Optical component comprising an array of microlenses having curvatures

Abstract

The invention relates to an optical component (1) comprising an array (11) of microlenses (11(i,j)) comprising a sub-array in which, on each row or column: each microlens (11(i,j)) has a first edge (b2(i,j)) projecting from an edge (b1(i+1,j)) of one of the microlenses (11(i+1,j)) of lower or higher rank, the first edge and said edge of one of the microlenses (11(i+1,j)) of lower or higher rank being connected by a first wall (m_i+1) located in a first plane (P(i+1)) parallel to a main optical direction (X), and also a second edge (b1(i,j)) set back from an edge (b2(i-1,j)) of the other of the microlenses (11(i-1,j)) respectively of higher or lower rank, the second edge and said edge of the other of the microlenses (11(i+1,j)) of higher or lower rank being connected by a second wall (m_i) located in a second plane (P(i)) parallel to the main optical direction (X). (Figure 8)

Description

[0001]DESCRIPTION Title of the invention: Optical component comprising a microlens array with curvatures The present invention relates to the field of optics, and more specifically concerns an optical component comprising a microlens array, finding particular application in the automotive field. Vehicles, and in particular motor vehicles, are commonly equipped with headlights that generate various lighting functions, including road illumination and vehicle signaling to other road users. The lighting corresponds to a high beam function or a low beam function. The signaling function corresponds, for example, but not limited to, a position light function or a turn signal function. For reasons of style and aesthetics, for example,Light modules can be designed to follow certain surfaces of the vehicles they are intended to equip, such as the outer lens of a headlight or the front of the vehicle. These vehicle surfaces are not always flat, so it is necessary to adapt the light modules to follow these non-planar surfaces. Furthermore, it is also possible to encounter a relatively flat outer lens or front panel and want to create a light module that deviates from it to create an impression of depth. In both cases, the light modules are configured so that their output face—that is, the face intended to be in contact with the outer lens or front panel—has a controlled and adapted shape. In certain applications,The realization of one of the aforementioned lighting functions is made possible by the emission of light rays from a light source through a microlens array, also known by the English acronym MLA (microlens array). A microlens array notably comprises light channels formed by an input microlens and an output microlens, which are respectively focused so that light rays entering through an input microlens propagate through a dedicated light channel within the microlens array, exiting through the output microlens associated with that channel. Microlens arrays with an opaque mask are known, and on either side of this mask are attached an input microlens array and an output microlens array.Each matrix is ​​focused on the mask, and apertures are formed in the mask. Maskless microlens arrays are also known, with an output microlens array directly attached to the input microlens array, and with input microlenses converging on the corresponding output microlens and output microlenses focused on the corresponding input microlens. It is advantageous to fabricate a microlens array by plastic injection molding to give it a specific curvature, notably by offsetting the input faces of the input microlenses and / or the output faces of the output microlenses. In the context of plastic injection molding of the microlens array,Draft angles must be provided from a flow channel to the adjacent channel to allow for demolding of the part after injection. While the presence of draft angles, necessary for mechanical considerations, must not have optical consequences, creating these draft angles in molds configured for microlens formation, with dimensions on the order of millimeters, for example, between 0.3 mm and 10 mm, is difficult to implement. The inventors, seeking to imprint the curvature of a vehicle onto a microlens matrix, observed that when the microlenses are intended to cover the surface of a glass plate with an overall doubly curved shape, that is, with curvatures in distinct directions, and with at least one microlens that is prominent relative to microlenses arranged on either side of this prominent microlens,The formation of a corresponding metal mold is made difficult, particularly when creating the counterform corresponding to this prominent microlens. This can result in significantly reducing the size of neighboring counterforms and consequently altering the useful optical surfaces of some of the microlenses. Figure 1 shows how such a mold 2 is made. A tool 3, for example a milling cutter, machines a metal surface intended to form the mold 2, modeled by the inventors during testing. Given the very small dimensions of the microlens array to be produced, and the size of the machine incorporating the tool 3,The mold 2 being manufactured and the tool 3 have very little range of motion relative to each other. In particular, the tool 3 cannot carve the metal surface without presenting an angle greater than 5 degrees to a demolding direction. This demolding direction is approximately orthogonal to each counterform of the mold designed to form an optical surface of a microlens. It is, in fact, parallel to the principal optical direction of the microlens array formed by the mold, when the array is still embedded in the mold. For simplicity in this example, we assume that the tool 3 can only work parallel to the cutting plane of Figure 1. The tool 3 must form, on the surface of the mold 2, a first counterform 20, a second counterform 21, and a third counterform 22.each designed to form the optical surface of a microlens. The second counterform 21 is sandwiched between two risers formed by the first counterform 20 and the third counterform 22. The counterforms are each substantially orthogonal to the demolding direction, and the risers have a draft angle, typically on the order of 1° to 3°, to allow the demolding of the microlens matrix that will subsequently be formed in the mold 2. In Figure 1, the risers are schematically represented substantially parallel to the demolding direction, in a theoretical orientation, to emphasize the difference with the orientation of the riser actually produced by machining with tool 3. Tool 3 can fully produce the first counterform 20 and the third counterform 22, as these counterforms are easily accessible on the metal surface of the mold 2. However,Tool 3 cannot fully produce the second counterform 21. More specifically, one of the risers 30, as well as a portion 31 of the second counterform 21, located in the direct extension of the riser 30, cannot be produced without deforming the second and third counterforms 21, 22 as they should be. Figure 2 shows that after the passage of tool 3, the riser 30 is not, in practice, produced substantially parallel to the demolding direction, with a draft angle as previously mentioned, but with a clearance angle θ whose value is much greater than that of the draft angle, and for example greater than or equal to five degrees. As can be seen in Figure 2, this has the effect of trimming a portion 220 of the third counterform 22, which is nevertheless easily accessible by tool 3. Furthermore, since tool 3 cannot cut directly against the metal surface,surfaces having a radius of curvature R less than 0.3 mm, trims a portion 210 of the second counterform 21, at the junction between this second counterform 21 and the riser 30. Figure 3 illustrates areas 32 of the mold 2 as identified by the inventors during their tests as having counterforms suitable for forming trimmed optical surfaces because one of these counterforms is boxed between more than two other counterforms. Indeed, as explained in relation to Figures 1 and 2, the tool 3 cannot easily create a boxed counterform by working perpendicular to two risers on either side of the counterform and located directly above the edges of the counterform. Nor can it easily create it by working parallel to these two risers.since it is then limited by a final riser perpendicular to these two risers. Such a mold therefore produces a matrix of counterforms, some of which produce degraded optical surfaces, and this is all the more pronounced as the counterforms are small. When the microlens matrix formed by the mold is traversed by a light flux produced by a light source, this degradation leads to a loss of part of the light flux, a reduction in the maximum intensity expected at the output of the microlens matrix, as well as a distortion of the image projected by the light source and the appearance of uncontrolled light leakage. The present invention aims to remedy at least partially the aforementioned drawbacks by providing an optical component comprising a microlens matrix easily manufactured by injection molding.and adapted to follow a three-dimensional shape of the optical component exhibiting curvature, and in particular double curvature, without significant degradation of the optical surfaces of the microlenses. In particular, the invention makes it possible to avoid modifying a simple and inexpensive machining technique for creating a mold for forming the microlens array on the optical component. To this end, the invention proposes an optical component designed to allow light to pass through its thickness along a principal optical direction, the thickness being delimited by a first and a second face of the optical component, the optical component comprising a microlens array on one of the first or second faces of the optical component, the microlenses of the array being arranged in rows and columns,The microlens array is characterized in that it has at least one sub-array of microlenses satisfying the following conditions: - on each row of N lenses, each microlens of rank i with 1 <i <N présente d’une part un premier bord en saillie, selon la direction optique principale, d’un bord de l’une des microlentilles de rang i-1 ou de rang i+1, le premier bord et ledit bord de l’une des microlentilles de rang i-1 ou de rang i+1 étant reliés par un premier muret situé dans un premier plan parallèle ou sensiblement parallèle à la direction optique principale, et d’autre part un deuxième bord en retrait, selon la direction optique principale, d’un bord de l’autre des microlentilles respectivement de rang i+1 ou de rang i-1,the second edge and said edge of the other of the microlenses of rank i+1 or of rank i-1 being connected by a second wall situated in a second plane parallel or substantially parallel to the principal optical direction; and - on each column of M lenses, each microlens of rank j with 1 <j <M présente d’une part un troisième bord en saillie, selon la direction optique principale, d’un bord de l’une des microlentilles de rang j-1 ou de rang j+1, le troisième bord et ledit bord de l’une des microlentilles de rang j-1 ou de rang j+1 étant reliés par un troisième muret situé dans un troisième plan parallèle ou sensiblement parallèle à la direction optique principale, et d’autre part un quatrième bord en retrait, selon la direction optique principale, d’un bord de l’autre des microlentilles respectivement de rang j+1 ou de rang j-1,The fourth edge and the edge of the other microlens of rank j+1 or rank j-1, respectively, are connected by a fourth boundary located in a fourth plane parallel or substantially parallel to the principal optical direction. The principal optical direction designates the direction of the rays passing through the thickness of the optical component without being deviated; other rays may have acute angles with this direction. The optical component is, for example, capable of diffusing the light passing through it. The microlenses of the microlens array of the optical component according to the invention have optical surfaces with dimensions on the order of a millimeter, for example, from 0.3 to 10 mm on a side, and the rows of the array may be of different lengths, just as the columns of the array may be of different lengths.for example, to follow the shape of the optical output surface of a lighting device according to the invention. By "parallel or substantially parallel" is intended to cover a predominantly parallel orientation that takes into account an angle due to the manufacturing of the part, typically on the order of five degrees at most. In other words, the walls are oriented primarily along the principal optical direction (also along the demolding direction), within a draft angle. Thanks to the invention, the walls are contained in a plane forming an angle of less than five degrees with the principal optical direction, the corresponding risers of a mold used to form the microlens array of the optical component according to the invention being able to be more easily machined according to the characteristics of the microlens array.Consequently, the optical surfaces of the microlenses are not, or only very slightly, degraded. The invention also makes it possible to achieve radii of curvature, resulting from a machining radius, of less than 0.1 mm between the risers and the counterforms intended to form the optical surfaces of the microlenses, on the mold for manufacturing the optical component according to the invention. These advantages are obtained due to the characteristics of the sub-matrix, according to which no microlens of the sub-matrix is ​​directly surrounded by three protruding walls from that microlens and belonging to adjacent microlenses. Preferably, no microlens of the microlens matrix of the optical component according to the invention is directly surrounded by three protruding walls from that microlens and belonging to adjacent microlenses. In the sub-matrix, the edge of a microlens retains the same configuration,namely, protruding or recessed from an edge of an adjacent microlens along the principal optical direction, over the entire principal dimension of that edge in a direction perpendicular to the principal optical direction. In other words, if an edge of a microlens protrudes, or is recessed, from an edge of an adjacent microlens along part of its edge length, that edge of the microlens remains protruding, or is recessed, from the edge of the adjacent microlens along its entire edge length, possibly even coming to the same level along the principal optical direction. This avoids neighboring edges of adjacent microlenses intersecting, as seen in areas 32 of Figure 3. More generally,The first or second face of the optical component may have less curved areas on which two adjacent microlenses of the microlens array have optical surfaces joined without a wall along an identical edge or portion of an identical edge. The optical component may further include one or more of the following features, taken alone or in combination. The sub-array comprises at least three rows of three columns of microlenses, and preferably the sub-array comprises at least 10 rows of 10 microlenses. In one embodiment of the invention, the conditions on the rows and columns of the sub-array are verified on all the rows and columns of the array, respectively. In another embodiment of the invention,The microlens array is formed of microlens sub-arrays exhibiting the characteristics of the invention and connected to each other by other sub-arrays conforming to the characteristics of the invention, except that at least some of the edges that are meant to be protruding or recessed from other edges are in fact common to those other edges; that is, some microlenses in these other sub-arrays do not have a boundary between them. The microlens array of the optical component according to the invention is, for example, a first microlens array formed on the first face of the optical component, the optical component comprising a second microlens array formed on the second face of the optical component. In one embodiment of the invention,The second microlens array satisfies the same conditions on its rows and columns as the first microlens array. The first microlens array is, for example, a light output array, and the second microlens array is a light input array. It should be noted that the second face of the optical component may not have a double curvature and may not require a second microlens array satisfying the same conditions on its rows and columns as the first microlens array. In one embodiment of the invention, each microlens of the first microlens array extends along the principal optical direction through the thickness of the optical component until it meets a microlens of the second microlens array.so as to form an optical channel between the two microlenses. The optical channel is generally in the shape of a right prism with a height parallel to the principal optical direction. In one embodiment of the invention, the microlenses of the first microlens array are concave when viewed from outside the optical component, and the microlenses of the second microlens array are convex when viewed from outside the optical component. The expression "viewed from outside the optical component" refers to an observer located outside the optical component on the side of the face on which said microlenses are located. Thus, due to its convex shape, each microlens of the second microlens array converges the light rays that strike it when the optical component is embedded in a lighting device. Advantageously,The convex shape of the microlenses in the second microlens array is configured so that the light rays converge beyond the corresponding microlens in the first microlens array. This ensures that the rays arriving at the microlens in the second microlens array pass through the corresponding microlens in the first microlens array. This also increases the robustness of the lighting device with respect to tolerances, particularly the positional tolerances of the various elements. The invention further relates to a lighting device for vehicles, comprising one or more light sources, a collimator capable of receiving light emitted by the light source(s), and an optical component according to the invention.adapted to receive light transmitted by the collimator and to be traversed by it along the principal optical direction. The optical component according to the invention takes, for example, the form of an L, the two arms of which each have a distinct curvature, so as, for example, to imitate the curve of a vehicle's headlight. The curvatures of the two arms meet at their junction, forming at least one point of inflection. The light source(s) are preferably light-emitting diodes (LEDs). The lighting device is, for example, adapted to project a beam of lighting of the dipped or main beam type. The invention also relates to a mold for forming, at least in part, an optical component intended to be traversed by light through its thickness along a principal optical direction, the thickness being delimited by a first face and a second face of the optical component.the optical component comprising a microlens array on one of its first or second faces, the mold comprising, on one face, counterforms intended to form each a microlens of the microlens array, and risers connecting at least some of the counterforms together, each riser being intended to form, in the microlens array, a wall parallel to the principal optical direction, the counterforms being arranged in rows and columns on the face of the mold, the mold being characterized in that, in at least a portion of the face of the mold, forming a sub-array of counterforms: - on each row of N counterforms, each counterform of rank i with 1 <i <N présente d’une part un premier bord en retrait d’un bord de l’une des contreformes de rang i+1 ou de rang i-1, le premier bord et ledit bord de l’une des contreformes de rang i+1 ou de rang i-1 étant reliés par une première contremarche,and on the other hand a second edge projecting from one edge of the other of the counterforms respectively of rank i-1 or of rank i+1, the second edge and said edge of the other of the counterforms of rank i-1 or of rank i+1 being connected by a second riser; and - on each column of M counterforms, each counterform of rank j with 1 <j <M présente d’une part un troisième bord en retrait d’un bord de l’une des contreformes de rang j+1 ou de rang j-1, le troisième bord et ledit bord de l’une des contreformes de rang j+1 ou de rang j-1étant reliés par une troisième contremarche, et d’autre part un quatrième bord en saillie d’un bord de l’autre des contreformes respectivement de rang j-1 ou de rang j+1, le quatrième bord et ledit bord de l’autre des contreformes respectivement de rang j-1 ou de rang j+1 étant reliés par une quatrième contremarche. Le moule selon l’invention est par exemple métallique,and exhibits characteristics symmetrical to those of the optical component according to the invention. It constitutes all or part of a mold for manufacturing the optical component according to the invention, and may therefore, in particular, comprise several faces, one having convex counterforms for manufacturing the first microlens array of the optical component, and the other having concave counterforms for manufacturing the second microlens array of the optical component. It offers advantages analogous to those of the optical component according to the invention. Other features and advantages of the invention will become apparent from the following description, on the one hand, and from several illustrative and non-limiting examples given by reference to the accompanying schematic drawings, on the other hand, in which: [Fig. 1] already discussed in relation to the prior art,[Fig. 2] represents a cross-section of a portion of a mold intended to form a microlens matrix, and which must be produced by a machining tool, according to a model determined during tests by the inventors, [Fig. 3] already discussed in relation to the prior art, represents a cross-section of the portion of the mold of Figure 1 as machined by the machining tool, imperfections in the mold being highlighted by dashed lines, [Fig. 4] represents a cross-section of a lighting device according to the invention, in an embodiment of the invention, the lighting device comprising a light source, a collimator and an optical component according to the invention, represented in a simplified manner in this figure, [Fig. 5] is a perspective view of the optical component according to the invention, in the embodiment of Figure 4,the optical component comprising a microlens array on each of its two principal faces, [fig 6] again shows in cross-section the portion of the mold of Figure 2 of prior art, highlighting features that the inventors sought not to reproduce in the invention, [fig 7] shows in cross-section a portion of a mold intended to form a convex microlens array arranged on one of the faces of the optical component of Figure 5, [fig 8] shows in cross-section a portion of a concave microlens array arranged on the other face of the optical component of Figure 5, [fig 9] shows a portion of a microlens array surface modeled by the inventors and on which they determined features not to be reproduced in the invention, and [fig 10] shows a portion of the surface of the microlens array of Figure 8,on which systematic characteristics of this microlens matrix are highlighted. According to an embodiment of the invention shown in Figure 4, a lighting device 100 according to the invention is intended to be installed in a vehicle to perform a low beam or high beam lighting function. The lighting device 100 comprises a light source 5, a collimator 6, and an optical component 1 according to the invention, aligned along an optical axis, which corresponds to a principal optical direction X of light propagation from the light source 5 to the outside of the vehicle. The light source 5 is, for example, formed of one or more light-emitting diodes, capable of emitting light rays 7. The collimator 6 is capable of collecting and configuring these light rays 7 to direct them into a beam of parallel rays towards the optical component 1.parallel to the principal optical direction X. The optical component 1 is a component made of glass or synthetic polymer material having an overall L-shape, as illustrated in Figure 5. Each arm of the L is curved, presenting a distinct center of curvature, so as to follow the curve of a vehicle headlight. Between the two arms of the L, the optical component 1 has an inflection. A first face 10 of the optical component 1, visible from outside the vehicle, is particularly subject to this requirement of following the curve of the vehicle's headlight. Its shape is generally convex but with an inflection at the arms of the L. This first face is an exit surface of the optical component 1 and forms a first microlens array 11 of the optical component according to the invention. A second face 12 of the optical component 1, facing the interior of the vehicle,is opposite the first face 10 with respect to the optical component 1. The second face 12 is an entry surface of the optical component 1 and forms a second microlens array 13 of the optical component according to the invention. In other words, light rays 7 emitted by the light source 5 enter the optical component 1 through said second face 12. It is understood that the first face 10 and the second face 12 define the thickness of the optical component 1, intended to be traversed by the light rays 7 substantially along the principal optical direction X. In this embodiment of the invention, the first microlens array 11 is a concave microlens array and the second microlens array 13 is a convex microlens array, the optical component 1 performing a light diffuser function in order to homogenize the light of the illumination beam projected by the light device 100. Thus, due to its convex shape,Each microlens of the second microlens array 13 converges the light rays 7 arriving at it. Advantageously, the convex shape of the microlenses of the second microlens array 13 is configured so that the light rays converge beyond the corresponding microlens of the first microlens array 11. This ensures that the rays arriving at the microlens of the second microlens array 13 pass through the corresponding microlens of the first microlens array 11. This also increases the robustness of the lighting device with respect to tolerances, particularly the position of the various elements. The first microlens array 11 forms, on the first face 10 of the optical component 1, rows and columns of varying lengths.so as to cover almost entirely the first face 10 of the L-shaped optical component 1. Each microlens of the first microlens array 11 is indexed 11(i,j) with i between 1 and N, N being the number of microlenses on the row containing the microlens 11(i,j), and j between 1 and M, M being the number of microlenses on the column containing the microlens 11(i,j). Similarly, the second microlens array 13 forms rows and columns of varying lengths on the second face 12 of the optical component 1, so as to almost completely cover the second face 12 of the L-shaped optical component 1. Each microlens of the second microlens array 13 is indexed 13(i,j) with i between 1 and N, N being the number of microlenses on the row containing the microlens 13(i,j), and j between 1 and M, M being the number of microlenses on the column containing the microlens 13(i,j).j). It is understood that the microlens 13(i,j) on the entrance surface of the optical component 1 corresponds to the microlens 11(i,j) on the exit surface of the optical component 1. The optical axes of these microlenses 11(i,j) and 13(i,j) coincide and are parallel to the principal optical direction X. Thus, these microlenses 11(i,j) and 13(i,j) form an optical channel that can be indexed (i,j) and that passes through the thickness of the optical component 1. We now describe, in relation to Figures 6 and 7, the differences between the mold 2 of the prior art and a mold 4 used to form the second matrix of microlenses 13. On the mold 2 of the prior art, the first counterform 20 is delimited in the cutting plane by a first plane P0 and a second plane P1, parallel to a demolding direction corresponding to the principal optical direction X. The second recessed counterform 21 is delimited in the cutting plane,by the second plane P1 and a third plane P2 parallel to the demolding direction. As a reminder, each counterform 20, 21, 22 has a first edge corresponding to the first edge of a microlens, and a second edge corresponding to the second edge of a microlens, in the cross-sectional plane of Figures 1, 2, and 6. The first edge of a counterform 21, 22 is located directly opposite the second edge of an adjacent counterform 20, 21, and the second edge of a counterform 20, 21 is located directly opposite an adjacent counterform 21, 22, the term "directly" meaning at a position offset along a line parallel to the principal optical direction. In other words, each first edge or second edge of a counterform is projected or recessed, respectively, from the second edge or first edge of the counterform to which it is directly opposite. It should be noted that in this patent application,The cutting planes are parallel to a row or column of the microlens array or the counterform array under consideration. A first line d0 passes in the cutting plane through a first edge of the second counterform 21, located in the second plane P1, and through a first edge of the first counterform 20, located in the first plane P0. This first line d0 forms a first acute angle θ_1 in the counterclockwise direction with respect to the second plane P1. A second line d1 passes in the cutting plane through the first edge of the second counterform 21, located in the second plane P1, and through a first edge of the third counterform 22, located in the third plane P2. This second line d1 forms a second acute angle θ_2 in the clockwise direction with respect to the third plane P2, and therefore also with respect to the second plane P1 parallel to this third plane P2. We thus have: θ_1*θ_2 < 0. Now, in this mold 2 of the prior art,The inventors encountered a problem with the feasibility of the counterforms according to the desired model. The fact that the second counterform is boxed between the first and second counterforms produces draft angles that reduce the useful optical surfaces of the microlenses to be produced with mold 2. The inventors found that, in order to obtain a mold capable of producing a microlens array with optical surfaces that can be manufactured without significant degradation, the opposite condition must be met, both on the rows of counterforms or microlenses of the mold or corresponding microlens array, and on the columns of counterforms or microlenses of the mold or corresponding microlens array. Such a mold 4 is shown in Figure 7. On this mold, a first counterform 43 is delimited, in the cutting plane, by a first plane P3 and a second plane P4.parallel to the demolding direction. A second counterform 44 on the mold 4 is delimited, in the cutting plane, by the second plane P4 and by a third plane P5 parallel to the demolding direction. The line d3 passing in the cutting plane through a first edge of the second counterform 44, located in the second plane P4, and through a first edge of the first counterform 43, located in the first plane P3, forms a first acute angle θ_4 in the clockwise direction with respect to the second plane P4. Similarly, the line d4 passing in the cutting plane through the first edge of the second counterform 44, located in the second plane P4, and through a first edge of a third counterform 45, located in the third plane P5, forms a second acute angle θ_5 in the clockwise direction with respect to the third plane P5, and therefore also with respect to the second plane P4.parallel to the third plane P5. Therefore, θ_4 * θ_5 > 0. When this condition is met, regardless of the first, second, and third counterforms that follow one another to form microlenses on each row or column of the microlens matrix, then none of these counterforms, nor any of the corresponding optical surfaces, will be surrounded by more than two risers or, respectively, more than two walls of microlenses. This allows for the fabrication of mold 4 with draft angles strictly less than 5 degrees and radii of curvature less than 0.1 mm. Mold 4 is, for example, used to form the second microlens matrix 13, whose microlenses are convex. A mold with convex counterforms satisfying the condition θ_4 * θ_5 > 0 on all series of three counterforms in a row or column of the mold,is usable for producing the first microlens array 11. A microlens array formed by a mold according to the invention, satisfying the condition θ_4 * θ_5 > 0 on all series of three counterforms in a row or column of the mold, has the same characteristics on all series of three microlenses in a row or column of the microlens array. Figure 8 represents the first microlens array 11, formed by a mold according to the invention. In this first matrix 11 of microlenses, a first microlens 11(i-1,j) is delimited in the cutting plane by a first plane P(i-1) and a second plane P(i), parallel to the principal optical direction X. A second microlens 11(i,j) is delimited in the cutting plane by the second plane P(i) and by a third plane P(i+1) parallel to the principal optical direction X. The line d(i-1,j) passing in the cutting plane through a first edge b1(i,j) of the second microlens 11(i,j), located in the second plane P(i), and by a first edge b1(i-1,j) of the first microlens 11(i-1,j), located in the first plane P(i-1,j), forms a first acute angle θ_i in the clockwise direction with respect to the second plane P(i). Similarly, the line d(i,j) passing in the cutting plane through the first edge b1(i,j) of the second microlens 11(i,j), and through a first edge b1(i+1,j) of a third microlens 11(i+1,j), located in the third plane P(i+1), forms a second acute angle θ_i+1 in the clockwise direction with respect to the third plane P(i+1), and therefore also with respect to the second plane P(i), parallel to the third plane P(i+1). We therefore have: θ_i * θ_i+1 >0 This also means that: - the first edge b1(i,j) of the second microlens 11(i,j) is set back from a second edge b2(i-1,j) of the first microlens 11(i-1,j), these two edges being connected by a first wall m_i located in the second plane P(i),and a second edge b2(i,j) of the second microlens 11(i,j) is projecting from the first edge b1(i+1,j) of the third microlens 11 (i+1,j), these last two edges being connected by a second wall m_i+1 in the third plane P(i+1), or - the first edge b1(i,j) of the second microlens 11(i,j) is projecting from the second edge b2(i-1,j) of the first microlens 11(i-1,j) and the second edge b2(i,j) of the second microlens 11(i,j) is recessed from the first edge b1(i+1,j) of the third microlens 11 (i+1,j). In other words, the microlenses form a step-like progression, whether this staircase ascends from the first microlens to the third microlens or descends from the first microlens to the third microlens. In this embodiment according to the invention, this condition is met for every microlens 11(i,j) of the first microlens array 11.on all its rows and similarly on all its columns. In other words, the microlenses of the first microlens array 11 are arranged in a stepped pattern, whether on the columns or on the rows of the microlens array 11, without forming any crenellations. Figure 9 represents the surface of a microlens array 15, used to characterize defects on this microlens array 15. The surface illustrated in Figure 9 is a grazing perspective representation of the array 15, on which several columns of the array 15, extending across this surface along a first transverse direction Y perpendicular to the principal optical direction X, are each represented by a continuous line. The rows of the array 15 are each arranged along a second transverse direction, orthogonal to the first transverse direction Y and to the principal optical direction X.and are each represented solely by the reliefs of the microlenses of the line, superimposed one on top of the other from bottom to top in Figure 9. On this surface, a first, a second, a third and a fourth microlenses 15(i-1,j), 15(i,j), 15(i+1,j) and 15(i+2,j) of the same column follow one another along the first transverse direction Y. Each microlens 15(i,j), 15(i+1,j) and 15(i+2,j) of this column has a first edge located at the right of a second edge of a microlens 15(i-1,j), 15(i,j), 15(i+1,j) which precedes it along the first transverse direction Y, the term "at the right" meaning at a position offset along a line parallel to the principal optical direction. The second microlens 15(i,j) forms a slot between the first microlens 15(i-1,j) and the third microlens 15(i+1,j),being delimited between a first plane P_15(i) and a second plane P_15(i+1) parallel to the principal optical direction X of the matrix 15 of microlenses. The third microlens 15(i+1,j) is embedded between the walls formed by the second microlens 15(i,j) and the fourth microlens 15(i+2,j), the walls being respectively in the second plane P_15(i+1) and in a third plane P_15(i+2) parallel to the principal optical direction X. The second and third microlenses 15(i,j) and 15(i+1,j) therefore exhibit reliefs that do not correspond to the steps of Figure 8. On the second microlens 15(i,j), a segment k(i,j) delimited by the first plane P15_(i) and the second plane P_15(i+1) by connecting the first edge of the second microlens 15(i,j) to the first edge of the third microlens 15(i+1,j), intersects a segment l(i,j) delimited by the first plane P15_(i) and the second plane P_15(i+1) by connecting the second edge of the first microlens 15(i-1,j) to the second edge of the second microlens 15(i,j). Similarly, on the third microlens 15(i+1,j), a segment k(i+1,j) delimited by the second plane P15_(i+1) and the third plane P_15(i+2) by connecting the first edge of the third microlens 15(i+1,j) to the first edge of the fourth microlens 15(i+2,j), intersects a segment l(i+1,j) delimited by the second plane P15_(i+1) and the third plane P_15(i+2) by connecting the second edge of the second microlens 15(i,j) to the second edge of the third microlens 15(i+1,j). The inventors observed that in a microlens array whose manufacture does not degrade the optical surfaces, the opposite condition must be verified, that is, that between two planes delimiting a microlens of the array,The segments connecting the edges of the microlenses of the matrix between these two planes must not intersect in the same cutting plane parallel to one of the rows or columns of the microlens matrix. The same condition must therefore be verified for a mold according to the invention, that is to say, between two planes delimiting a counterform of the mold, the segments connecting the edges of the counterforms of the mold between these two planes must not intersect in the same cutting plane parallel to one of the rows or columns of the counterform matrix of the mold. Figure 10 represents the surface of the first microlens matrix 11 of the optical component according to the invention. This representation is similar to that of Figure 9. On this surface of the first microlens matrix 11, it can be seen that a segment u(i,j) delimited by the second plane P(i) and the third plane (i+1) by connecting the first edge of the second microlens 11(i,j) at the first edge of the third microlens 11(i+1,j), does not intersect a segment v(i,j) delimited by the second plane P(i) and the third plane P(i+1) by connecting the second edge of the first microlens 11(i-1,j) to the second edge of the second microlens 11(i,j). The same characteristic is verified for all microlenses 11(i,j) of the first microlens array 11, that is, by varying i or j along an entire row or column of the first microlens array 11. It should be noted that the conditions on the microlenses stated in relation to Figures 8 and 10 are equivalent. They are verified on at least one sub-array of a microlens array of an optical component according to the invention, and symmetrically on any mold forming such a sub-array, by verifying analogous conditions on the mold's counterforms. Of course,The invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention.

Claims

CLAIMS 1- Optical component (1) intended to be traversed by light through its thickness along a principal optical direction (X), the thickness being delimited by a first face (10) and a second face (12) of the optical component (1), the optical component (1) comprising an array (11) of microlenses (11(i,j)) on one of the first or second faces of the optical component (1), the microlenses (11(i,j)) of the array (11) being arranged in rows and columns, the microlens array (11) being characterized in that it has at least one sub-array of microlenses (11(i,j)) satisfying the following conditions: - on each row of N lenses, each microlens (11(i,j)) of rank i with 1 <i <N présente d’une part un premier bord (b2(i,j)) en saillie, selon la direction optique principale (X), d’un bord (b1(i+1,j)) de l’une des microlentilles (11(i+1,j)) de rang i-1 ou de rang i+1, le premier bord et ledit bord de l’une des microlentilles (11(i+1,j)) of rank i-1 or rank i+1 being connected by a first edge (m_i+1) located in a first plane (P(i+1)) parallel or substantially parallel to the principal optical direction (X), and on the other hand a second edge (b1(i,j)) set back, along the principal optical direction (X), from one edge (b2(i-1,j)) of the other microlenses (11(i-1,j)) of rank i+1 or rank i-1 respectively, the second edge and said edge of the other microlenses (11(i-1,j)) of rank i+1 or rank i-1 being connected by a second edge (m_i) located in a second plane (P(i)) parallel or substantially parallel to the principal optical direction (X); and - on each column of M lenses, each microlens (11(i,j)) of rank j with 1 <j <M présente d’une part un troisième bord en saillie, selon la direction optique principale (X), d’un bord de l’une des microlentilles de rang j-1 ou de rang j+1,the third edge and said edge of one of the microlenses of rank j-1 or of rank j+1 being connected by a third wall located in a third plane parallel or substantially parallel to the principal optical direction (X), and on the other hand a fourth edge set back, along the principal optical direction (X), from one edge of the other of the microlenses respectively of rank j+1 or of, rank j-1, the fourth edge and said edge of the other of the microlenses respectively of rank j+1 or rank j-1 being connected by a fourth wall located in a fourth plane parallel or substantially parallel to the principal optical direction (X). 2- Optical component (1) according to claim 1, wherein the sub-matrix comprises at least 10 rows of 10 microlenses. 3- Optical component (1) according to claim 1 or 2, wherein the conditions on the rows and columns of the sub-matrix are verified on all the rows and respectively columns of the matrix (11). 4- Optical component (1) according to any one of claims 1 to 3, wherein the microlens matrix (11) (11(i,j)) is a first microlens matrix formed on the first face of the optical component (1), the optical component (1) comprising a second microlens matrix (13) (13(i,j)) formed on the second face (12) of the optical component (1).

5. Optical component (1) according to claim 4, wherein the second microlens array (13) (13(i,j)) satisfies the same conditions on its rows and columns as the first microlens array (11) (11(i,j)).

6. Optical component (1) according to claim 4 or 5, wherein the first microlens array (11) (11(i,j)) is a light output array and the second microlens array (13) (13(i,j)) is a light input array. 7- Optical component (1) according to any one of claims 4 to 6, wherein each microlens (11(i,j)) of the first matrix (11) of microlenses extends along the principal optical direction (X) in the thickness of the optical component to a microlens (13(i,j)) of the second matrix (13) of microlenses, so as to form an optical channel between the two microlenses (11(i,j), 13(i,j)).

8. An optical component (1) according to any one of claims 4 to 7, wherein the microlenses (11(i,j)) of the first microlens array (11) are concave when viewed from outside the optical component (1) and the microlenses (13(i,j)) of the second microlens array (13) are convex when viewed from outside the optical component (1).

9. An optical component (1) according to any one of claims 1 to 8, adapted to diffuse light passing through it.

10. A vehicle lighting device (100), comprising one or more light sources (5), a collimator (6) adapted to receive light emitted by the light source(s) (5), and an optical component (1) according to any one of claims 1 to 9.capable of receiving light transmitted by the collimator (6) and of being traversed by it along the principal optical direction (X). 11- Mold (4) intended to form at least in part an optical component (1) intended to be traversed by light through its thickness along a principal optical direction (X), the thickness being delimited by a first face (10) and a second face (12) of the optical component (1), the optical component (1) comprising a microlens array (11) on one of the first or second faces of the optical component (1), the mold (4) comprising on one face, counterforms intended to form each one microlens of the microlens array (11), and risers connecting at least some of the counterforms together, each riser being intended to form in the microlens array (11), a wall parallel to the principal optical direction (X), the counterforms being arranged in rows and columns on the face of the mold,the mold being characterized in that, in at least a portion of the mold face, forming a sub-matrix of counterforms: - on each line of N counterforms, each counterform of rank i with 1 ​riser, and on the other hand a second edge projecting from one edge of the other of the counterforms respectively of rank i+1 or of rank i-1, the second edge and said edge of the other of the counterforms of rank i+1 or of rank i-1 being connected by a second riser; and - on each column of M counterforms, each counterform of rank j with 1 <j <M présente d’une part un troisième bord en retrait d’un bord de l’une des contreformes de rang j-1 ou de rang j+1, le troisième bord et ledit bord de l’une des contreformes de rang j-1 ou de rang j+1étant reliés par une troisième contremarche, et d’autre part un quatrième bord en saillie d’un bord de l’autre des contreformes respectivement de rang j+1 ou de rang j-1, le quatrième bord et ledit bord de l’autre des contreformes respectivement de rang j+1 ou de rang j-1 étant reliés par une quatrième contremarche.

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