection of an optical element according to the invention. It can be seen that the front F1 of molten plastic material is substantially perpendicular to the optical axis X. The different light guides 7 are therefore filled substantially simultaneously. On the contrary, Figure 5 is a simulation of injection of the same optical element but without variation in the thickness of the central part 13 of the body 6.It can be seen that the front F2 of molten plastic material has an arc shape: as the front of molten plastic material has a generally uniform speed in all directions, the light guides 7 furthest from the injection point 17 are filled after the light guides closest to the injection point.

[0063] Thanks to the invention, since the light guides 7 are filled substantially simultaneously during the injection process, the pressures exerted on the different walls of the injection mold are balanced. In particular, the injection mold, which comprises a shape complementary to that of the optical element 2, comprises relatively thin metal blades extending between the light guides 7. When the pressures exerted by the molten plastic material on the metal blades of the mold are unbalanced, the latter can twist or even break. When these blades twist, this induces geometric defects on the light guides 7 and therefore a lack of precision of the light beams coming from these optical guides. Thus, the invention therefore makes it possible to improve the optical precision of the optical element 2. The invention also makes it possible to preserve the injection mold and therefore to simplify the manufacture of the optical element 2.The invention also makes it possible to increase the holding pressure during injection of the optical element. This makes it possible to consider the use of a wider range of plastic materials.

[0064] One example is an optical element 2 made of a transparent thermoplastic polymer, such as polymethyl methacrylate (PMMA), polyamide (PA), or polycarbonate (PC). A thermoplastic polymer is more rigid than the silicone previously used for this type of optical element. The use of a thermoplastic polymer allows for longer light guides and does not require the use of additional structural parts to support the optical element.

[0065] To manufacture a light module 1, the optical element 2 can first be injected into an injection mold. Thanks to the invention, the different light guides are filled simultaneously or almost simultaneously during this injection process, which makes it possible to preserve the injection mold while achieving optimal optical quality of the optical element 2. The demolding axis of the optical element can be substantially parallel to the optical axis X. Since the light guides 7 are not deformed, the demolding of the optical element 2 is also facilitated. Then, and optionally, a sprue comprising the injection point 17 can be cut. In certain cases, the injection point 17 may therefore no longer be present, or be present in the form of a vestige, on the part which is integrated into the optical device. However, the material entry zone of the optical element 2 always remains visible and identifiable.Thus, within the framework of the invention, said material entry zone, that is to say the zone of the optical element 2 through which the material entered during injection, is assimilated to the injection point 17, when the latter is no longer present on said optical element 2. Then, the optical element 2 can be assembled on a printed circuit board 4 comprising light sources 3, in particular by means of the fixing screws 5. The single-piece nature of the optical element 2 allows very good positioning of the light guides relative to the light sources 3.

Claims

CLAIMS 1. An optical element (2) made of injected plastic material comprising a plurality of light guides (7) extending alongside one another, the optical element further comprising a body (6) from which said light guides extend, the body comprising an injection point (17) through which plastic material has been injected to form the optical element, the body (6) comprising a first portion (18) interposed between said injection point and at least one first light guide (7A), the body (6) comprising a second portion (19) distinct from the first portion (18) and interposed between said injection point and at least one second light guide (7B), the at least one second light guide (7B) being further from said injection point than the at least one first light guide (7A),a thickness (e1) of the first portion (18) being strictly less than a thickness (e2) of the second portion (19) so as to simultaneously fill the at least one first light guide and the at least one second light guide during the injection of the optical element (2) into an injection mold., 2. Optical element (2) according to the preceding claim, characterized in that the light guides (7) extend substantially parallel to the same optical axis (X).

3. Optical element (2) according to the preceding claim, characterized in that said first portion (18) and said second portion (19) of the body (6) each extend in a plane substantially perpendicular to the optical axis (X), in particular in the same plane perpendicular to the optical axis (X).

4. Optical element (2) according to claim 2 or 3, characterized in that the light guides (7) of the plurality of light guides are distributed along a second axis (Y), substantially perpendicular to the optical axis (X).

5. Optical element (2) according to one of the preceding claims, characterized in that each light guide (7) of the plurality of light guides comprises a cross-section to the direction in which it extends which has a substantially polygonal shape, in particular a rectangular shape.

6. Optical element (2) according to one of the preceding claims, characterized in that each light guide (7) of the plurality of light guides comprises a first end (8) linked to said body (6) and a second free end (9), a distance (D1) separating the second end (9) from two adjacent light guides (7) being less than or equal to 4 mm, and / or a length (L1) of each light guide (7) measured between its first end (8) and its second end (9) being greater than or equal to 7 mm.

7. Optical element (2) according to one of the preceding claims, characterized in that said plastic material is a transparent thermoplastic polymer, in particular polymethyl methacrylate or polyamide or polycarbonate.

8. Light module (1), characterized in that it comprises an optical element (2) according to one of the preceding claims and a set of light sources (3), a separate light source being positioned opposite each light guide (7) of the optical element.

9. A method of manufacturing by injection of plastic material an optical element (2) comprising a plurality of light guides (7) extending alongside each other, the optical element (2) further comprising a body (6) from which said light guides extend, the body comprising an injection point (17), the body comprising a first portion (18) interposed between said injection point and at least one first light guide (7A), the body comprising a second portion (19) distinct from the first portion (18) and interposed between said injection point and at least one second light guide (7B), the at least one second light guide (7B) being further from said injection point than the at least one first light guide (7A), the manufacturing method comprising: - the injection of molten plastic material through the injection point (17), then - simultaneously filling the at least one first light guide (7A) and the at least one second light guide (7B) with molten plastic material.

10. Injection mold configured to manufacture an optical element (2) according to one of claims 1 to 7.

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