Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
  • F21S41/20—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by refractors, transparent cover plates, light guides or filters
  • F21S41/25—Projection lenses
  • F21S41/275—Lens surfaces, e.g. coatings or surface structures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
  • F21S41/20—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by refractors, transparent cover plates, light guides or filters
  • F21S41/25—Projection lenses
  • F21S41/255—Lenses with a front view of circular or truncated circular outline

Definitions

• the invention relates to a lens for a motor vehicle optical module and to a motor vehicle optical module comprising such a lens.
• the optical device of a first vehicle must generate an optical beam having a horizontal cut-off line, mainly located below the horizon line, to avoid dazzling second vehicle drivers. crossing or preceding this first vehicle.
• the optical device with a cover and a lens arranged so as to generate this cutoff line, the cover being able to be formed by a horizontal reflective surface, also called a folder.
• the optical device of a first vehicle In order to perform the road function, the optical device of a first vehicle must generate an optical beam illuminating above the horizon line. To avoid dazzling drivers of second vehicles crossing or preceding the first vehicle, the road beam must be deactivated when the first vehicle crosses or follows second vehicles.
• selective route function allows an optical device to illuminate on both sides of second detected vehicles.
• FIG. 1 represents an Isolux diagram 100 of an optical beam providing this selective route function, that is to say comprising a corresponding shadow zone 102. to a detected vehicle 104 whose sides are illuminated.
• the lighting beam in which the shadow area 102 is generated is obtained by means of a code beam (curves 106 in solid lines) and two complementary beams (dotted curves 108) positioned in the figure 1 on either side of the detected vehicle 104.
• the present invention comprises the observation that, the creation of such a shadow zone 102 causing the creation of vertical cut lines 1 10, the sharpness of these lines of vertical cuts 1 10 must be able to be adjusted differently from the sharpness of the horizontal cut lines 1 12 and 1 14 of the code beam and the complementary beam.
• the criteria for optimizing these cut-off lines determined from real tests appear distinct, namely:
• the present invention relates to a lens for a motor vehicle optical module characterized in that it comprises a series of patterns on an optical surface.
• the invention makes it possible to increase the comfort and safety of driving with a lighting device. including implementing a selective route function. Fact :
• the sharpness of the horizontal cut-off lines can be relatively small in order to avoid annoying alternations of contrasts, or even to limit these contrasts, and secondly
• the sharpness of the vertical cutoff lines can be relatively strong to avoid any risk of dazzling of a driver located in the masked area of the driving beam.
• Another advantage of the invention lies in the simple, static and definitive installation of the patterns at the level of the lens, which makes it possible to provide a lighting device at a reduced cost and complexity compared to devices comprising mobile optical elements.
• the invention also relates to a lens for a motor vehicle optical module comprising a series of patterns on an optical surface of entry or exit of the lens, said patterns extending in a preferred direction. it allows to obtain a diffusion in a privileged plane perpendicular to said privileged direction.
• This makes it possible to use the lens in an optical module generating a beam with at least one vertical cut and at least one horizontal cut, with the lens arranged so that the patterns extend substantially horizontally; in this case, thanks to this lens, the at least one vertical cutoff line will be sharper than the at least one horizontal cutoff line.
• This lens is for example particularly useful for an optical module generating a beam delimited by a vertical cut on one of its sides and by a lower horizontal cutoff.
• the patterns are located only on a central area of the optical surface. This makes it possible to reduce the effects due to the chromatic phenomenon.
• the central zone extends over a width representing between 10 and 40% of the width of the optical surface.
• the central zone extends over a length representing between 30 and 100% of the length of the optical surface.
• the patterns are obtained by a modulation of thickness on the surface of the lens following a regular profile. This is a simpler embodiment to achieve.
• the thickness modulation on the surface of the lens is a waviness, in particular a trigonometric modeling.
• the amplitude of the modulation and the pitch of the modulation are constant.
• the amplitude decreases as a function of the position on the lens; in particular in one embodiment the amplitude of the lens decreases exponentially. This makes it possible to obtain a more homogeneous beam.
• the step can also be constant.
• the entrance surface and the exit surface of the lens are provided with series of patterns.
• the patterns are streaks.
• the lens will be simpler to achieve, especially by molding.
• the patterns extend over a central area of the surface of the lens.
• the lens is a one-piece piece, in particular obtained by molding.
• the patterns extending in a preferred direction are located only on a central zone of the optical surface, the peripheral zones outside this central zone having a exit surface provided with microstructures formed by unevennesses generated on its output surface, said microstructures being arranged to diffuse the rays in all directions.
• This makes it possible to use the lens in an optical module generating a beam with at least one vertical cut and at least one horizontal cut, so that rays transmitted by these microstructures are transmitted in directions passing above and below the horizontal cut line and also to the right and left of the vertical cut. The reduction of sharpness is therefore performed on the horizontal and vertical cuts.
• the central structure of the lens which captures the maximum luminous flux and only reduces the sharpness horizontally, we will always have a beam whose cut will be less marked horizontally than vertically, but the vertical cut will not be too brutal.
• the chromatic properties of the generated beam even though, according to an observation peculiar to the invention, the rays diffused by the central part of a lens are more interesting to diffuse. above the cutoff line as the rays scattered by the periphery of the lens. As a result, the latter exhibit a more marked chromatic (color iridescence) phenomenon and thus less participate in white light scattering.
• the microstructures can be produced according to a method for manufacturing a lens for a motor vehicle lighting module, said method being intended to generate on the exit surface of the peripheral zones of said lens microstructures formed by unevennesses, the process comprising the following steps:
• this same method can be applied to different lenses so as to generate different levels of sharpness cut line specific to each lens.
• it is sufficient to associate a distinct profile of unevenness with each lens to obtain a specific level of sharpness.
• it is sufficient to increase a dimension of the unevenness (depth, height or opening) to increase the diffusion of optical rays in different directions and, consequently, reduce the sharpness of the cut line.
• the method comprises the step of generating the unevenness of the microstructures so that each slope has an axis of symmetry, for example an axis of revolution or an axis of rotation.
• the contour of the drop in a plane perpendicular to the axis of symmetry is circular or elliptical, the latter variant allowing in particular to have a variable profile in different directions so that the diffusion by the microstructures can be adjusted independently according to these different directions.
• the axis of symmetry of each drop is parallel to an axis normal to the exit surface of the lens and / or to an optical axis of the lens at the mesh.
• the profile of each elevation is predetermined according to the distance from its mesh to a central portion of the lens so that at least one same dimension, for example a depth or height and / or an aperture can correspond to a diameter, decreases decreases with this distance.
• the edges of the drop are located in the mesh at the exit surface of the lens.
• the profile of the unevenness is predetermined by means of a mathematical modeling of its surface, typically a modeling polynomial which allows a better control of the cut which in particular makes it possible to limit the offset of the maximum of contrast, even to avoid the creation of a double break.
• the method comprises the step of generating secondary elevations located between different meshes.
• the microstructures are formed by unevennesses, these unevenness being generated on its output surface in accordance with a method of manufacturing said microstructures previously described:
• the unevenness forms a mesh on the exit surface of said lens such that each mesh has similar dimensions
• the unevenness has a profile depending on the position of the mesh on the exit surface of the lens.
• the unevenness can be constituted by recesses, reliefs, or a combination of recesses and reliefs.
• the surface of the unevenness is continuous, so as not to have any jump or discontinuity of these unevennesses.
• the surface of the unevenness is continuously differentiable, so as not to have angular points.
• the invention also relates to an optical module for a motor vehicle provided with means capable of generating a light beam intended to illuminate the road, these means comprising at least one cover and a lens arranged so as to generate at the output of the lens a beam exhibiting minus one vertical cutoff line and at least one horizontal cutoff line, at least one optical input or output surface of the lens comprising a series of patterns arranged to reduce the sharpness of the one or more horizontal cutoff lines relatively the sharpness of the line or lines of vertical cuts.
• said beam comprises a vertical cutoff line and a horizontal cutoff line.
• the lens of the optical module is a lens according to one of the preceding embodiments.
• the lighting module of a motor vehicle comprises a lens according to the invention having an exit surface provided with microstructures formed by unevennesses generated on its exit surface, the unevenness being generated on its surface. output in accordance with a method of manufacturing said microstructures previously described:
• the unevenness forms a mesh on the exit surface of said lens such that each mesh has similar dimensions
• the unevenness has a predetermined profile depending on the position of the mesh on the exit surface of the lens.
• the patterns extend horizontally across the optical surface of the optical lens. This makes it possible to have a diffusion in a vertical plane, this makes it possible to use the lens in an optical module generating a vertical cut beam and a horizontal cutoff, having a vertical cut that is sharper than the horizontal cutoff.
• the patterns are obtained by a thickness modulation at the surface of the lens according to a regular profile obtained from a periodic function of a vertical thickness variation having an amplitude (a) and a pitch ( p) given.
• the patterns are streaks that extend horizontally over an entire central area of the lens surface.
• FIG. 1 is an Isolux diagram of an optical beam performing a selective route function
• FIG. 2 represents a lens according to the invention as well as a detailed view of its surface
• FIG. 3 is a representative diagram of the deviations of light rays implemented in the invention.
• FIGS. 4 and 5 are two Isolux diagrams of a selective route beam transmitted respectively by a lens according to the prior art and by a lens according to the invention
• FIG. 6 illustrates an optical module according to the present invention
• FIG. 7a illustrates an alternative embodiment of the modulations on the lens according to the present invention
• FIG. 7b illustrates the variations of the intensity gradient of the diagram of FIG. 5, obtained with the modulation variant of FIG. 7a
• FIG. 8a illustrates another alternative embodiment of the modulations on the lens according to the present invention, the scales of the X and Z axes being respectively identical to those of the X and Z axes of FIG. 7a,
• FIG. 8b illustrates the variations of the intensity gradient of the diagram of FIG. 5, obtained with the modulation variant of FIG. 8a, the scales of the X and Z axes being respectively identical to those of the X and Z axes of FIG. 7b,
• FIGS. 9 and 10 represent different embodiments of mesh formed on the surface of a lens according to a step of a manufacturing method according to a particular embodiment of the invention
• FIGS. 11 and 12 represent different microstructure profile embodiments formed on the lens
• FIG. 13 shows a variant of the embodiment described in Figure 1 1.
• a lens 200 for a motor vehicle optical module comprising means for generating a light beam for illuminating the road.
• Such means comprise in particular a cover and a lens arranged so as to generate, at the output of the lens 200, a beam having a vertical cutoff line and a horizontal cutoff line as previously described for the implementation of the selective route function. .
• An optical surface 202 of the lens comprises a series 204 of patterns 206 for reducing the sharpness of the horizontal cut lines relative to the sharpness of the vertical cut lines, these patterns 206 extending horizontally preferably in a manner similar to streaks. In the illustrated example, these patterns are streaks.
• the series 204 extends horizontally over a central zone 208 of the optical surface 202 which makes it possible to limit the phenomenon of chromatism.
• This chromaticism is due to the fact that the refraction of the material constituting the lens is not constant according to the wavelength of the light (the blue light being more deviated than the red light). This phenomenon appears in particular for significant deviations of light. Thus, this phenomenon is more important in the high and low parts of the lens than in the center.
• the patterns 206 being placed in the central part comprising the modulation, they vertically diffuse the white light. This white light attenuates the colors generated by the chromatic phenomenon by covering the cut-off color with white light.
• the series 204 of patterns 206 extends mainly horizontally to the surface 202 of the lens 200.
• this illustrated example :
• this width I of the series of patterns may represent between 10 and 40% of the width I 'of the surface 202 of the lens 200.
• this length L is equal to the length L 'of the optical surface 202, 65 mm in this example, this length L being measured between the lateral edges of the optical surface 202 .
• this length L can be limited to 30% of the length L 'of the surface 202 the lens 200.
• this predominantly horizontal extension of the patterns causes a mainly vertical "diffusion" of the light rays.
• the rays included in a horizontal plane 300 or 302 will not be diffused horizontally and will be diffused vertically.
• the rays included in a vertical plane 304 will also not be diffused horizontally and will also be diffused vertically.
• the pattern 206 implemented is obtained from a thickness modulation at the surface 204 of the lens 202 in a regular profile corresponding, for example, to a trigonometric modeling, that is to say with a given amplitude a and pitch p.
• the amplitude a is of the order of 10 micrometers while the pitch p is 1 mm.
• FIGS. 4 and 5 show Isolux diagrams obtained from a lighting device using a lens according to the prior art (smooth surface, FIG. 4) or a lens according to the invention (surface comprising reasons, figure 5).
• the curves of equal intensities are as narrow at the level of the lower cut-off 1 14 as at the level of the vertical cut 1 10.
• the Isolux curves are less narrowed at the level of the lower cut-off 1 14 'than at the level of the vertical cut-off 1 10'. Also, as can be seen in FIGS. 4 and 5, these Isolux curves at the level of the lower cut-off 14 'of the beam obtained with the lens according to the invention are less narrow than the lower cut 1 14 of the beam obtained with a smooth lens.
• the sharpness of the horizontal cut is less than the sharpness of the vertical cut.
• FIG. 6 illustrates an example of optical module 400 according to the present invention comprising a reflector intended to receive a light source, here an LED 408, placed at the first focus of a reflector 402.
• the reflector makes it possible to collect the rays emitted by the LED 408 to return them converging forward at a second focus.
• the module 400 also comprises a cover and a lens 200 according to the invention.
• the cover includes a vertical pan 404 and a horizontal pan 406 and is arranged at this focus, leaving a zone 405 through which the rays pass without meeting the cache.
• the lens 200 is also arranged in front of this focus. This lens and this cover are arranged in such a way that the beam emitted by the module 400 has a vertical cut-off line 1 'and a horizontal cut-off line 1', as illustrated in FIG.
• the profile is regular, corresponding for example to a trigonometric modeling, that is to say with a given amplitude a and pitch p.
• a modulation is represented in FIG. 7a, which represents the modulation on the central part, illustrated at an angle of 20 ° vertically on either side of the optical axis X of the lens 200.
• the The scale along the vertical axis and the optical axis is different: the vertical axis Z is graduated in millimeters, while the optical axis X is graduated in micrometers.
• the constricted isolux curves corresponding to the cut are divided into two groups A and B.
• the first group A corresponds to the light / dark cut with a contrast more marked.
• the second group B corresponds to a marked contrast inside the beam between two zones of different luminous intensity.
• Figure 7b further illustrates this phenomenon of double break.
• the contrast gradient in the beam illustrated in FIG. 5 is illustrated, as a function of the positioning in degrees on the vertical axis V.
• the gradient used corresponds to the following formula:
• l ( V ) is the luminous intensity in the beam at a given height V, the height being measured on the vertical axis V
• (l (V + o , r ) ) is the luminous intensity in the beam at a height corresponding to this given height V increased by 0.1 degree.
• FIG. 7b shows a first gradient peak A corresponding to the first cutoff A and a second peak B of gradient corresponding to the second cutoff B. Between these peaks, the progression of the contrast is constant.
• the second cut inside the beam can create discomfort and breaks the uniformity of the beam.
• a solution is to modulate the undulations as can be seen in Figure 8a.
• the modulation pattern is the same as before except that a decreasing amplitude A is used as a function of the position z on the lens, of the form:
• the amplitude of the modulations can vary from 0 to
• the modulation is limited to the center of the lens 200 as previously described and in particular illustrated in FIGS. 2 and 6.
• the peripheral zones 205 outside this central zone containing the series of ripple-shaped patterns 204 may to be smooth.
• these zones 205 outside this central zone containing the series of corrugated patterns 204 may comprise microstructures forming asperities of this exit surface so that rays transmitted by these microstructures are transmitted in directions that pass above and below the horizontal cut-off line and also to the right and left of the vertical cut-off.
• the reduction of sharpness is therefore performed on the horizontal and vertical cuts.
• patent application FR 2 925 656 discloses such a lens in which the microstructures are presented as hollows and bumps arranged either randomly (sanding) or in the form of a relatively regular network on the surface. output of the lens.
• FIG 9 a first step of a method of manufacturing the microstructures of the peripheral zone 205 of a lens 200 according to the invention, such as the lens illustrated in Figures 1 to 8a.
• a mesh (or network) 1102 is formed on a surface 1100, also called a carrier, corresponding to the exit surface of this lens in the peripheral zones so that each of its meshes 1 106 has similar dimensions.
• meshes have similar dimensions when their surfaces do not differ by a multiplicative factor greater than 10.
• a mesh 1 102 is performed using a Cartesian coordinate system (O, x, y, z) for defining parallel or perpendicular segments by varying the horizontal coordinates (Ox) or vertical (Oz) to the surface 1 104 of the portion of the lens 1 100, that is to say with a zero value along the axis (Oy).
• the mesh 1 102 is presented as a grid where each mesh 1 106 corresponds to a substantially square shaped tile.
• a radial mesh 1202 is being formed by means of polar coordinates using a reference (O, r, a) where O corresponds to a center of the surface of the lens, r the distance (or radius) of a ring of thickness dr located around a center O and cut into patterns delimited, on the one hand, by the borders of the ring and, on the other hand, by two rays forming an angle a.
• O corresponds to a center of the surface of the lens
• r the distance (or radius) of a ring of thickness dr located around a center O and cut into patterns delimited, on the one hand, by the borders of the ring and, on the other hand, by two rays forming an angle a.
• meshes 1206 forming concentric rings vis-à-vis the center O of the lens 200.
• the lens 200 has a three-dimensional curved surface such as a spherical surface, or even a complex shape that does not have a geometric center O.
• the mesh 1 102 or 1202 is then formed by projecting only on the surface 1 100 three-dimensional peripheral zones 205 a mesh 1 102 or 1202, formed as previously described, at the optical path followed by a beam transmitted by the lens. This projection is not performed at the level of the patterns 204 extended in a preferred direction. In other words, once the mesh is designed, the center of the mesh corresponding to the surface of the patterns 204 extended in a preferred direction, is not projected on the surface of the lens. It is for the purposes of building the mesh that we consider the center of the lens.
• the method of manufacturing the lens comprises the step of forming, in each mesh 1 106 or 1206, a microstructure generated by a recess of material, also called sink or cavity, according to a predetermined profile depending on the position of the mesh in the mesh.
• a recess 1 108 may be formed so as to have a symmetry of revolution about a central axis 1 1 14 located, simultaneously, in the center of the contour of the recess 1 108 and the tile 1 106.
• the profiles of the recess 1 108 horizontal 1 10 (x, y) or vertical 1 12 (y, z) are identical.
• the recess 1 108 then has a circular contour in each plane perpendicular to the axis 1 January 14, including at the outlet surface where the edges 1 1 17 of the recess in the mesh are located, these edges 1 1 17 being at the exit surface of the lens (carrier).
• a recess 1 108 ' can also be formed in a rectangular mesh 1 106 'having a symmetry of rotation about the central axis 1 1 14'.
• the profiles of the horizontal recess 1 1 10 '(x, y) or vertical 1 1 12' (y, z) are distinct.
• the recess 1 108 ' has an elliptical contour in each plane perpendicular to the axis 1 1 14.
• the predetermined profile is a function of the distance from the mesh to the center of the lens.
• this profile is also a function of the height of the mesh on the lens.
• the amplitude of the profile increases as one approaches a central line of the lens.
• the present invention is capable of many variants.
• this secondary recess 1508 is tangent to the main recesses 1 108 so as to maintain a symmetry of the occupation of the surface 1 102 by recesses while increasing the area dedicated to these recesses at the carrier.
• This embodiment increases the light diffusion and reduces the sharpness of the beam cutoff.
• the radius of such a microstructure corresponds to the distance between a corner of the pattern and the edge of the circle along the diagonal.
• the profile of the recess can be predetermined by means of a mathematical modeling of its surface, for example a polynomial function which makes it possible to modify coefficients of this polynomial function in order to test different profiles on the same type of lens.
• the present invention is capable of many variants.
• the tiles may be square, rectangular or of any other form making it possible to perform a satisfactory mesh of the surface.
• the elevations have been described as recesses or depressions.
• the same characteristics and the same advantages can be obtained with unevenness in the form of reliefs or bumps.
• the same lens may include these two kinds of unevenness, some of which are bumps, some of which are hollows.
• the present invention is capable of many variants.
• the patterns may have different shapes and be continuous or discontinuous.
• a lens or an optical module can be implemented when a module performs one or more lighting functions such as a code function and / or a route function.
• cut-off lines are generated by the cache and / or the lens of the module or by considering different sources of optical radiation, the light-emitting diodes (or LEDs in English for Emitting Diode) being for example envisaged to achieve the invention.
• the shape and the number of cut lines considered during the implementation of the invention may vary from one application to another.
• the generated beam may have an upper horizontal cut, such that the shadow zone is located below the cutoff line, or a lower horizontal cutoff, such that the shadow zone is located above the line. cut.
• the spatial distribution of the illuminated areas and the shadows may vary from one embodiment of the invention to another.

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• 2012
  • 2012-01-12 FR FR1250329A patent/FR2986621B1/fr not_active Expired - Fee Related
• 2013
  • 2013-01-14 US US14/369,890 patent/US9328888B2/en not_active Expired - Fee Related
  • 2013-01-14 EP EP13700379.4A patent/EP2805102A1/de not_active Withdrawn
  • 2013-01-14 WO PCT/EP2013/050566 patent/WO2013104785A1/fr active Application Filing
  • 2013-01-14 CN CN201380005309.3A patent/CN104040250A/zh active Pending

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