EP1762776A1 - Method for the manufacturing of a module or a vehicle headlamp - Google Patents

Abstract

The procedure for designing a dippable lamp with a lens (La) separated by an air gap from a light source with at least one LED consists of selecting a lens with an output surface (As1) that can be linked by smooth and continuous surfaces with the output surfaces of similar modules. The input surface (Ae1) of the lens is shaped to provide a dipped beam without the use of a mask.

Description

The invention relates to a method of constructing a light projector module giving at least one cut-off beam, for a motor vehicle, of the kind comprising a lens and a light source disposed behind the lens of which it is separated by air, the light source comprising at least one light emitting diode.

Light-emitting diodes, hereinafter abbreviated as "LED" or "diode", deliver relatively limited light flux, of the order of 100 lumens. Also, to achieve lighting functions for a motor vehicle and obtain the necessary luminous flux, it is necessary to use several diodes: for example, for a projector type code, it is common to provide a dozen or more diodes, and as many of modules to a single diode. This results in a pixelated or pointillist aspect of the projector, which is not desired. The outer surface of the projector may have discontinuities in the junction areas of the juxtaposed modules, which is also not desired. The radii of curvature of this outer surface are generally not adapted to those of neighboring body parts, which is not suitable for the style. The fusion of the light beams of the different modules also needs to be improved.

The object of the invention is, in particular, to create a lens light projector module that can be assembled in a continuous manner in an extinct aspect to neighboring modules, and that makes it possible to create controlled light beams without constraint of radius of curvature on the surface. output of the overall part forming the projector. Preferably, the lens module should be able to provide complex forms of beam splitting.

It is also intended to obtain an LED module and lens that is adaptable to provide different types of beam, including beams, or flat or oblique cut beam portions, such as code beams or beams. beams called motorway beams (or "motorway" in English).

According to a first embodiment of the invention, the method of constructing a light projector module for a motor vehicle, of the kind defined above, is such that the exit surface of the lens is chosen so that it can be connected in a smooth and continuous manner with the exit surfaces of similar neighboring modules, and that the entrance surface of the lens is determined so as to obtain the cutoff of the light beam, without using an occulting cover.

In the context of the invention, the term "concealment mask" is understood to mean a mask that intercepts the light that essentially reaches it by absorption (as opposed to a light reflecting element in particular).

Within the scope of the invention, "similar modules" include modules whose external appearance is similar, and which also comprise a lens and at least one light-emitting diode, but which can generate either a cut-off beam or a beam without cutoff (road type).

These similar modules can also be modules as defined above but equipped with at least one light emitting diode emitting essentially in the infra-red and not in the visible, this in particular to allow to emit an infra-red beam. Red uninterrupted road-type distribution for night driving assistance.

According to a second embodiment of the invention, which may be added to the previous one, the subject of the invention is a method of constructing a light projector module giving a cut-off beam, for a motor vehicle, comprising a lens and a light source disposed behind the lens from which it is separated by air, the light source being formed by at least one light emitting diode. The method is such that the exit surface of the lens is chosen and the entrance surface of the lens is determined by relying on a horizontal generatrix, so as to obtain the breaking of the light beam emitted by the module without using an occulting cover, and with a controlled horizontal distribution of said light beam.

Throughout the remainder of the text, the terms "low", "high", "horizontal" and "vertical" are understood as referring to the positioning of the module or the projector in their mounting position in the vehicle.

Preferably, the exit surface of the lens is selected as being substantially cylindrical or toroidal, the section of the exit surface of the lens being a vertical plane parallel to the optical axis being convex forward.

It is possible to choose the curvature (s) of the exit surface of the lens substantially equal to the curvature (s) of the walls surrounding the module.

For the construction of a module comprising an ellipsoidal reflector and a folder, the exit surface is advantageously chosen to be that of a cylinder of revolution whose section by a vertical plane passing through the optical axis is a convex circular arc. forward, and the entrance area is constructed to be stigmatic between the second focus of the ellipsoidal reflector and infinity.

For the construction of a module with diode in direct view of the lens, the output surface is generally chosen toric, vertical axis of revolution, and the input surface is constructed so as to create a horizontal cut.

The invention also relates, according to a first embodiment of the module, to a motor vehicle headlight module comprising a lens and, behind the lens, a light source separated from the lens by air and formed by at least one light-emitting diode, said module being such that the exit surface of the lens is entirely convex towards the front and is such that it can be connected in a smooth and continuous manner with the lens exit surfaces of neighboring modules similar, and the input surface of the lens is defined so that the module gives a light beam cut without intervention of a blackout cover, including vertical.

It is also relative, according to a second embodiment of the module (which may possibly be added to the first) to a light projector module giving a cut-off beam, for a motor vehicle, comprising a lens and a light source arranged behind the lens from which it is separated by air, the light source comprising at least one light-emitting diode, such that the exit surface of the lens is entirely convex towards the front, and the entrance surface (Ae1-Ae5) of the lens is defined by relying on a horizontal generatrix, so that the module gives a light beam cut without intervention of an occulting cover, in particular vertical, and with a horizontal distribution.

According to a variant of this second embodiment, the entrance surface (Ae6) of the lens is calculated in such a way that a family of light rays, called limit radii, emanating from the emitter of the light source, emerge of the lens so that they are all normal, at the points where they meet it, at a surface, called output wave surface, cylindrical, vertical generators and any cross section (the choice of a straight section or more generally, a director of the output wave surface makes it possible to control the horizontal distribution of the energy in the beam and here replaces the choice of the "generating curve" of the preceding variant). The limit radii are chosen so that all the other light rays coming from the source reaching the entrance face of the lens at the same point as they emerge from the exit face (As6) with a direction vector of vertical component negative or zero. In this way, the generated beam has a horizontal cutoff line and all images of the transmitter meet this limit line at infinity at one point. In this second variant (subsequently designated IIβ), the lens input surface is generally discontinuous, the points (called foci) of the emitter from which the limit rays are derived being different depending on the point of emergence of the beam. limit on the surface of the source reaches the entrance face of the lens at a point above or below (along the vertical axis z) of it. It goes without saying that the physical part comprises a continuous surface made up of the above-mentioned high and low surfaces and a connection surface, ideally set, with generatrices parallel to the optical axis, and, in practice, inclined generatrices. relative to this axis so as to allow demolding of the lens.

The advantage of variant IIβ lies in the possibility of calculating the output area (in two parts) directly (one equation for each point, independent of the neighboring points) and not step by step, which causes the propagation of the errors of calculations and possibly numerical oscillations. In addition, the choice of the output wave surface imposes precisely the direction of the highest radius of each image according to its point of emergence at the exit surface of the lens, while the "generating curve" of the preceding variant constitutes only one of the boundary conditions for a system of partial differential equations and, if it makes it possible to control the horizontal distribution of the energy, can not be directly connected to the horizontal position of a image from a given point of the exit surface.

The exit surface of the lens may be cylindrical or toric, the section of the exit surface of the lens by a vertical plane parallel to the optical axis being convex forwards.

The curvature (s) of the exit surface of the lens may be substantially equal to the curvature (s) of the walls surrounding the module on the vehicle.

The light projector module may comprise an ellipsoidal reflector and a folder, in which case the exit surface is advantageously chosen to be that of a cylinder of revolution whose section by a vertical plane passing through the optical axis is an arc of a circle. convex forward, and the entrance surface is constructed to be stigmatic between the second focus of the ellipsoidal reflector and the infinite.

The shape of the edge of the folder may be provided for the beam bright has a V cut.

The edge of the folder may have valley deformation to compensate, in part, for the aberrations of the lens.

The edge of the folder may have on both sides of the vertical plane passing through the optical axis two bumps connected by a portion in bowl to form an additional module for a highway code, strengthening the light in the axis below from the horizontal.

Advantageously, the input surface is such that the optical path is constant from the external focus of the reflector, to a plane tangential to the exit face at its point of intersection with the optical axis of the module.

According to another possibility, the focus of the lens is offset transversely with respect to the optical axis and the module illuminates in a lateral direction with respect to the optical axis, the input surface of the lens being such that the optical path is constant between the focus of the lens and a vertical plane whose trace on the horizontal plane of the optical axis is inclined relative to this axis.

In the case of a module whose light source is in direct view of the lens, the output surface of the lens is selected toric of vertical axis of revolution, and the input surface is defined to give a beam cutoff horizontal. The light source may consist of a rectangular lambertian emitter placed in a vertical plane, orthogonal to the optical axis, or by a light-emitting diode having a transparent protective dome located above the emitter, itself placed in the light source. 'air.

According to a variant of the invention, the module comprises a light-emitting diode in direct view of the lens, said diode being disposed in an oblique plane with respect to the optical axis of said module. In this case, a light-emitting diode is preferably chosen having a transparent protective dome located above the emitter. Thus tilting the diode modifies the shape and distribution of the beam complementary to the code beam emitted by the module: when it is desired to obtain a so-called motorway beam (or "motorway" in English) that is regulatory, one needs a portion of beam that is of high intensity and thin.

With a diode arranged to emit perpendicularly to the lens, it tends indeed to obtain a generally rectangular shaped beam but generally quite "thick" and not very intense. To make the beam less "thick", it would be possible to increase the focal length of the lens, but then the diode / lens distance must be increased, thus increasing the dimensions of the module, which is not always possible and complicated. the integration of the module in the projector.

Another very effective solution for controlling / decreasing the thickness of the beam has therefore been to tilt the diode relative to the lens: they are thus found more completely vis-à-vis one another. Note that this inclination can be chosen at a positive or negative angle with respect to the optical axis, the two types of inclination for adjusting the thickness of the beam in a comparable manner.

Advantageously, the diode is sufficiently inclined so that the angle under which is seen the emitter of the diode from a majority of points (corresponding to at least 75% of the input area for example) of the lens is smaller than what it would be with a lens arranged in a plane perpendicular to the optical axis of the module.

Another favorable condition is to choose the inclination of the diode so that the radius most inclined relative to the axis of the emitter of the diode reaching the lens is lower than the limit angle of the distribution of the light beam emitted by the diode. This prevents a zone of the lens from receiving more light from the transmitter.

An appropriate inclination is for example an angular deviation with respect to the optical axis of the module of the order of +/- 35 ° to +/- 55 °, in particular from +/- 40 ° to +/- 50 °, by example of + 45 ° or - 45 °.

As mentioned above, by tilting the diode, it is easy to obtain with the module a beam or a portion of the motorway-type beam, in particular having a beam thickness of less than 5%, (corresponding to 2.852 °), in particular less than 3% (which corresponds to 1.718 °), a high intensity, in particular at least 40 lux at 25 meters, and a cut above the horizontal part of the cut of the code beam. This cut is clear and is naturally below the glare limit defined in the relevant regulations.

According to another variant, the module may comprise a light source including a light-emitting diode in direct view of the lens, the module being such that, in the mounting position, the emitter of the diode and the lens are inclined both laterally in a vertical plane, in particular to obtain a beam or a portion of obliquely cut light beam.

It is thus understood that the present invention proposes light-emitting diode modules which are in direct view of associated lenses, and in this case there is no reflector or "bender", and light-emitting diode modules which are associated with reflector and folding, besides the lens.

The invention also relates to a light projector giving a cut-off beam, for a motor vehicle, as it is formed by an assembly of several modules as defined above, juxtaposed so that the output surface of the projector optics is smooth, continuous.

The luminous headlight is advantageously constituted by several superimposed rows of assembled modules, some of the modules providing a 15 ° cut, other modules being able to illuminate laterally, each extinguished row having the external appearance of a single cylindrical rod or a continuous ring segment.

The invention also relates to any module assembly, which assembles a plurality of modules, at least one of which provides an oblique cutoff as described above, with other similar modules capable of emitting an unbroken beam and possibly with similar modules. can illuminate laterally. It is thus possible to insert into a projector one or more rows associating dedicated modules code with dedicated road modules in the visible and / or road in the infra-red, keeping an external appearance unit very interesting for the style of the projector in general.

The invention also relates to any unitary module for making a beam or a beam portion with horizontal or oblique cut. If it is intended to emit a beam portion, it may be supplemented by another complementary beam, emitted by a different module and already known, using for example conventional light sources of halogen or xenon type.

• Fig. 1 est une vue schématique en coupe verticale d'un premier mode de réalisation d'un module avec réflecteur ellipsoïdal selon l'invention.
• Fig. 2 est une vue schématique en coupe horizontale selon la ligne II-II de Fig.1.
• Fig.3 est une vue schématique de gauche par rapport à Fig.1 du réflecteur ellipsoïdal du module et de la plieuse.
• Fig.4 est un schéma illustrant, en coupe verticale, la construction de la surface d'entrée de la lentille du module de Fig. 1.
• Fig.5 est une représentation des courbes isolux du faisceau lumineux obtenu avec le module de Fig.1.
• Fig.6 est une vue schématique de face, semblable à Fig.3, du réflecteur ellipsoïdal et de la plieuse d'un module donnant un faisceau de type « motorway lighting » (code pour autoroute).
• Fig.7 est une représentation du réseau de courbes isolux du faisceau obtenu avec le module de Fig.6.
• Fig. 8 est un schéma en plan illustrant une construction de module éclairant dans une direction latérale.
• Fig. 9 est une vue schématique en coupe horizontale d'un module selon Fig.8.
• Fig. 10 représente le réseau de courbes isolux obtenu avec le module de Fig.9.
• Fig.11 est un schéma en perspective illustrant le procédé de construction d'un deuxième mode de réalisation de module selon l'invention dans lequel la source lumineuse éclaire directement la face d'entrée de la lentille.
• Fig.12 est une coupe verticale schématique d'un premier exemple de lentille construite selon Fig. 11.
• Fig.13 représente le réseau de courbes isolux d'un module comportant la lentille de Fig. 12.
• Fig.14 est une coupe verticale schématique d'un autre exemple de lentille construite selon Fig. 11.
• Fig.15 représente le réseau de courbes isolux obtenu avec un module équipé de la lentille de Fig.14.
• Fig.16 est une coupe schématique par un plan vertical d'une diode électroluminescente dont l'émetteur est protégé par un dôme.
• Fig.17 est une coupe schématique par un plan horizontal de la diode de Fig.16.
• Fig.18 est une coupe verticale schématique d'un module selon le deuxième mode de réalisation avec une diode éclairant directement la face d'entrée d'une lentille.
• Fig.19 représente le réseau de courbes Isolux obtenu avec le module de Fig.18.
• Fig.20 est une coupe schématique horizontale d'un assemblage de plusieurs modules selon l'invention, et
• Fig.21 est une vue schématique de face d'un projecteur avec assemblages superposés de modules.
• Fig.22a, 22b est une vue schématique en perspective de deux modules adjacents selon l'invention, Fig.22a avec des diodes disposées perpendiculairement à l'axe optique des modules, Fig.22b avec des diodes inclinées par rapport à l'axe optique des modules,
• Fig.23a,23b sont des réseaux de courbes isolux obtenus avec les modules selon les figures 22a et 22b.
• Fig.24a,24b concernent une variante de réalisation, avec une vue de la diode et de la lentille et les courbes d'isolux correspondantes en vue de l'obtention d'un faisceau de type anti brouillard.
• Fig.25a,25b concernent une variante de réalisation, avec une vue de la diode et de la lentille et les courbes d'isolux correspondantes en vue de l'obtention d'un faisceau de type autoroute (« motorway »).
• Fig.26 concerne une représentation d'une diode permettant d'illustrer une méthode de construction de surface explicitée plus loin.

The invention consists, apart from the arrangements described above, in a certain number of other arrangements which will be more explicitly discussed hereinafter with regard to exemplary embodiments described with reference to the appended drawings, but which are not in no way limiting. On these drawings:

• Fig. 1 is a schematic vertical sectional view of a first embodiment of a module with an ellipsoidal reflector according to the invention.
• Fig. 2 is a schematic view in horizontal section along the line II-II of Fig.1.
• Fig.3 is a left schematic view with respect to Fig.1 of the ellipsoidal reflector of the module and the folder.
• FIG. 4 is a diagram illustrating, in vertical section, the construction of the entrance surface of the lens of the module of FIG. 1.
• Fig.5 is a representation of the isolux curves of the light beam obtained with the module of Fig.1.
• FIG. 6 is a diagrammatic front view, similar to FIG. 3, of the ellipsoidal reflector and the folder of a module giving a beam of the "motorway lighting" type.
• FIG. 7 is a representation of the network of isolux curves of the beam obtained with the module of FIG.
• Fig. 8 is a plan diagram illustrating a module construction illuminating in a lateral direction.
• Fig. 9 is a schematic view in horizontal section of a module according to FIG.
• Fig. 10 represents the network of isolux curves obtained with the module of FIG.
• Fig.11 is a perspective diagram illustrating the method of constructing a second module embodiment according to the invention wherein the light source directly illuminates the input face of the lens.
• Fig.12 is a schematic vertical section of a first example of a lens constructed according to Figs. 11.
• FIG. 13 represents the network of isolux curves of a module comprising the lens of FIG. 12.
• Fig.14 is a schematic vertical section of another example of a lens constructed according to Figs. 11.
• FIG. 15 represents the network of isolux curves obtained with a module equipped with the lens of FIG.
• Fig.16 is a schematic section through a vertical plane of a light-emitting diode whose emitter is protected by a dome.
• Fig.17 is a schematic section through a horizontal plane of the diode of Fig.16.
• Fig.18 is a schematic vertical section of a module according to the second embodiment with a diode directly illuminating the input face of a lens.
• Fig.19 shows the network of Isolux curves obtained with the module of Fig.18.
• Fig.20 is a schematic horizontal section of an assembly of several modules according to the invention, and
• Fig.21 is a schematic front view of a projector with superposed assemblies of modules.
• Fig.22a, 22b is a schematic perspective view of two adjacent modules according to the invention, Fig.22a with diodes arranged perpendicular to the optical axis of the modules, Fig.22b with diodes inclined with respect to the optical axis modules,
• Fig.23a, 23b are networks of isolux curves obtained with the modules according to Figures 22a and 22b.
• Fig.24a, 24b relate to an alternative embodiment, with a view of the diode and the lens and the corresponding isolux curves for obtaining an anti-fog type beam.
• Fig.25a, 25b relate to an alternative embodiment, with a view of the diode and the lens and the corresponding isolux curves for obtaining a motorway-type beam ("motorway").
• Fig.26 relates to a representation of a diode for illustrating a method of surface construction explained later.

Referring to the drawings, especially Figs. 1 and 2, Figs. 9, FIGS. 12 and 14, FIG. 18 shows, diagrammatically, a light projector module for a motor vehicle comprising a lens La, Lb, Lc, Ld, Le and a light source formed by at least one light-emitting diode Da , Db, Dc, Dd, De arranged behind the lens. An air space separates the diode from the lens.

In the description and claims, the terms "forward" and "backward" are to be considered in the direction of propagation of the luminous flux from the source to the lens, and the module is to be considered in the position it occupies on the vehicle, ie with its horizontal optical axis.

According to the invention, in order to construct the light projector module, the procedure is as follows.

The output area As1, As2, As3, As4, As5 of the lens La, Lb, Lc, Ld, Le is chosen so that it can be connected in a smooth, continuous surface with the exit surfaces of adjacent modules. Similar. This output surface is further selected to have a curvature adapted, preferably substantially equal to that walls W (Fig.1) surrounding it, including the walls of the vehicle body. The exit surface is fully convex forward.

The entrance surface Ae1, Ae2, Ae3, Ae4, Ae5 of the lens is determined so as to obtain, without a vertical cover, a light beam with cutoff with spreading of the light.

• une portion de surface cylindrique de révolution dont les génératrices sont horizontales, orthogonales à l'axe optique du module,
• ou une portion de surface torique d'axe de révolution vertical.

Preferably, the exit surface As1-As5 of the lens is chosen to be:

• a portion of cylindrical surface of revolution whose generatrices are horizontal, orthogonal to the optical axis of the module,
• or a portion of toric surface of vertical axis of revolution.

The case of the cylindrical surface can be considered as the case particular of a toric surface whose axis of revolution is at infinity.

The exit surface of the lens has a horizontal plane of symmetry passing through the optical axis of the module; the section of the exit surface, cylindrical or toric, by a vertical plane passing the optical axis is a forward convex circular arc.

The radii of curvature in a horizontal plane and in a vertical plane of the exit surface of the lens are freely chosen to match the curvatures of the walls W surrounding the module.

Two modes of construction of the module are provided.

According to a first mode, corresponding to FIGS. 1 to 10, the module comprises an ellipsoidal reflector Ma, Mb having two foci namely an internal focus in the vicinity of which is placed the light source and an external focus coincides with the focus of the lens or neighboring this focus. The light source does not directly illuminate the input face of the lens, but illuminates towards the reflector, substantially at right angles to the optical axis of the module. A folder Na, Nb is located in the horizontal plane passing through or near the optical axis of the module. The front edge of the folder goes through the focus of the lens.

According to another embodiment, corresponding to FIGS. 11 to 19, the light source is in direct view of the entrance face of the lens, without the intervention of a reflector or a folder.

These embodiments will be described successively.

1. Module with ellipsoidal reflector and folder.

Referring to Figs. 1 and 2, we can see a projector Ea having a light source consisting of at least one LED Da whose maximum emission point is preferably located at the internal focus Bi of the ellipsoidal reflector Ma. The external focus Be is located in before Bi. The reflector Ma corresponds substantially to the upper rear quarter of an ellipsoid of revolution whose geometric axis coincides with the optical axis Oy of the module and the lens La, located in front of the external focus Be.

To locate points in space, we use a reference trirectangular trihedron whose axis Oy corresponds to the optical axis of the module, the axis Ox is orthogonal to Oy in the horizontal plane, and the axis Oz is vertical .

The diode Da is oriented so as to illuminate substantially upwards, substantially at right angles to the optical axis Oy, towards the reflector Ma. The rays from Bi are reflected to converge towards the focus Be confused with the focus of the lens.

The module further comprises a folder Na, that is to say a plate whose upper surface is reflective, located in a horizontal plane passing through the optical axis Oy and whose front edge 10 passes through the focus Be, and determines the cutoff line of the light beam. The illumination is below the image of this edge given by the lens La.

The outlet area As1 is chosen so that it can be connected in a smooth, continuous surface with adjacent similar module exit surfaces, while having a curvature adapted to the surrounding walls W.

The entrance surface Ae1 of the lens is determined so as to obtain a light beam with cut-off of the light. The surface Ae1 is constructed to be stigmatic between the second focus Be of the reflector Ma and the infinite.

In other words, as illustrated in FIG. 4, Ae1 is such that a light ray r1 coming from the focus Be and propagating in the air, after entering the lens La and refraction along r2, leaves the surface As1 along a radius r3 parallel to the optical axis Oy The optical path is constant between the focus Be and a plane II1 tangential to the output face As1 at its intersection point h1 with the optical axis of the module.

In the case of Figs. 1, 2 and 4, the exit surface As1 is chosen to be that of a cylinder of revolution of horizontal geometric axis, orthogonal to the optical axis. (It could also be of substantially toric shape). The section of the surface As1 by the vertical plane of FIG. 4 is an arc having its center at the point ω situated on the optical axis Oy, in front of the external focus Be, the generatrices being perpendicular to the plane of FIG. . The three-dimensional construction is then done in all vertical planes parallel to the Oyz optical axis.

We denote by P the current point of the input surface Ae1, by Q the exit point of the radius r2, by U the point of entry of the ray along the optical axis, and by K the intersection with the plane Π1 of the parallel to the optical axis passing through the point Q. By n denoting the refractive index of the lens material, the constancy of the optical path from the external focus Be to the plane IZ1 is expressed by: $$\mathrm{BeP}+\left(\mathrm{not}\mathrm{.}\mathrm{PQ}\right)+\mathrm{QK}=\mathrm{constant}=\mathrm{Beu}+\left(\mathrm{not}\mathrm{.}\mathrm{Uh}1\right)$$

In the three-dimensional construction, according to the other planes, w, P, Q, r2 and r3 remain identical to those represented in FIG. 4. On the other hand, O and r1 are then points of space which no longer belong to the cutting plane according to Figure 4.

By juxtaposing modules in the direction of the generatrices of the exit surface As1 a bar is obtained whose outer surface is cylindrical, smooth and continuous.

Several LEDs may be arranged parallel to the generatrices of the exit surface. The successive front edges 10 of the folders of the different modules are aligned parallel to the generatrices of the cylindrical surface As1.

It is possible to make a V cut especially with a left horizontal branch and a branch rising at an angle of 15 ° right (European code) by providing an appropriate edge of the folder. The cutoff lines of the various modules are aligned which is found at the level of the image on a screen. Fig. 5 gives the diagram of the isolux curves obtained with a module as defined above.

A lens with a cylindrical exit surface As1 has aberrations that can be compensated, in part, by a modification of the shape of the edge of the folder 10 by providing a bump-shaped deformation 11 (FIG. in a vertical plane. Fig. 3 illustrates a form of folder with a branch rising substantially straight to the right, and a branch with slope break on the left.

By changing the shape of the folder and its edge through the focus Be, while taking into account aberrations, it is possible to create other types of light beams.

For example, according to FIG. 6, the edge 10a of the folder has on both sides of the vertical plane 12 passing through the optical axis two bumps 13,14 connected by a portion 15 in a bowl. The bumps 13,14 extend on both sides by 16,17 depression areas that go back to reach the edge located in the horizontal plane passing through the optical axis.

Such a module can constitute an additional module for a motorway lighting code which makes it possible to reinforce the light in the axis, below the horizontal.

Fig. 7 illustrates the isolux network obtained with the module of FIG. 6 which has a maximum of intensity in the axis, the isolux curves being located below the horizontal intersecting the optical axis, being substantially symmetrical with respect to the vertical plane passing through the optical axis.

For the composition of a complete light beam, obtained from the light beams produced by each of the modules of a headlamp, one or more modules are advantageously provided with an output face identical to that of the modules giving a cutoff at "15 ° "(Fig.5), but illuminating in a lateral direction to complete the beam with light under the cut, eg left for right-hand drive country vehicles.

For this purpose, according to FIG. 8, a module is constructed having a stigmatic lens Lb between a focus point 18, abscissa x _F and a vertical plane wave, inclined with respect to the optical axis and whose trace 19 on the plane horizontal is represented. The inclination of the plane wave is intended to promote lighting under the cutoff, on the left. The focal point 18 of the lens Lb is shifted to the right with respect to the straight line Oy passing through the center of the exit face As2. The exit surface As2 of the lens is chosen cylindrical of revolution; its horizontal section on Fig.8 and 9 is a rectilinear generator. The entrance surface Ae2 of the lens is constructed so that the optical path between the focus 18 and the vertical trace plane 19 is constant.

The lens Lb, a horizontal section of which is visible in FIG. 9, is asymmetrical at its entry surface Ae2. From a point G, corresponding to a maximum thickness, situated to the right of the optical axis Oy of the reflector Mb, the lens Lb decreases in thickness to the left less rapidly than to the right.

The isolux network obtained with a projector according to the scheme of FIG. 9 is illustrated in Fig.10. The Isolux curves are located below the horizontal passing through the optical axis, and essentially to the left of the vertical plane passing through the optical axis.

This result is obtained with a module whose output face is similar to that of the modules giving a cut at 15 °. The output faces of the different modules can thus be connected continuously to give a smooth overall surface seen from the front.

II. Module with diode in direct view of the lens II.a Rectangular transmitter in a vertical plane

For the construction of the module, the light source Dc (FIG. 11) is considered to consist of a rectangular lambertian emitter placed in a vertical plane, orthogonal to the optical axis, behind a known primary optics, imposed by the manufacturer of the light emitting diode.

The exit surface As3 (Fig. 12) or As4 (Fig. 14) of the lens is chosen and the entrance surface Ae3 or Ae4 is constructed to create a horizontal cut for given deviations in plan view. Practically we choose surfaces for As3 or As4 surfaces toric vertical axis of revolution, while the primary optics of the light source Dc consists of a single plane, which corresponds to the case of a lambertian transmitter immersed in a resin, behind a planar exit face.

As illustrated in FIG. 11, to construct the entrance surface Ae3 we consider an unknown point M, x, y, z coordinates of the desired surface. We assume that x and z are known and unknown (mesh in Cartesian coordinates, in rear view).

For a plane rectangular light source Dc, located in the air and without primary optics, the input surface is constructed at the point M so that the rays coming from the source Dc and passing through M are falling, or more horizontal, at the exit of the lens Lc. For this, we take into account a limit radius from the source Dc and which, arriving at the point M, has the highest rising inclination. The input surface element in M is constructed so that the ray emerging from the lens, resulting from this limit radius, is straightened horizontally. Under these conditions, all the other rays coming from the source Dc, which arrive at M with a lower inclination, will come out of the lens while being descendants.

The point F of the transmitter in FIG. 11 located the lowest and closest to the plane parallel to the plane (Oyz) passing through M, if M is located in the zone where z is greater than 0, and the furthest of that plane if M is situated in the zone where z is less than 0 ,. is the one that will give the highest inclined radius reaching M, that is to say the limit radius. (In the case where M is located in the zone where z is negative it is possible, to simplify the construction, to use an approximate construction of choosing the symmetric with respect to (Oyz) of the nearest point of the cited plane. ) In the case where an output optic intervenes on the light source, which in practice corresponds to all the cases, it is necessary to take it into account and to consider the point of exit Fs on this optics and not on the transmitter. In the case where the output optics is constituted by a single plane, at a short distance from the transmitter, the choice of the point F indicated above remains acceptable. The output point Fs is determined on the output plane in order to deduce the direction of the limit ray in M. The final condition is established for a given point M of the input surface (horizontality of the limit radius in M when it emerges from the output toric surface) analytically as a function of a single unknown (y), design parameters and two very closely related points already known M1 and M2.

The search for a point close to two known points can be done efficiently and precisely: it boils down to solving an equation non-linear to a single unknown

The construction relies on two boundary conditions defined by the cuts of the surface to be constructed by the planes z = 0 and x = 0. The first section of the surface by the plane z = 0 is arbitrary and constitutes the control parameter the horizontal distribution of light. Advantageously, it is possible to link the horizontal deflection of the light rays originating from the origin of the reference and contained in the plane z = 0 to the abscissa of their intersection with the input surface of the lens. A first case is illustrated in Figure 12, with a deviation independent of the abscissa x and zero. A second case is illustrated in Figure 14, with a non-constant and piecewise linear deviation.

The second boundary condition corresponds to the section through the plane x = 0, that is, the vertical plane passing through the optical axis. The curve corresponding to this section is constructed according to the method previously described so that all the outgoing rays are descending or at most horizontal. In these conditions, it is sufficient to know a single neighboring point to build a new point of the curve. Indeed, the left / right symmetry of the desired beam and the emitter implies that the normals to the surfaces along the sections passing through x = 0 are contained in this same plane. This cut by x = 0 can be constructed point by point by means of the datum of an initial point, advantageously formed by the intersection of the surface with the y-axis. This point is also the initial condition for the z = 0 plane cut and is determined by the thickness at the center of the lens.

Fig. 12 and 14 schematically represent the sections by a vertical plane passing through the optical axis of two lenses of a module according to the invention, for which the exit surface As3 and As4 is a toric surface, with a radius of revolution R = 300mm and a radius of curvature of the section r = 50mm.

In FIG. 12, The module is focused. The input face Ae3 is symmetrical with respect to the optical axis and has a convex vertex facing towards the source with a relatively strong curvature which decreases when one deviates from the optical axis.

Fig. 13 illustrates the network of isolux curves obtained with a module according to Fig.12. The light beam has a horizontal cut-off line in the plane of the optical axis and is substantially symmetrical with respect to the vertical plane passing through this optical axis. The beam has a maximum of illumination in its central zone corresponding to the focus.

FIG. 14 is a diagrammatic vertical section similar to that of FIG. 12, of a module with a light source Dd, which corresponds to a vertical wafer, orthogonal to the optical axis, with several electroluminescent chips aligned along the x-axis.

Figures 12 and 14 use the same light source, Figures 13 and 15 are different because they choose different boundary conditions in z = 0.

The exit face As4 of the lens Ld is toric, identical to the exit face As3 of Fig.12. On the other hand, the input face Ae4 is less convex towards the light source and the thickness of the lens along the optical axis is smaller.

Fig. 15 illustrates the network of isolux curves obtained with the module of FIG. 14. The cutoff line is always horizontal at the optical axis. The isolux curves are substantially symmetrical with respect to the vertical plane passing through the optical axis. The light is more spread out than in the case of the curves of FIG. 13.

II.b - Case of diodes with protective domes

Referring to Figs. 16 and 17, one can see a light source De constituted by an LED having a transparent protective dome 21 located above the emitter 22, itself placed in the air. The inner face 21a and the outer face 21b of the dome 21, or protective bell, constitute two spherical diopters between the air and the transparent material of the dome 21. The successive deviations of the rays due to these two spherical diopters are to be taken into account. This is due, on the one hand, to the low value of the diameters of the spherical diopters which are of the same order of magnitude as the large size of the emitter, and on the other hand to the relatively large thickness of the dome 21, for example approximately 0.5 mm, which is of the same order of magnitude as the small size of the source 22.

The method is as follows: for M given, we search for Fs closest to M in projection on Ox (the farthest for z negative, or the symmetric of the quoted point for z positive, within the framework of a simplified construction) such that there exists a point F of the lower edge of the emitter emitting a ray reaching M and passing through Fs: the corresponding emergent radius in Fs is the limit radius for M.

It will be noted that the spheres 21a, 21b are centered on the center of the emitter 22 and not on its lower edge where the foci F must be taken. As a result, the height of the light source 22 is to be taken into account in the construction of the Ae5 surface.

Fig. 18 is a schematic vertical section of a module with a diode protected by a dome 21 constructed as set forth above. The exit surface As5 of the lens Le is constituted by a freely chosen ring surface, for example having a radius of revolution R = 300 mm and a radius of curvature r = 50 mm. The input surface Ae5 has a convexity facing the light source De and is symmetrical with respect to the vertical plane passing through the optical axis.

Fig.19 illustrates the network of isolux curves obtained with a module according to Fig.18. The curves are located below the horizontal plane passing through the optical axis. Each curve has a substantially rectangular curvilinear contour whose long sides are substantially horizontal, with a slight concavity turned downwards.

Fig.20 illustrates schematically in horizontal section a projector formed by the assembly of three modules whose output surfaces are constituted by cylindrical surfaces of revolution of the same radius of curvature. The input surfaces, located inside the projector form successive corrugations 23 while the output surface is smooth continuous, formed by a cylindrical surface of which a generator 24 appears in Fig.20.

Fig.21 is a schematic front view of a projector with several superposed rows of assembled modules. The upper row 25 corresponds to two modules ensuring a cut at 15 °. The middle row 26 corresponds to three modules, two of which give a cut at 15 ° and the third lights to the left. The lower row 27 corresponds to three modules illuminating to the right. Each extinguished row has the same exterior appearance of a single cylindrical bar or continuous ring segment.

II.c - Case of diodes with protective domes: construction variant

A variant of construction has also been provided in the case of modules, operating in particular but not exclusively with protective diodes with domes as shown in Figures 22a and 22b. Take the case of a module as shown in Figure 22a, with a protective dome diode as described above and arranged vis-à-vis the lens and perpendicular to the optical axis.

à cette surface en M₁ . On suppose également connu un point voisin M₀ et on cherche un nouveau point M de la surface (par exemple, $M=\left[\begin{array}{c}{x}_{M_0+}\delta \begin{array}{}\end{array}x\\ y\\ z_{M_0}\end{array}\right]$

), où delta x et delta z sont les pas d'un maillage en vue arrière de la surface, en coordonnées cartésiennes.
En écrivant que on détermine facilement y, d'où M : $y=-\frac{n_{1_z}}{n_{1_y}}\delta \begin{array}{}\end{array}z+y_{M_1}\mathrm{.}$

The method of construction of the input face of the lens is a little different from that described above: It is considered known a point M ₁ of the entrance surface of the lens and the normal ${\overrightarrow{\mathrm{not}}}_1$

at this surface in M ₁ . We also assume a neighbor point M ₀ and look for a new point M of the surface (for example, $M=\left[\begin{array}{c}{\mathrm{<figure-callout\; id="0"\; label="x\; M"\; filenames="imgf0002.png"\; state="\{\{state\}\}">x\; </figure-callout>}}_{M_{}}\delta \begin{array}{}\end{array}x\\ \mathrm{there}\\ z_{M_0}\end{array}\right]$

), where delta x and delta z are the steps of a mesh in rear view of the surface, in Cartesian coordinates.
In writing that one easily determines y, from where M : $\mathrm{there}=-\frac{{\mathrm{not}}_{1_z}}{{\mathrm{not}}_{1_{\mathrm{there}}}}\delta \begin{array}{}\end{array}z+{\mathrm{there}}_{M_1}\mathrm{.}$

en M.In order to be able to calculate the entire surface step by step, it is sufficient to determine the normal $\overrightarrow{\mathrm{not}}$

in M.

Comme $\Vert \overrightarrow{n}\Vert =1\iff n_x^2+n_y^2+n_z^2=1,$

avec n_y ≥ 0, on en déduit que $n_x=-\frac{y-y_0}{\delta \begin{array}{}\end{array}x}{n}_y$

et $n_y=\sqrt{\frac{1-n_z^2}{1+{\left(\frac{y-y_0}{\delta \begin{array}{}\end{array}x}\right)}^2}}\mathrm{.}$

For this, we first write that $\overrightarrow{{\mathrm{<figure-callout\; id="0"\; label="M"\; filenames="imgf0002.png"\; state="\{\{state\}\}">M</figure-callout>}}_{0}M}\cdot \overrightarrow{\mathrm{not}}=0$

As $\Vert \overrightarrow{\mathrm{not}}\Vert =1\iff {\mathrm{not}}_x^2+{\mathrm{not}}_{\mathrm{there}}^2+{\mathrm{not}}_z^2=1,$

with n _y ≥ 0, we deduce that ${\mathrm{not}}_x=-\frac{\mathrm{there}-{\mathrm{there}}_0}{\delta \begin{array}{}\end{array}x}{\mathrm{not}}_{\mathrm{there}}$

and ${\mathrm{not}}_{\mathrm{there}}=\sqrt{\frac{1-{\mathrm{not}}_z^2}{1+{\left(\frac{\mathrm{there}-{\mathrm{there}}_0}{\delta \begin{array}{}\end{array}x}\right)}^2}}\mathrm{.}$

le vecteur directeur du rayon limite atteignant la surface en M, (c'est-à-dire le rayon issu de la source atteignant M qui doit être dévié par la lentille de façon à en émerger parallèle au plan $\left(O,,\overrightarrow{x},,\overrightarrow{y}\right),$

de sorte que tous les autres rayons issus de la source atteignant la lentille en M soient déviés vers le bas), on calcule facilement la direction $\overrightarrow{r}$

du rayon correspondant, réfracté en M par la surface recherchée, en fonction de $\overrightarrow{n},$

c'est à dire de n_z et de ${\overrightarrow{v}}_o\cdot$

Il est alors facile de calculer le point d'émergence P de ce rayon hors de la lentille en fonction de n_z et ${\overrightarrow{v}}_o$

: on cherche λ tel que P+λ· $\overrightarrow{r}$

appartienne au tore de la surface de sortie. La normale en P étant connue (tore), on calcule finalement la direction $\overrightarrow{e}$

du rayon émergeant, réfracté en P, en fonction de n_z .Is ${\overrightarrow{v}}_o$

the direction vector of the limit ray reaching the surface at M , (that is, the radius from the source reaching M which must be deflected by the lens so as to emerge parallel to the plane $\left(O,,\overrightarrow{x},,\overrightarrow{\mathrm{there}}\right),$

so that all the other rays coming from the source reaching the lens in M are deflected downwards), the direction is easily calculated $\overrightarrow{r}$

corresponding radius, refracted in M by the desired surface, as a function of $\overrightarrow{\mathrm{not}},$

that is to say of n _z and ${\overrightarrow{v}}_o\cdot$

It is then easy to calculate the emergence point P of this radius out of the lens as a function of n _z and ${\overrightarrow{v}}_o$

: we search λ such that P + λ · $\overrightarrow{r}$

belongs to the torus of the exit surface. The normal P being known (torus), we finally calculate the direction $\overrightarrow{e}$

emerging ray, refracted at P , as a function of n _z .

étant connu) une équation analytique à une seule inconnue (n_z ) qui peut être résolue numériquement de manière fiable.
Détermination de $\overrightarrow{v_o}$

:
$\overrightarrow{v_o}=\frac{\overrightarrow{F_{s}M}}{F_{s}M},$

où F_s est le point d'émergence du rayon limite hors du dôme sphérique de protection.We then write that e _z = 0, which is ( $\overrightarrow{v_o}$

being known) an analytic equation with a single unknown ( n _z ) that can be numerically solved reliably.
Determination of $\overrightarrow{v_o}$

:
$\overrightarrow{v_o}=\frac{\overrightarrow{F_{s}M}}{F_{s}M},$

where F _s is the point of emergence of the limit radius outside the spherical dome of protection.

à travers le dôme (d'indice de réfraction connu et supposé sphérique, centré sur l'origine du repère) en appliquant les lois de Descartes de la réfraction (la normale au dôme en $F_s\mathrm{est}\frac{\overrightarrow{{\mathit{OF}}_s}}{r_2}$

). Soit $\overrightarrow{r}ʹ$

la direction du rayon réfracté trouvée, on cherche µ tel que ${\mathit{F}}_s^{ʹ}=F_s+\mu \cdot \overrightarrow{r}ʹ$

appartienne à la surface intérieure du dôme (sphère de rayon r₁ ). Il s'agit d'une équation polynomiale de degré 2, de solution évidemment analytique. On peut alors calculer la direction $\overrightarrow{i}$

du rayon émergent en ${\mathit{F}}_s^{ʹ}$

(la normale au dôme en ${\mathit{F}}_{\mathit{s}}^{\prime }\mathrm{étant}\frac{\overrightarrow{{\mathit{OF}}_s^{ʹ}}}{r_1}$

). On calcule alors l'intersection F de la droite $\left({\mathit{F}}_s^{ʹ},,\overrightarrow{i}\right)$

avec le plan (incliné) de l'émetteur.
F_s est bien choisi lorsque F appartient au bord inférieur de l'émetteur (1^ère équation) et lorsque (2^nde équation) |x-x_Fs | est:

• Pour la partie supérieure de la lentille : minimum
• Pour la partie inférieure de la lentille : maximum (ce qui revient à prendre pour F le coin inférieur de l'émetteur, du côté opposé latéralement à M par rapport au plan $\left(O,,\overrightarrow{y},,\overrightarrow{z}\right)$
  
  ).

Suppose F _s known: we propagate a radius $\left(F_s,-{\overrightarrow{v}}_o\right)$

through the dome (of known refractive index and supposed spherical, centered on the origin of the reference) by applying the laws of Descartes of refraction (the normal to the dome in $F_s\mathrm{is}\frac{\overrightarrow{{\mathit{OF}}_s}}{r_2}$

). Is $\overrightarrow{r}\text{'}$

the direction of the refracted ray found, we search for μ such that ${\mathit{F}}_s^{\text{'}}=F_s+\mu \cdot \overrightarrow{r}\text{'}$

belongs to the inner surface of the dome (sphere of radius r ₁ ). It is a polynomial equation of degree 2, obviously analytical solution. We can then calculate the direction $\overrightarrow{i}$

of emerging ray in ${\mathit{F}}_s^{\text{'}}$

(the normal to the dome in ${\mathit{F}}_{\mathit{s}}^{\text{'}}\mathrm{being}\frac{\overrightarrow{{\mathit{OF}}_s^{\text{'}}}}{r_1}$

). We then calculate the intersection F of the line $\left({\mathit{F}}_s^{\text{'}},,\overrightarrow{i}\right)$

with the plane (inclined) of the transmitter.
F _s is selected when F belongs to the lower edge of the transmitter (1 ^st equation) and when (2 ^nd equation) | x - x _Fs | is:

• For the upper part of the lens: minimum
• For the lower part of the lens: maximum (which amounts to taking for F the lower corner of the transmitter, the opposite side laterally to M with respect to the plane $\left(O,,\overrightarrow{\mathrm{there}},,\overrightarrow{z}\right)$
  
  ).

), lorsque x est voisin de ou supérieur à la demi largeur de l'émetteur).In the case of the part of the lens at z > 0, F moves along the edge of the emitter to be rapidly constant (lower corner of the emitter, on the same side as M with respect to the plane $\left(O,,\overrightarrow{\mathrm{there}},,\overrightarrow{z}\right)$

), when x is close to or greater than the half width of the transmitter).

F _s belonging to a sphere centered given radius, determination returns to the search two unknowns, which is readily accomplished numerically from the analytical expression of the two conditions above.

It will be noted that in our new method, the determination of F is not coupled with that of M as was previously the case, which allows an improved stability of the calculations.

Figure 23a shows the isolux obtained with a diode and a lens thus constructed: the distribution of the beam is well centered and horizontal. This type of beam may advantageously complete a code-type beam.

The two modules according to FIG. 22b correspond to a variant of the modules according to FIG. 22a: each module uses a dome diode which is inclined at approximately 45 ° upwards with respect to the optical axis.

The method of construction of the lens is in principle identical to that described in the context of Figure 22a.

FIG. 23b shows the isolux curves obtained: it can be seen, in comparison with those of FIG. 23a, that the beam is much thinner, by less than 3%. The beam is intense (more than 40 lux at 25 meters), and it has a clear horizontal cut, above the horizontal below the glare threshold: this type of beam perfectly meets the requirements for a motorway-type beam regulatory.

II.d Construction method for variant IIβ

It should be noted that this method applies to all types of sources (with protective dome or emitter immersed in a protective material and known output face, including planar).

Let's choose an arbitrary point Fs on the surface of the source.

du rayon lumineux issu de f passant par Fs lorsqu'il sort de la source.Consider a point f located on the lower edge of the transmitter (supposedly rectangular, with long sides perpendicular to the direction vector of the optical axis y of the system). By the application of Descartes' laws of refraction, we easily calculate the direction ${\overrightarrow{v}}_o\left(f,,F_S\right)$

the light ray from f passing through Fs when it leaves the source.

soit nulle et sa composante suivant z positive, alors F est un foyer et $\left(F_S,{\overrightarrow{v}}_o\left(F,,F_S\right)\right)$

est un rayon limite. Dans le cas contraire, si Fc+ désigne le coin inférieur de l'émetteur de coordonnée la plus grande suivant x et si les composantes suivant x et z de ${\overrightarrow{v}}_o\left(F_{C+},,F_S\right)$

sont positives, Fc+ est un foyer et $\left(F_S,{\overrightarrow{v}}_o\left(F_{C+},,F_S\right)\right)$

est un rayon limite. Dans le cas contraire, si Fc- désigne le coin inférieur de l'émetteur de coordonnée la plus petite suivant x et si les composantes suivant x et z de ${\overrightarrow{v}}_o\left(F_{C-},,F_S\right)$

sont respectivement négative et positive, Fc- est un foyer et $\left(F_S,{\overrightarrow{v}}_o\left(F_{C-},,F_S\right)\right)$

est un rayon limite. Sinon, si la coordonnées de Fs suivant x est supérieure à celle du centre de l'émetteur, Fc- est un foyer et $\left(F_S,{\overrightarrow{v}}_o\left(F_{C-},,F_S\right)\right)$

est un rayon limite. Sinon, Fc+ est un foyer et $\left(F_S,{\overrightarrow{v}}_o(F_{C+},F_S\right)$

est un rayon limite.If there exists F such that the component along x (horizontal axis perpendicular to the optical axis) of ${\overrightarrow{v}}_o\left(F,,F_S\right)$

is zero and its component following positive z, then F is a focus and $\left(F_S,{\overrightarrow{v}}_o\left(F,,F_S\right)\right)$

is a limit radius. In the opposite case, if Fc + designates the lower corner of the next largest coordinate transmitter x and if the components along x and z of ${\overrightarrow{v}}_o\left(F_{\mathrm{VS}+},,F_S\right)$

are positive, Fc + is a home and $\left(F_S,{\overrightarrow{v}}_o\left(F_{\mathrm{VS}+},,F_S\right)\right)$

is a limit radius. In the opposite case, if Fc- denotes the lower corner of the smallest coordinate emitter following x and if the components along x and z of ${\overrightarrow{v}}_o\left(F_{\mathrm{VS}-},,F_S\right)$

are respectively negative and positive, Fc- is a focus and $\left(F_S,{\overrightarrow{v}}_o\left(F_{\mathrm{VS}-},,F_S\right)\right)$

is a limit radius. Otherwise, if the coordinate of Fs following x is greater than that of the center of the emitter, Fc- is a focus and $\left(F_S,{\overrightarrow{v}}_o\left(F_{\mathrm{VS}-},,F_S\right)\right)$

is a limit radius. Otherwise, Fc + is a home and $\left(F_S,{\overrightarrow{v}}_o(F_{\mathrm{VS}+},F_S\right)$

is a limit radius.

The rules set out in the previous paragraph fully describe the functions linking the focus and the limit radius corresponding to the point of emergence Fs of this ray out of the source.

et si on désigne par z₀ une cote (coordonnée suivant z) située $\frac{\delta }{\cos \begin{array}{}\end{array}i}\sin \left(\omega -i\right)$

au dessus de la cote du grand côté inférieur de l'émetteur, alors :

• si la coordonnée suivant z de Fs est supérieure à z₀,
  • o si la coordonnée x_FS suivant x de de Fs est comprise entre les coordonnées suivant x de Fc- et Fc+, alors F est le point du bord inférieur de l'émetteur de coordonnée X_F=X_FS.
  • o Si X_Fs est supérieur à la coordonnée suivant x de Fc+, le foyer est Fc+
  • o Si x_Fs est inférieur à la coordonnée suivant x de Fc-, le foyer est Fc-
• si la coordonnée suivant z de Fs est inférieure à z₀,
  • o si x_Fs est supérieur à la coordonnée suivant x du centre de l'émetteur, Fc- est le foyer
  • o si x_Fs est inférieur à la coordonnée suivant x du centre de l'émetteur, Fc+ est le foyer

In the case of a transmitter immersed in a material (plane exit surface source, inclined at an angle ω with respect to the vertical, with a transmitter parallel to the exit face, situated at a distance δ below that here, see fig. $i=\arcsin \left(\frac{\mathrm{sin\omega }}{{\mathrm{not}}_s}\right),$

and if we denote by z ₀ a dimension (coordinate z) located $\frac{\delta }{\cos \begin{array}{}\end{array}i}\sin \left(\omega -i\right)$

above the side of the lower side of the transmitter, then:

• if the following coordinate z of Fs is greater than z ₀ ,
  • o if the x _FS x coordinate of Fs lies between the x coordinates of Fc- and Fc +, then F is the point of the lower edge of the X coordinate emitter _F = X _FS .
  • o If X _Fs is greater than the following coordinate x of Fc +, the focus is Fc +
  • o If x _Fs is less than the following coordinate x of Fc-, the focus is Fc-
• if the following coordinate z of Fs is smaller than z ₀ ,
  • o if x _Fs is greater than the next coordinate x of the center of the transmitter, Fc- is the focus
  • o if x _Fs is less than the next coordinate x of the center of the transmitter, Fc + is the focus

In order to determine Ae6, we write the constancy of the optical path from the focus to the output wave surface along the boundary radii.

la normale à cette surface en P'. On détermine analytiquement l'intersection P de la surface de sortie torique As6 et de la droite $\left(\mathit{Pʹ},,\overrightarrow{n}\right),$

qui est le support d'un rayon limite (équation polynomiale de degré 4). On calcule ensuite la normale au tore en P et on en déduit, connaissant l'indice de réfraction de son matériau (n_l), la direction $\overrightarrow{r}$

du rayon réfracté à l'intérieur de la lentille (lois de Descartes). On cherche alors µ et Fs tels que P'P + n_lµ + MF_s + C_s = K (eqO) où $M=P+\mu \cdot \overrightarrow{r},$

où C_s est le chemin optique parcouru dans la source de Fs au foyer correspondant et où K est une constante qui détermine l'épaisseur de la lentille et tels que la droite (Fs, M) porte le rayon limite passant par Fs. Dans le cas le plus général, on obtient un système de trois équations (l'équation optique exprimée plus haut et l'appartenance de M à la droite portant le rayon limite en Fs) à trois inconnues (µ et deux paramètres pour Fs, qui est situé à la surface - connue- de la source).In practice, we proceed in the opposite direction to the propagation of light: let P be a point on the output wave surface and either $\overrightarrow{\mathrm{not}}$

the normal to this surface in P '. The intersection P of the toric exit surface As6 and the straight line is analytically determined $\left(\mathit{P\text{'}},,\overrightarrow{\mathrm{not}}\right),$

which is the support of a limit ray (polynomial equation of degree 4). We then calculate the normal torus in P and we deduce, knowing the index of refraction of its material (n _l ), the direction $\overrightarrow{r}$

of the refracted ray inside the lens (laws of Descartes). We then look for μ and Fs such that P'P + n _l μ + MF _s + C _s = K ( eqO ) where $M=P+\mu \cdot \overrightarrow{r},$

where C _s is the optical path traversed in the source of Fs at the corresponding focal point and where K is a constant which determines the thickness of the lens and such that the straight line (Fs, M) carries the limit radius passing through Fs. In the most general case, we obtain a system of three equations (the optical equation expressed above and the belonging of M to the line carrying the limit radius in Fs) to three unknowns (μ and two parameters for Fs, which is located on the surface - known- from the source).

In the case of a transmitter immersed in a material (plane exit surface source, with a rectangular emitter parallel to it), if z _M , coordinate of M along z, is greater than z ₀ , if x _M , coordinate of M following x lies between the coordinates on x of Fc- and Fc +, then x _F = x _Fs = x _M , otherwise F is located at the bottom corner of the transmitter on the same side as M (following x) relative to the center of the emitter, otherwise (z _M <Z ₀ ), F is located in the lower corner of the emitter on the opposite side to M (along x) from the center of the emitter.

(équation polynomiale de degré 2 liant les coordonnées de Fs à celles de F et de M et donc à µ), où $\overrightarrow{\mathit{v}}$

est la normale à la face de sortie de la diode. En outre, Fs appartient au plan de sortie de la diode, ce qui constitue une relation linéaire entre les coordonnées de Fs. Enfin $n_s^2\left(1-{\left(\overrightarrow{{\mathit{FF}}_s}\cdot \overrightarrow{v}\right)}^2\right)=(1-{\left(\overrightarrow{F_{s}M}\cdot \overrightarrow{v}\right)}^2)$

où $\Vert \overrightarrow{v}\Vert =1$

(conséquence de la seconde loi de Descartes de la réfraction), ce qui constitue, en y substituant l'expression d'une des coordonnées de Fs (par exemple suivant z) en fonction des autres (expression tirées des deux relations précédentes) une équation polynomiale de degré 4, de solution analytique, donnant z_Fs (dont on déduit les autres coordonnées) en fonction de µ. Dans le cas particulier considéré, C_S = n_s · FF_S et on peut donc exprimer l'équation optique eqO sous forme d'une équation à une seule inconnue : µ. Une telle équation se résout aisément numériquement à l'aide de plusieurs méthodes connues de l'homme de l'art. µ détermine M et en faisant varier P' on détermine l'intégralité de Ae6.In the particular case above, we have just established a law directly linking F to M (that is, to the unknown p). Due to the first law of Descartes (coplanarity of the rays and the normal to the diopter crossed), we know that $\left(\overrightarrow{F_{s}F}\wedge \overrightarrow{F_{s}M}\right)\cdot \overrightarrow{v}=0$

(polynomial equation of degree 2 linking the coordinates of Fs with those of F and M and thus with μ), where $\overrightarrow{\mathit{v}}$

is normal to the output face of the diode. In addition, Fs belongs to the output plane of the diode, which is a linear relationship between the coordinates of Fs. Finally ${\mathrm{not}}_s^2\left(1-{\left(\overrightarrow{{\mathit{FF}}_s}\cdot \overrightarrow{v}\right)}^2\right)=(1-{\left(\overrightarrow{F_{s}M}\cdot \overrightarrow{v}\right)}^2)$

or $\Vert \overrightarrow{v}\Vert =1$

(consequence of the second law of Descartes of the refraction), which constitutes, by substituting the expression of one of the coordinates of Fs (for example according to z) according to the others (expression drawn from the two previous relations) an equation polynomial of degree 4, of analytical solution, giving z _Fs (from which the other coordinates are deduced) as a function of μ. In the particular case considered, C _S = n _s · FF _S and we can therefore express the optical equation eqO in the form of an equation with a single unknown: μ. Such an equation is easily solved numerically using several methods known to those skilled in the art. μ determines M and by varying P 'the integrality of Ae6 is determined.

FIG. 24a shows a lens and its diode according to variant IIβ, in a configuration intended to produce a fog beam according to the representation of the isolux of FIG. 24b. FIG. 25a shows a lens and its diode according to variant IIβ, in a configuration intended to produce a motorway complement beam, as represented in the isolux of FIG. 25b. Figure 26 shows points and angles that have been used in the description of the construction method above, including zo and delta and omega angles.

In conclusion, the invention makes it possible to control the horizontal distribution of the light and to obtain a cut-off, possibly complex, with an exit surface for each module possibly allowing the assembly of several modules by creating a lens overall single smooth outer face.

It makes it possible to obtain optical modules, by different lens input face construction methods, different types of diodes, and different types of positioning of these diodes, to better adjust the parameters of the light beam, in particular its thickness. , the positioning of its break ...., the modules having a remarkable original style and a great compactness, especially in depth.

Claims (28)

A method of constructing a light source module providing a cut-off beam for a motor vehicle, comprising a lens and a light source disposed behind the lens from which it is separated by air, the light source being formed by minus one light-emitting diode, characterized in that the exit surface (As1-As5) of the lens (La-Ld) is selected so that it can be connected in a smooth and continuous manner with the exit surfaces of the lens. similar neighboring modules, and in that the entrance surface (Ae1-Ae5) of the lens is determined so as to obtain the breaking of the light beam without using an occulting cover. A method of constructing a light source module providing a cut-off beam for a motor vehicle, comprising a lens and a light source disposed behind the lens from which it is separated by air, the light source being formed by least one light emitting diode, characterized in that one chooses the exit surface (As1-As5) of the lens (La - Ld) and in that the inlet surface (Ae1-AE5) of the lens is determined relying on a horizontal generatrix, so as to obtain the cutoff of the light beam emitted by the module without using an occulting cover, and with a horizontal distribution of said light beam. Method according to one of the preceding claims, characterized in that the exit surface (As1-As5) of the lens is selected as substantially cylindrical or toroidal, the section of the exit surface of the lens in a vertical plane parallel to the optical axis being convex forward. Method according to one of the preceding claims, characterized in that the curvature (s) of the exit surface (As1-As5) of the lens is chosen to be substantially equal to the curvature (s) of the walls (W) which surround the module. Method according to one of the preceding claims for the construction of a module comprising an ellipsoidal reflector and a folder, characterized in that the exit surface (As1, As2) is chosen to be substantially that of a cylinder of revolution whose section by a vertical plane passing through the optical axis is a convex arc forward, and the Input surface (Ae1, Ae2) is constructed to be stigmatic between the second focus (Be) of the ellipsoidal reflector and the infinite. Method according to one of claims 1 to 4 for the construction of a diode module (Dc, Dd, De) in direct view of the lens, characterized in that the output surface (As3, As4, As5) is selected toric, vertical axis of revolution, and the input surface (Ae3, Ae4, Ae5) is constructed to create a horizontal cut. A light projector module providing a cut-off beam, for a motor vehicle, comprising a lens and a light source arranged behind the lens from which it is separated by air, the light source comprising at least one light-emitting diode, characterized in that that the exit surface (As1-As5) of the lens is fully convex forward and is such that it can be connected in a smooth, continuous surface with the lens exit surfaces of similar neighboring modules, and the surface input (Ae1-Ae5) of the lens is defined so that the module gives a light beam cut without intervention of an occulting cache, including vertical. A light projector module providing a cut-off beam, for a motor vehicle, comprising a lens and a light source arranged behind the lens from which it is separated by air, the light source comprising at least one light-emitting diode, characterized in that that the exit surface (As1-As5) of the lens is entirely convex towards the front, and the entrance surface (Ae1-Ae5) of the lens is defined by relying on a horizontal generatrix, so that that the module gives a light beam cut without intervention of an occulting cover, in particular vertical, and with a horizontal distribution. Module according to one of Claims 7 or 8, characterized in that the entrance surface (Ae6) of the lens is calculated in such a way that a family of light rays, called limit radii, originating from the transmitter of the light source, emerge from the lens so that they are all normal, at the points where they meet, at a given surface called output wave surface. Module according to the preceding claim, characterized in that the exit wave surface is cylindrical, vertical generators and section any right. Module according to claim 7 or 8, characterized in that the light source (De) comprises a light-emitting diode in direct view of the lens. Module according to the preceding claim, characterized in that said diode is disposed in an oblique plane with respect to the optical axis of said module. Module according to one of the preceding claims, characterized in that the light source (De) comprises a light-emitting diode having a transparent protective dome (21) located above the emitter (22). Module according to the preceding claim 9 or 10, characterized in that the diode is sufficiently inclined so that the angle under which is seen the emitter of the diode from a majority of points of the lens is smaller than it would be with a lens disposed in a plane perpendicular to the optical axis of the module. Module according to one of the preceding claims 9 to 11, characterized in that the diode is sufficiently inclined so that the radius which is more inclined with respect to the axis of the emitter of the diode reaching the lens is smaller than the limit angle of the distribution of the light beam emitted by the diode. Module according to one of the preceding claims 9 to 12, characterized in that the diode is inclined with respect to the optical axis of the module from +/- 35 ° to +/- 55 °, in particular from +/- 40 ° to +/- 50 °. Module according to one of the preceding claims 9 to 13, characterized in that it is capable of emitting a beam or a portion of a motorway-type beam, in particular having a beam thickness of less than 5%, in particular less than 3% , a high intensity, especially at least 40 lux at 25 meters, and a cut above the horizontal. Module according to one of the preceding claims 7 or 8, characterized in that the light source (De) comprises a light-emitting diode in direct view of the lens, and that , in the mounting position, the transmitter of the diode and the lens are inclined laterally in a vertical plane, in particular in order to obtain a beam or a portion of light beam obliquely cut. Light projector module according to one of the preceding claims, characterized in that the exit surface (As1-As5) of the lens is cylindrical or toric, the section of the exit surface of the lens by a vertical plane parallel to the optical axis being convex forward. Light projector module according to one of claims 7 or 8, comprising an ellipsoidal reflector and a folder, characterized in that the exit surface (As1, As2) is chosen to be that of a cylinder of revolution whose section by a vertical plane passing through the optical axis is a convex arc forward, and the entrance surface (Ae1, Ae2) is constructed to be stigmatic between the second focus (Be) of the ellipsoidal reflector and the infinite . Module according to the preceding claim, characterized in that the shape of the edge (10) of the folder is provided so that the light beam has a V cut. Module according to claim 17 or 18, characterized in that the edge of the folder has a bump deformation (11) to compensate, in part, the aberrations of the lens. Module according to claim 20 or 21, characterized in that the edge (10a) of the folder has on both sides of the vertical plane passing through the optical axis two bumps (13, 14) connected by a bowl portion ( 15) to form an additional module for a highway code, reinforcing the light in the axis below the horizontal. Module according to Claim 20, characterized in that the input surface (Ae1) is such that the optical path is constant from the external focus (Be) of the reflector to a plane (Π1) tangential to the exit face ( As1) at its point of intersection (h1) with the optical axis of the module. Module according to claim 20, characterized in that the focus of the lens (Lb) is offset transversely with respect to the optical axis and the module illuminates in a lateral direction relative to the optical axis, the entrance surface (Ae2) of the lens (Lb) being such that the optical path is constant between the focus (18) of the lens and a vertical plane whose trace (19) on the horizontal plane of the optical axis is inclined relative to this axis. Module according to one of claims 7 to 19, characterized in that the light source (Dc, Dd, De) is in direct view of the lens, the exit surface (As3, As4, As5) of the lens is toric. vertical axis of revolution, and the input surface (Ae3, Ae4, Ae5) is defined to give a beam with horizontal cutoff. Module according to one of the preceding claims 7 to 26, characterized in that the light source (Dc, Dd) consists of a rectangular lambertian emitter placed in a vertical plane, orthogonal to the optical axis. Module according to one of claims 7 to 26, characterized in that the light source (De) is constituted by a light-emitting diode having a transparent protective dome (21) situated above the emitter (22), itself placed in the air.

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