Method for producing an optical component

Abstract

The invention relates to a method (1) for producing an optical component (2), characterised in that the production method (1) comprises: - a first step of injecting a first core (20.1), the first core (20.1) extending in a first direction; - a second step of injecting a first outer layer (21.1) encompassing the first core (20.1), the first core (20.1) and the first outer layer (21.1) forming a second core (20.2), characterised in that the first step of injecting the first core (20.1) comprises injecting first tabs (200.1) on either side of the first core (20.1) in a second direction perpendicular to the first direction.

Description

[0001] Description Title of the invention: Method for manufacturing an optical part [1] The present invention relates to a method for manufacturing an optical part. It also relates to a lighting device of a vehicle comprising an optical part manufactured according to said manufacturing method, as well as a rotary manufacturing mold for an optical part. It finds a particular but non-limiting application in motor vehicles. [2] A method for manufacturing an optical part, such as a lens, known to those skilled in the art comprises: - a step of injecting a first core, - a step of injecting a first external layer encompassing the first core, said first core and the first external layer forming a second core. Thus, several superimposed layers are obtained. There are as many steps of injecting layers superimposed on each other as are necessary to form the optical part.[3] A disadvantage of this state of the art is that due to the injection pressure, there may be a tilting of the first core forwards or backwards when material is injected around it. [4] In this context, the present invention aims to provide a manufacturing method which makes it possible to solve at least one of the disadvantages mentioned.[5] To this end, the invention proposes a method for manufacturing an optical part, characterized in that said manufacturing method comprises: - a first step of injecting a first core, said first core extending along a first direction, - a second step of injecting a first external layer encompassing said first core, said first core and said first external layer forming a second core, characterized in that the first step of injecting the first core comprises injecting first tabs on either side of said first core along a second direction perpendicular to the first direction. [6] The first tabs are configured to prevent, during the injection of the first external layer, a tilting of the first core around an axis substantially parallel to a second direction perpendicular to the first direction.[7] Thus, as will be seen in detail later, the first legs ensure the stability of the optical part in the mold between the injection steps. They also prevent deformations due to the core having tilted and thus improve the quality of the final part. [8] According to non-limiting embodiments, said manufacturing method may also comprise one or more additional features taken alone or in all technically possible combinations, among the following. [9] According to a non-limiting embodiment, the first legs are elongated along the second direction.

[0010] According to a non-limiting embodiment, the first legs have, in a section through a plane perpendicular to the second direction, an elongated shape.

[0011] According to a non-limiting embodiment, at least two first legs are injected at least on one side of the first core.

[0012] According to a non-limiting embodiment, said second step of injecting said first external layer is carried out by means of a material injection channel arranged between the at least two first legs.

[0013] According to a non-limiting embodiment, said manufacturing method further comprises for n an integer varying from 2 to N, with N>=3: - a 2n-1. ième n injection step ièmes legs which extend on either side of the nth core in the second direction, said step of injecting the n ièmes legs part of the n-1 injection step ième outer layer, - a 2n ième injection step of an n ième outer layer encompassing an n ième core, said n ième core and said n ième outer layer forming an n+1 ième core.

[0014] According to a non-limiting embodiment, the 2n-1 ièmeinjection step is optional for n>=3.

[0015] Throughout the description, the symbol ">=" means greater than or equal to.

[0016] According to a non-limiting embodiment, the n ièmes legs are far from the n-1 ièmes legs.

[0017] According to a non-limiting embodiment, the n ièmes legs are far from all p ièmes legs, p taking all integer values ​​between 1 and n-1.

[0018] According to a non-limiting embodiment, said manufacturing method further comprises a step of cutting the first legs.

[0019] According to a non-limiting embodiment, said manufacturing method further comprises a step of cutting the n ièmes legs, or some of the n ièmeslegs.

[0020] According to a non-limiting embodiment, said optical part comprises a light entry zone configured to be arranged opposite a light source and comprises a light exit zone.

[0021] According to a non-limiting embodiment, said optical part has an optical axis substantially perpendicular to the second direction.

[0022] According to a non-limiting embodiment, said manufacturing method comprises a step of cutting said material injection channel.

[0023] According to a non-limiting embodiment, the first core extends in its length along the first direction.

[0024] According to a non-limiting embodiment, the first core extends in its width along the second direction.

[0025] According to a non-limiting embodiment, the width of the first core is greater than its thickness which extends in a third direction.

[0026] According to a non-limiting embodiment, the optical part comprises a cut-off zone.

[0027] According to a non-limiting embodiment, the optical part comprises a light reflection zone in which the light is reflected by total internal reflection.

[0028] According to a non-limiting embodiment, the optical part comprises at least one collimator.

[0029] According to a non-limiting embodiment, the optical part has a light exit face which is a lens.

[0030] A lighting device of a vehicle is further provided, said lighting device comprising an optical part manufactured according to the manufacturing method according to any one of the preceding characteristics, and at least one light source. The light source is in particular arranged opposite the light entry zone of the optical part, and capable of emitting light rays in the direction of said light entry zone.

[0031] According to a non-limiting embodiment, the lighting device is a headlight, a rear light or an interior lighting device.

[0032] A rotary manufacturing mold for an optical part is further proposed, characterized in that said rotary mold comprises at least two injection stations and at least two cavities configured to receive the optical part during respectively one of the manufacturing steps of said optical part.

[0033] According to the invention, the first injection station is configured to carry out the first injection step of the manufacturing method according to the present disclosure, and the second injection station is configured to carry out the second injection step of the manufacturing method according to the present disclosure.

[0034] According to a non-limiting embodiment, the rotary mold comprises three injection stations.

[0035] According to a non-limiting embodiment, the rotary mold further comprises at least two cooling stations.

[0036] According to a non-limiting embodiment, the rotary mold comprises two injection stations, i.e. one for each of the first two injection steps, to which is added an injection station for each 2n. ième injection step when n>=2.

[0037] According to a non-limiting embodiment, the rotary mold comprises a number of injection cavities equal to the number of injection stations.

[0038] According to a non-limiting embodiment, the rotary mold comprises a demolding axis perpendicular to an optical axis of the optical part.

[0039] According to a non-limiting embodiment, the rotary mold comprises at least one drawer in the injection cavity associated with the 2N ièmeinjection step. This makes it possible to limit the risks of mold closure traces in optical functional parts and / or in aesthetic parts of the optical part.

[0040] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures:

[0041] [Fig.1a] is a flowchart of the steps of a method for manufacturing an optical part, the optical part comprising at least one core and two external layers, according to a non-limiting embodiment of the invention,

[0042] [Fig.1b] is a flowchart of the steps of a method for manufacturing an optical part, the optical part comprising at least one core and several external layers, according to a non-limiting embodiment of the invention,

[0043] [Fig.2] is a perspective view of a first non-limiting embodiment of the optical part manufactured according to the manufacturing method of Figures 1a and 1b, the optical part comprising a first core, a first outer layer, and a second outer layer,

[0044] [Fig. 3] is a perspective view of a first non-limiting embodiment of a first core with first legs of the optical part of Figure 2,

[0045] [Fig.4] is a longitudinal sectional view of the previous figure,

[0046] [Fig. 5] is a perspective view of a first non-limiting embodiment of a first outer layer of the optical part of Figure 2, the first outer layer encompassing the first core of Figure 3 and forming with this first core a second core,

[0047] [Fig.6] is a longitudinal sectional view of the previous figure,

[0048] [Fig.7] a perspective view of a first non-limiting embodiment of a second outer layer of the optical part of Figure 2, the second outer layer including the second core of Figure 5,

[0049] [Fig.8] a longitudinal sectional view of the previous figure,

[0050] [Fig.9] is a perspective view of a second non-limiting embodiment of the optical part manufactured according to the manufacturing method of Figures 1a and 1b,

[0051] [Fig.10] is a perspective view of a second non-limiting embodiment of a first core with first legs of the optical part of Figure 9,

[0052] [Fig.11] is a longitudinal sectional view of the previous figure,

[0053] [Fig. 12] a perspective view of a second non-limiting embodiment of a first external layer of the optical part of Figure 9, the first external layer encompassing the first core of Figure 10 and forming with this first core a second core,

[0054] [Fig.13] is a longitudinal sectional view of the preceding figure,

[0055] [Fig. 14] is a view of a second non-limiting embodiment of a second outer layer of the optical part of Figure 2, the second outer layer including the second core of Figure 12,

[0056] [Fig.15] is a longitudinal sectional view of the preceding figure,

[0057] [Fig. 16] is a schematic view of a vehicle equipped with a light device comprising an optical part according to the invention,

[0058] [Fig.17] a schematic view of a rotary mold for manufacturing an optical part according to the manufacturing method of Figures 1a and 1b.

[0059] Elements that are identical, by structure or by function, appearing in different figures retain, unless otherwise specified, the same references.

[0060] The manufacturing method 1 of an optical part 2 according to the invention is described with reference to FIGS. 1a and 1b, and the manufactured optical part 2 is described with reference to FIGS. 2 to 16.In a non-limiting embodiment, the optical part 2 is an optical part for a vehicle 3 (illustrated in FIG. 16). In a non-limiting embodiment, the vehicle 3 is a motor vehicle.

[0061] The optical part 2 may be integrated into a lighting device 4 (illustrated schematically in FIG. 16) which also comprises at least one light source 40. The latter is arranged opposite the optical part 2. In non-limiting embodiments, the lighting device 4 is a headlight or a rear light or an interior lighting device of a motor vehicle 3. In the non-limiting example illustrated in FIG. 16, the optical part 2 is integrated into a headlight.

[0062] In a non-limiting embodiment, said at least one light source 40 is a semiconductor light source.In a non-limiting embodiment, the semiconductor light source is part of a light-emitting diode or a laser diode. By light-emitting diode, we mean any type of light-emitting diode, whether in non-limiting examples LEDs (“Light Emitting Diode” in English), OLEDs (“Organic LED” in English), AMOLEDs (“Active-Matrix-Organic LED” in English), or FOLEDs (“Flexible OLED” in English). Said at least one light source 40 is configured to generate light rays R.

[0063] The optical part 2 has an optical axis A-A' shown in FIGS. 2 and 9.It extends in its length in a first direction X (otherwise called elongation direction), in its width in a second direction Y (otherwise called transverse direction Y) perpendicular to the first direction X, and in its thickness in a third direction Z (otherwise called thickness direction Z) perpendicular to the first direction X and to the second direction Y.

[0064] The optical part 2 comprises a light entry zone 23 configured to be arranged opposite said at least one light source 40 and to receive the light rays R emitted by the light source 40. The optical part 2 comprises a light exit zone 24 through which a light beam Fx formed by the light rays R can exit. The light beam Fx emerges substantially along the optical axis A-A'.By substantially along the optical axis, it is understood that the beam defines what is commonly called a light cone, and that the optical axis is located inside said light cone. The light cone has an angular aperture which may be different depending on the direction considered.

[0065] In a non-limiting embodiment not illustrated, the optical part 2 forms a projection lens, otherwise called a lens. In this case, the optical part 2 has a simple and conventionally symmetrical shape.

[0066] In another non-limiting embodiment illustrated in Figures 2 and 9, the optical part 2 comprises at least one collimator 26, and a light reflection zone 27 in which in particular the light is reflected by total internal reflection. The optical part 2 has a light exit face 28 which is a lens. The lens 28 is a diopter located at one end of the optical part 2.It can be observed in this case that the optical part 2 has a complex and non-symmetrical shape. In a non-limiting variant embodiment illustrated in FIG. 9, the optical part 2 comprises a cut-off zone 29. The cut-off zone 29 is configured to generate a cut in the beam projected by the optical part 2 resulting from the manufacturing method 1, when the light source 40 is in its position of use, and switched on. In this non-limiting embodiment, the light rays R from the light source 40 enter the optical part 2 via the collimators 26 and will be reflected on the reflector 27 to form a light beam Fx which will be directed towards the lens 28 along the optical axis A-A' and exit via the light exit zone 24.

[0067] The optical part 2 is a thick part. In a non-limiting embodiment, its thickness is between 5 mm and 50 mm (millimeters).In a non-limiting variant embodiment, its thickness is between 10 and 40 mm. In another non-limiting variant embodiment, its thickness is between 14 mm and 37 mm.

[0068] The optical part 2 comprises: - a first core 20.1, - a first external layer 21.1 which encompasses the first core 20.1, the first external layer 21.1 and the first core forming a second core 20.2.

[0069] In the remainder of the description, the reference 20 is used to designate a core in general, and the reference 21 is used to designate an external layer in general. The references 20.1, 20.2, …20.n are used to designate a first core, a second core, an n. ième core. References 21.1, 21.2, …21.n are used to designate a first outer layer, a second outer layer, a n ièmeouter layer.

[0070] It will be noted that having several superimposed layers is advantageous when the optical part 2 has a significant thickness. This makes it possible to reduce the time required for the material to solidify during injection. Indeed, a part injected in a single very thick block takes a long time to cool down to the core, whereas each layer can be cooled quickly, and the overall time required to successively cool all the layers is shorter than the time required to cool the equivalent block.

[0071] In a non-limiting embodiment, the optical part 2 further comprises: - a second outer layer 21.2 which encompasses the second core 20.2.

[0072] In a non-limiting embodiment, the optical part 2 comprises at least two outer layers 21.

[0073] The second outer layer 21.2 is illustrated according to a first non-limiting embodiment in the perspective figures 7 and in section 8, according to a second non-limiting embodiment in the perspective figures 10 and in section 11, and according to a third non-limiting embodiment in the perspective figures 14 and in section 15.

[0074] In a non-limiting embodiment, the optical part 2 may comprise more than two external layers.

[0075] The manufacturing method 1 of the optical part 2 is described below with reference to figures 1a and 1b in a non-limiting embodiment in which the manufacturing method 1 makes it possible to manufacture an optical part 2 with at least: - a first core 20.1, and - a first external layer 21.1, and - a second core 20.2 and a second external layer 21.2.

[0076] To manufacture an optical part 2 with a first core 20.1, a first outer layer 21.1, a second core 20.2 and a second outer layer 21.2, the manufacturing method 1 thus comprises the following steps as illustrated in Figure 1a.

[0077] In a first step E1 illustrated F1(20.1, 200.1) in Figure 1a, a first core 20.1 is injected. The first core 20.1 extends in its length along the elongation direction X. It extends in its width along the transverse direction Y. Its width is greater than its thickness which extends along the thickness direction Z. In a non-limiting embodiment, the injected material is made of PC (Polycarbonate) PMMA (Polymethylmethacrylate) or polyamide, or any other transparent optical material.

[0078] The first core 20.1 is illustrated according to a first non-limiting embodiment in the perspective figures 3 and in section 4, and according to a second non-limiting embodiment in the perspective figures 10 and in section 11. It can be noted that in figures 10 and 11, the first core 20.1 has a slope 200.9 which makes it possible to obtain the cutting zone 29 illustrated in Figure 9.

[0079] As illustrated in Figures 3 and 10, it can be noted that the first core 20.1 has an asymmetrical shape. Furthermore, its shape is complex, it notably presents sudden variations in thickness.

[0080] The first legs 200.1 are injected at the same time as the injection of the first core 20.1.

[0081] In a non-limiting embodiment, the first legs 200.1 extend on either side of the first core 20.1 along the second direction Y perpendicular to the thickness direction Z of the first core 20.1. The first legs 200.1 are perpendicular to the first direction X. In a non-limiting embodiment, the first legs 200.1 are elongated along the second direction Y. In a non-limiting embodiment, the first legs 200.1 have in a section through a plane perpendicular to the second direction Y a thickness substantially equal to the thickness of the first core 20.1. This prevents the bending of said first legs 200.1, and thus makes it possible to maintain the first core 20.1 in position while it is overmolded during the injection of the next layer.

[0082] Due to the injection pressure, there may be a tilting of the first core 20.1 forwards or backwards when material is injected around the first core 20.1. The first legs 200.1 are configured so as to prevent the first core 20.1 from pivoting forwards or backwards. They keep it stationary during the injection of the first external layer 21.1. In particular, the first legs 200.1 are configured so as, during the injection of the first external layer 21.1, prevent tilting of the first core around an axis E-E' (illustrated in figures 3 and 10) which is substantially parallel to the second direction Y. These first legs 200.1 are in fact held by a rotary manufacturing mold 6 (illustrated in figure 17), when it is closed, in particular by a fixed part and a movable part which close on these first legs 200.1. The first legs 200.1 are thus pinched (i.e. sandwiched) in the rotary manufacturing mold 6 which is conventionally made of steel and thus held by the latter which makes it possible to hold on either side the first core 20.1 which is arranged in a cavity of the rotary manufacturing mold 6 without being retained by the latter but is floating in the cavity. In a non-limiting embodiment, the manufacturing mold comprises three cavities referenced 61.1, 61.2, 61.3 to receive the first core 20.1.

[0083] The location of the first legs 200.1 depends on structural calculation results from rheological simulations carried out upstream. This makes it possible to identify the correct distance at which to position the first legs 200.1 on a given layer to avoid tilting during overmolding by a second layer. The center of rotation, the amplitude of the deformations of the insert (core) during overmolding and therefore the installation of the structural reinforcements with these first legs 200.1 are identified.

[0084] In a non-limiting embodiment, the first legs 200.1 have, in a section through a plane perpendicular to the second direction Y, an elongated shape. Thus, when there are only two first legs 200.1, namely centered on the axis E-E' and on either side of the first core 20.1, this prevents the first core 20.1 from tilting.

[0085] In a non-limiting embodiment, at least two first legs 200.1 are injected at least on one side of the first core 20.1.In a non-limiting embodiment illustrated in Figures 3 and 10, at least two first legs 200.1 are injected on each side of the first core 20.1. There are thus four first legs 200.1, two of which are on one side of the first core 20.1 and two others on the other side of the first core 20.1. This prevents the first core 20.1 from tilting. In a non-limiting embodiment illustrated in Figures 5 and 12, the two first legs 200.1 which are injected on one side of the first core 20.1 are spaced apart to allow for the possibility of having a first material injection channel 25.1. Thus, in a non-limiting embodiment, a first material injection channel 25.1 is arranged between the at least two first legs 200.1. There is thus an injection point I between the two first legs 200.1. This first material injection channel 25.1 is used to inject the first external layer 21.1.

[0086] In a step E2 illustrated F2(21.1, 200.2) in Figure 1a, a first outer layer 21.1 encompassing the first core 20.1 is injected. It will be noted that this first outer layer 21.1 does not encompass the first legs 200.1. The first core 20.1 and the first outer layer 21.1 form a second core 20.2 referenced in Figures 6 and 13. In a non-limiting example, the first outer layer 21.1 has a thickness substantially equal to 3mm (millimeters). Thus, as the first outer layer 21.1 is located all around the first core 20.1, there is a thickness of 6mm in total added on either side of the first core 20.1. Thus, a single layer of 6mm is deposited. This reduces the manufacturing cycle time of the optical part 2.

[0087] The first external layer 21.1 is illustrated according to a first non-limiting embodiment in the perspective figures 5 and in section 6, and according to a second non-limiting embodiment in the perspective figures 12 and in section 13.It can be noted that in Figures 12 and 13, the first external layer 21.1 has a slope 210.9 which makes it possible to obtain the cut-off zone 29 illustrated in Figure 9.

[0088] It can be noted in Figures 6 and 13 that like the first core 20.1, the second core 20.2 has a non-symmetrical shape and a complex shape in which there are sudden variations in thickness.

[0089] In a non-limiting embodiment, step E2 comprises, at the same time as the injection of the first external layer 21.1, the injection of second tabs 200.2 which extend on either side of the first external layer 21.1 along the second direction Y. More precisely, the second tabs 200.2 extend on either side of the second core 20.2 along the second direction Y perpendicular to the thickness direction Z of the second core 20.2. The second tabs 200.2 are perpendicular to the first direction X.In a non-limiting embodiment, the second legs 200.2 are elongated along the second direction Y. In a non-limiting embodiment, the second legs 200.2 have a width substantially equal to the thickness of the first core 20.1, as has been described for the first legs 200.1.

[0090] These second legs 200.2 are substantially parallel to the first legs 200.1.

[0091] Figures 12 to 15 illustrate these second legs 200.2.

[0092] Due to the injection pressure, there may be a tilting of the second core 20.2 forwards or backwards when material is subsequently injected around the second core 20.2. The second legs 200.2 are configured so as to prevent the second core 20.2 from pivoting forwards or backwards. They keep it immobile during the injection of a second external layer 21.2 illustrated in figure 15. In particular, the second legs 200.2 are configured to, when injecting a second outer layer 21.2, prevent tilting of the second core 20.2 around an axis F-F' (illustrated in FIG. 12) which is substantially parallel to the second direction Y. The axis F-F' is substantially parallel to the second legs 200.2 and passes through its second legs 200.2. As for the first legs 200.1, these second legs 200.2 are held by the rotary manufacturing mold 6 when it is closed, in particular by a fixed part and a movable part which close on these second legs 200.2. The second legs 200.2 are thus pinched (i.e. sandwiched) in the rotary manufacturing mold 6 and thus held by the latter, which makes it possible to maintain on either side the second core 20.2 which is arranged in a cavity 61 of the rotary manufacturing mold 6 without being retained in the latter but is floating in the cavity 61.

[0093] As the optical part 2 is elongated in the first direction X, in a non-limiting embodiment, the second legs 200.2 are distant from the first legs 200.1. This makes it possible to compensate even more for the risk of tilting. By "distant" is understood throughout the present description that the second legs 200.2 are arranged relative to the first legs 200.1 at a distance greater than the size in the first direction X of the first legs 200.1. In a non-limiting example, if there is only one first leg on one side of the first core 20.1, the size in the first direction X corresponds to the dimension in the first direction X of the section through a plane perpendicular to the second direction Y of said first leg. In another non-limiting example, if there are several first legs on one side of the first core 20.1, the size along the first direction X corresponds to the distance along the first direction X taken between the most extreme faces, along said first direction X, of all of said first legs located on the same side of the core 20.1. The location of the second legs 200.2 depends on structural calculation results from rheological simulations carried out upstream. This makes it possible to identify the correct distance at which to position the second legs 200.2 on a given layer to avoid tilting during overmolding by a second layer. The center of rotation, the amplitude of the deformations of the insert (core) during overmolding and therefore the installation of the structural reinforcements with these second legs 200.2 are identified. In other words, the rheological simulations make it possible to determine the exact position of the second legs 200.2, around the remote position.

[0094] In a non-limiting embodiment illustrated, a second tab 200.2 is injected on each side of the second core 20.2. There are thus two second tabs 200.2, one on one side of the second core 20.2 and the other on the other side of the second core 20.2.

[0095] In another non-limiting embodiment not illustrated in FIG. 12, several second tabs 200.2 are injected on each side of the second core 20.2.

[0096] In a step E3 illustrated F3(21.2, 20.2) in FIG. 1a, a second external layer 21.2 encompassing the second core 20.2 is injected. The assembly of the second core 20.2 and the second external layer 21.2 forms a third core 20.3 illustrated in Figures 8 and 15, third core 20.3 which forms the optical part 2 illustrated respectively in Figures 2 and 9. It will be noted that this second external layer 21.2 does not include the second legs 200.2.

[0097] It can be noted in Figures 7 and 14 that like the first core 20.1 and the second core 20.2, the third core 20.3 has a non-symmetrical and complex shape.

[0098] The second external layer 21.2 illustrated in Figure 7 according to a first non-limiting embodiment, makes it possible to produce an optical part 2 illustrated in Figure 2 which is configured to generate a light beam Fx of the “flat” type in English, “plat” in French. It forms a part of a code beam, namely the flat portion, that is to say having a flat cutoff.

[0099] The second external layer 21.2 illustrated in Figure 14 according to a second non-limiting embodiment, makes it possible to produce an optical part 2 illustrated in Figure 9 which is configured to generate a light beam Fx of the “kink” type in English, “coudé” in French. It forms a part of a code beam, namely the bent portion, that is to say having a bent cutoff, with in particular an inclined part.

[0100] Thus, thanks to this manufacturing method 1, it is possible to produce with good precision a complex and non-symmetrical optical part 2, in particular an optical part 2 composed of at least one collimator 26, a reflector 27 and a lens 28.

[0101] When all the cores 20 and the external layers 21 necessary for the optical part 2 have been injected, the following steps are carried out.

[0102] In a non-limiting embodiment, in a step E4 illustrated F4(200.1, 200.2, OFF) in FIG. 1a, the first legs 200.1 are cut as well as the second legs 200.2. Thus, all the legs 200 which have been injected and which have served to hold the cores in position are cut. This makes it possible to lighten the optical part 2, and to limit its size. It should be noted that if the first legs 200.1 and / or the second legs 200.2 are not cut, they can be used to fix the optical part 2 in the lighting device 1.

[0103] In a non-limiting embodiment, the manufacturing method 1 further comprises a step E1' illustrated F1'(20.1, 200.1) in FIG. 1a of cooling the first core 20.1 and the first legs 200.1 which were injected during step E1. This step E1' is carried out before step E2.

[0104] In a non-limiting embodiment, the manufacturing method 1 further comprises a step E2' illustrated F1'(21.1, 200.2) in FIG. 1a of cooling the first external layer 21.1 which was injected during step E2 with, where appropriate, the second legs 200.2. This step E2' is carried out before step E3.

[0105] In a non-limiting embodiment, the manufacturing method 1 further comprises a step E3' illustrated F3'(21.2) in FIG. 1a of cooling the second external layer 21.2 which was injected during step E3.

[0106] Thus, in a non-limiting embodiment, as soon as a core 20.1, 20.2 or an external layer 21.1, 21 is injected.2, it is cooled immediately after and before the injection of another element (core 20.1, 20.2 or external layer 21.1, 21.2) of the optical part 2. In other words, the manufacturing method 1 comprises as many steps of cooling a core 20.1, 20.2 as there are cores 20.1, 20.2 in the optical part 2 to be manufactured, and as many steps of cooling an external layer 21.1, 21.2 as there are external layers 21.1, 21.2 in the optical part 2 to be manufactured. It will be noted that the use of a cooling station for a given layer depends on the thickness of the layer in question, the space required in the mold and the number of stations available.

[0107] It will be noted that steps E1, E2 can be repeated as many times as desired to add several cores 20 and several external layers 21.

[0108] Thus, in the case where one wishes to manufacture an optical part 2 with a first core 20.1 and more than two external layers 21, as illustrated in Figure 1b, the manufacturing method 1 comprises for n integer varying from 2 to N, with N>=3: - the first step E1 (described previously) illustrated F1(20.1, 200.1) of injecting a first core 20.1, said first core 20.1 extending along a first direction X, this first step comprising the injection of first legs 200.1 on either side of said first core 20.1 along a second direction Y perpendicular to the first direction X, - a 2n-1. ième n injection step ièmes legs that extend on either side of the n ième core 20.n along the second direction Y, said step of injecting the n ièmes legs part of the n-1 injection step ième outer layer 21.n-1, - a 2n ième injection step of an n ième outer layer 21.n encompassing an n ième core 20.n, said n ième core 20.n and said nième outer layer 21.n forming an n+1 ième core 20.n+1.

[0109] In a non-limiting embodiment, the manufacturing method 1 further comprises a step E1' illustrated F1'(20.1, 200.1) in Figure 1b of cooling the first core 20.1 and the first legs 200.1 which were injected during step E1.

[0110] In a non-limiting embodiment, the manufacturing method 1 further comprises a step E2' illustrated F1'(21.n, 200.n) in Figure 1b of cooling the n ième outer layer 21.n which was injected during step E2 with the n ièmes legs 200.n.

[0111] Steps E2 and E2' are repeated until N is reached.

[0112] According to a non-limiting embodiment, the 2n-1 ièmeinjection step is optional for n>=3. Indeed, when the first legs 200.1 and the second legs 200.2 are present, and in particular when the latter are distant from the first, this may be sufficient to guarantee the stability of the optical part 2 in the mold, in particular when the dimension of the optical part 2 changes little in the first direction X in the subsequent steps. This facilitates the design and production of the mold, as well as the steps where the legs are cut.

[0113] According to a non-limiting embodiment, the n ièmes legs 200.n are far from n- 1 ièmes legs 200.n-1.

[0114] According to a non-limiting embodiment, the n ièmes legs 200.n are far from all p ièmeslegs 200.p, p taking all integer values ​​between 1 and n-1.

[0115] The distance between the legs makes it possible to compensate even more for the risk of tilting when the optical part is particularly elongated in the X direction. In particular, when the optical part 2 elongates significantly during an injection step, it is advantageous to have at the level of the portion of said elongation new legs distant from the previous legs.

[0116] The term “distant” applies to the n ièmes legs 200.n, n-1 ièmes legs 200.n-1 and p ièmeslegs 200.p in a manner analogous to what was previously described for the second legs 200.2 and first legs 200.1.

[0117] The spacing of the legs described above can be applied when the 2n-1th injection step is present.

[0118] When all the cores 20 and outer layers 21 necessary for the optical part 2 have been injected, the following steps are carried out.

[0119] In a step E3 illustrated F3(200.1, 200.n, OFF) in Figure 1b, the first legs 200.1 are cut as well as the nth legs 200.n. Thus, all the legs 200 that have been injected and that have served to hold the cores in position are cut.Alternatively, only some of the legs are cut, in particular in order to lighten the optical part 2, and other legs are kept, in order to be used to fix the optical part 2 in the lighting device 1

[0120] A rotary manufacturing mold 6 is used to manufacture the optical part 2 according to the manufacturing method 1 described previously. The rotary manufacturing mold 6 is illustrated in FIG. 17. The rotary manufacturing mold 6 is otherwise called rotary mold 6 or mold 6.

[0121] The mold 6 comprises at least two injection stations and at least two cavities configured to receive the optical part 2 during respectively one of the manufacturing steps of said optical part 2. It will be noted that a manufacturing step is either a step of injecting a core 20, or a step of injecting an external layer 21.

[0122] The following description explains the use of the rotary mold 6 for manufacturing an optical part 2 composed in a non-limiting embodiment of a first core 20.1 with first legs 200.1, a first external layer 21.1 with, where appropriate, second legs 200.2 and a second external layer 21.2. In this case, in an illustrated non-limiting embodiment, the rotary mold 6 comprises three injection stations 60.1, 60.2 and 60.3 and respectively three cavities 61.1, 61.2 and 61.3. In the remainder of the description, the reference 60 is used to designate an injection station in general, the reference 61 is used to designate a cavity in general, and the reference 62 is used to designate a cooling station in general.

[0123] The injection stations 60.1, 60.2 and 60.3 are stationary while the cavities 61.1, 61.2 and 61.3 are mobile.In a non-limiting embodiment, they are arranged on a movable and rotating plate 600.

[0124] The first injection station 60.1 makes it possible to carry out the first step E1, namely the injection of the first core 20.1 of the optical part 2 with the first legs 200.1. The first core 20.1 is located in a first cavity 61.1.

[0125] Then, the plate 600 rotates to bring the first core 20.1 in front of the second injection station 60.2. The second step E2 can be carried out, namely the injection of the first external layer 21.1 of the optical part 2 with, where appropriate, the second legs 200.2.

[0126] Then, the plate 600 rotates again to bring the second core 20.2 (formed by the first core 20.1 and the first external layer 21.1) in front of the third injection station 60.3. The third step E3 can be carried out, namely the injection of the second external layer 21.2 of the optical part 2.

[0127] It will be noted that the first legs 200.1 and the second legs 200.2 are held by a movable part and a fixed part (not shown) of the rotary mold 6.

[0128] Finally, the optical part 2 is demolded from the rotary mold 6: it is thus removed from the third cavity 61.3. When the optical part 2 is extracted from the rotary mold 6, the first legs 200.1 and the second legs 200.2 can be cut.

[0129] In a non-limiting embodiment, the rotary mold 6 further comprises at least two cooling stations 62.

[0130] In a non-limiting embodiment, the rotary mold 6 further comprises as many cooling stations 62.1, 62.2, 62.3 etc. that there are cavities 61.1, 61.2, 61.3 etc. It should be noted that the use of a cooling station for a given layer depends on the thickness of the layer in question, the space required in the mold and the number of stations available.In the non-limiting example illustrated in Figure 17, it comprises three cooling stations 62.1, 62.2 and 62.3.

[0131] Before presenting the optical part 2 being manufactured to a next injection station 60, it is presented to a cooling station 62 to cool it. As can be seen, there is an alternation of cavities 61 and cooling stations 62.

[0132] Thus, after the injection of the first core 20.1 and the first legs 21.1, in a non-limiting embodiment, the rotary mold 6 rotates to present them to a first cooling station 62.1. Similarly, after the injection of the first external layer 21.1 and, where appropriate, the second legs 200.2, in a non-limiting embodiment, the rotary mold 6 rotates again to present them to a second cooling station 62.2. Finally, after the injection of the second outer layer 21.2, in a non-limiting embodiment, the rotary mold 6 rotates again to present the optical part 2 to a third cooling station 62.3.

[0133] It will be noted that with this non-limiting example of rotary mold 6, three different optical parts 2 can be produced simultaneously which will be at different stages of manufacture and which are in different cavities 61. Thus, while at the third injection station 60.3 an optical part 2 (which is arranged in the first cavity 61.1 for example) is being finished by injecting a second external layer 21.2, the injection of the first external layer 21.1 and, if applicable, the second legs 200.2 of a second optical part 2 (which is arranged in the second cavity 61.2 for example) can be carried out at the second injection station 60.2 and the injection of the first core 20.1 with first legs 200 can be started.1 for a third optical part 2 (which is arranged in the third cavity 61.3 for example) at the first injection station 60.1. Thus, process time is saved for manufacturing several optical parts 2. It will be noted that the three optical parts 2 which are being manufactured at the same time are cooled in parallel instead of cooling one optical part 2 each time. This saves overall cooling time.

[0134] It will be noted that of course, the rotary mold 6 can include additional injection stations 60 and cooling stations 62 if there are additional cores 20 and external layers 21.

[0135] In a non-limiting embodiment, the demolding axis C-C' of the optical part 2 is perpendicular to the optical axis A-A' of the optical part 2. The demolding axis C-C' corresponds to the demolding axis of the mold 6.This makes it possible to simplify the demolding of the optical part 2 and to avoid too many undercuts. If the demolding axis C-C' of the optical part 2 were parallel to the optical axis A-A', it would be too complex to demold and there would be too many undercuts due to the complexity of the optical part 2.

[0136] Of course, the description of the invention is not limited to the embodiments described above and to the field described above. Thus, in another non-limiting embodiment, it is possible to have two injection channels 25.1 arranged on each side of the first core 20.1 and between the two first legs 200.1 on each side of the first core 20.1 as illustrated in FIGS. 7 or 14.

[0137] Thus, the invention described has in particular the following advantages: - it makes it possible to manufacture an optical part 2 of complex and asymmetrical shape, - it makes it possible to manufacture an optical part 2 of significant thickness, - it makes it possible, during the encapsulation of a core 20 by an external layer 21, to prevent a shift of the core and consequently to avoid having a different shape with dimensions different from the originally planned design. This better respects the originally planned shape. It will be noted that in the event of a shift of the core, the optical part 2 no longer has the expected shape, which affects the light beam generated by the optical part 2, - it prevents tilting of the overmolded core 20 which can cause deformations ranging from warping to breakage via cracking depending on the amplitude of the tilting, when the material relaxes.- it allows to have a compliant optical part 2 even in the case of material flows during injection which are not balanced due to an asymmetrical shape, - it allows thanks to the first legs 200.1 and second legs 200.2 to manufacture an asymmetrical and complex part compared to a non-complex symmetrical part for which one would also use cores and layers encapsulated from each other.

Claims

Claims

1. A method of manufacturing (1) an optical part (2), characterized in that said manufacturing method (1) comprises: - a first step of injecting a first core (20.1), said first core (20.1) extending along a first direction (X), - a second step of injecting a first outer layer (21.1) encompassing said first core (20.1), said first core (20.1) and said first outer layer (21.1) forming a second core (20.2), characterized in that the first step of injecting the first core (20.1) comprises injecting first tabs (200.1) on either side of said first core (20.1) along a second direction (Y) perpendicular to the first direction (X).

2. A manufacturing method (1) according to claim 1, wherein the first legs (200.1) are elongated along the second direction (Y).

3. Manufacturing method (1) according to claim 1 or 2, wherein the first legs (200.1) have, in a section through a plane perpendicular to the second direction (Y), an elongated shape.

4. Manufacturing method (1) according to any one of the preceding claims, wherein at least two first legs (200.1) are injected at least on one side of the first core (20.1).

5. Manufacturing method (1) according to the preceding claim, wherein said second step of injecting said first outer layer (21.1) is carried out by means of a material injection channel (25.1) arranged between the at least two first legs (200.1).

6. Manufacturing method (1) according to any one of the preceding claims, wherein said manufacturing method (1) further comprises for n integer varying from 2 to N, with N>=3: - a 2n-1. ième n injection step ièmeslegs which extend on either side of the nth core (20.n) in the second direction (Y), said step of injecting the n ièmes legs part of the n-1 injection step ième outer layer (21.n-1), the 2n-1 ième injection step being optional for n>=3; - a 2n ième injection step of an n ième outer layer (21.n) encompassing an n ième core (20.n), said n ième core (20.n) and said n ième outer layer (21.n) forming an n+1 ième kernel (20.n+1).

7. A manufacturing method (1) according to any preceding claim, wherein said manufacturing method (1) further comprises a step of cutting the first legs (200.1).

8. A manufacturing method (1) according to claim 6 and claim 7, wherein said manufacturing method (1) further comprises a step of cutting the n ièmeslegs (200.n), or some of the n ièmes legs (200.n).

9. Manufacturing method (1) according to any one of claims 6 to 8, wherein the n ièmes legs (200.n) are far from the n-1 ièmeslegs (200.n-1).

10. Manufacturing method (1) according to any one of the preceding claims, wherein said optical part (2) comprises a light entry zone (26) configured to be arranged opposite a light source (40) and comprises a light exit zone (24).

11. Lighting device (4) of a vehicle (3), said lighting device (4) comprising an optical part (2) manufactured according to the manufacturing method (1) according to any one of the preceding claims, and at least one light source (40).

12. Lighting device (4) according to the preceding claim, wherein the lighting device (4) is a projector, a rear light or an interior lighting device.

13. Rotary manufacturing mold (6) for an optical part (2), characterized in that said rotary mold (6) comprises at least two injection stations (60) and at least two cavities (61) configured to receive the optical part (2) during respectively one of the manufacturing steps of said optical part (2), a first injection station (60.1) being configured to carry out the first injection step of the manufacturing method (1) according to any one of the preceding claims 1 to 10, and a second injection station (60.2) being configured to carry out the second injection step of the manufacturing method (1) according to any one of the preceding claims 1 to 10.

14. Rotary mold (6) according to claim 13, wherein the rotary mold (6) comprises three injection stations (60), and optionally further at least two cooling stations (62).

15. A rotary mold (6) according to claim 13 or claim 14, wherein the rotary mold (6) comprises a demolding axis (C-C') perpendicular to an optical axis (A-A') of the optical part (2).

Images