FR3019263A1 - OPTICAL GUIDE WITH PRISMATIC PATTERNS FORMING GALBAN DIOPTRES - Google Patents

Abstract

The invention relates to an optical guide (204), in particular for a lighting or signaling device (202) for a motor vehicle, made of transparent material and in the general shape of a plate, with an entry face (206) of light emitted by one or more light sources; two opposite guide faces corresponding to the two main faces of the plate, able to guide the light by total reflection; patterns (214), generally in the form of a prism, on one of the two guide faces, forming diopters (216 ', 216 ") adapted to reflect towards the opposite guide face the incident rays from the light source or sources. The diopters (216 ', 216 ") of the patterns (214) are generally curved towards the incident rays.

Description

The invention relates to the field of lighting and more particularly to the field of indoor and / or outdoor lighting and light signaling for a motor vehicle. The invention relates to the field of lighting and / or light signaling by means of optical guide. In the field of lighting and signaling of motor vehicles, it is more and more frequent to use optical guides. Indeed, they have the advantage of being able to take very varied geometric shapes and to bring an illuminating surface even in inaccessible areas of a lighting and / or signaling device. This is particularly interesting in the current context where car manufacturers seek to give their vehicles a signature of their own, including offering complex shapes to lighting and / or signaling devices.

By optical guide, it is intended in the present application a transparent or translucent piece within which light rays propagate in a controlled manner from one end of the guide, called the input face, to at least one face of exit. The propagation of light in a controlled manner is generally effected by successive total reflections on various reflection faces internal to the optical guide. The optical guides may have a plate shape, flat or not, with two opposite guide faces corresponding to the two main faces of the plate, able to guide the light by total reflection. Published patent document US 2010/0124076 A1 discloses an optical guide for providing backlighting of a liquid crystal type plane display screen. It has a general flat plate shape, with two opposite guide faces corresponding to the two main faces of the plate and with a light entry face. One of the two guide faces comprises a series of cavities of prismatic shape and forming dioptres with the air inside these cavities. These diopters reflect light from a light source disposed at an edge of the plate forming an entrance face, these rays then being reflected towards the opposite guide face thus also forming an exit face. This teaching has the particularity that the faces of the prisms forming the diopters are oriented so as to make an angle of 45 ° with the light rays extending from the light source to the dioptres in question. This measurement makes it possible to ensure a substantially constant light intensity over the entire surface of the plane optical guide and a direction of uniform ray output. This optical guide attempts to produce a generally uniform backlight with a limited number of light sources, in this case one or two light sources. The degree of uniformity, although sufficient for a telephone or laptop screen backlight function, is, however, insufficient for applications outside the field of flat-screen back-lighting, such as for applications in particular. signaling light for a motor vehicle, in which the optical guides are often curved. The invention aims to provide an optical guide overcomes at least one of the disadvantages of the state of the art mentioned above. More particularly, the invention aims to provide an optical guide capable of generating uniform illumination over a certain extent of the guide, whether said guide is flat or curved. The subject of the invention is an optical guide, in particular for a motor vehicle lighting or signaling device, made of a transparent material and in the general shape of a plate, with: a light entry face emitted by one or more sources of light; two opposite guide faces corresponding to the two main faces of the plate, able to guide the light by total reflection; patterns, in the general shape of a prism, on one of the two guide faces, forming diopters able to reflect towards the opposite guide face the incident rays from the light source or sources; remarkable in that the diopters of the patterns are generally curved towards the incident rays. According to the invention, the curved nature of the diopters results in a concavity and / or a convexity. According to a first variant embodiment, the prismatic patterns are cavities. According to a second variant, these patterns are protuberances.

According to an advantageous embodiment of the invention, the section of the patterns along a longitudinal plane oriented essentially along the incident rays has a profile comprising, successively, a first portion corresponding to the reflecting curved diopters, and a second generally upright portion. Advantageously, the section of the patterns comprises a third intermediate portion, interposed between the first and the second portion, which is generally parallel to the guide face on which the patterns are formed. According to an advantageous embodiment of the invention, the second portion of the pattern profile forms an angle with the guiding surface on which the patterns are formed, between 60 ° and 90 °, preferably between 65 ° and 75 °. According to an advantageous embodiment of the invention, the first portion of the pattern profile forms an angle 13 with the guiding surface on which the patterns are formed, between 20 ° and 50 °, preferably between 25 ° and 45 °, more preferably between 30 ° and 40 °. According to an advantageous embodiment of the invention, each of the patterns comprises two lateral faces with respect to the main direction of the incident rays, preferably said two faces being inclined so as to approach the guiding face on which said patterns are formed. According to an advantageous embodiment of the invention, each of the two lateral faces of the patterns is generally convex or concave towards the outside. According to an advantageous embodiment of the invention, the width of the reflective diopters of the patterns decreases from the guiding surface on which said patterns are formed to at least 50%, preferably 70% of the height of said diopters. Advantageously, the decrease in the width between the base and its top is of the order of 10%. According to an advantageous embodiment of the invention, the intersection of the reflective diopters with one of the two lateral faces of the patterns forms a profile curved towards the intersection of said diopters with the other of said lateral faces. According to an advantageous embodiment of the invention, each of the patterns comprises a bottom formed by a generally rectangular surface elongate in a direction transverse to a longitudinal direction oriented substantially along the incident rays, said surface preferably being curved towards the opposite guiding face to that on which the patterns are formed, in a longitudinal plane and / or in a transverse plane. According to an advantageous embodiment of the invention, the input face comprises collimator means suitable for the rays propagating along the guide in a main direction, said means preferably comprising Fresnel surfaces. According to an advantageous embodiment of the invention, the patterns are distributed in staggered rows, preferably in a repetitive, line-by-line arrangement, where one line out of two is offset with respect to the line that precedes or follows it, said corresponding offset preferentially at half the distance between two adjacent patterns of a line. According to an advantageous embodiment of the invention, the average size of the patterns is less than 1 mm and / or greater than 0.1 mm. According to an advantageous embodiment of the invention, the patterns are distributed in a repetitive arrangement, the size of the patterns, preferably the width and the height of the reflective diopters, gradually increasing as one moves away from the face input, so as to compensate for the progressive decrease in light power propagating along the guide. According to an advantageous embodiment of the invention, the size of the patterns, preferably the width and the height of the reflective diopters of said patterns, increases by more than 10%, preferably by more than 30%, more preferably by more than 50%, along of the guide. According to an advantageous embodiment of the invention, the patterns are distributed in a repetitive arrangement, the density of the patterns gradually increasing as one moves away from the input face, so as to compensate for the progressive decrease. light power propagating along the guide. According to an advantageous embodiment of the invention, each of the patterns comprises two diopters able to reflect towards the opposite guide face the incident rays coming from the light sources in two different directions, said diopters being generally curved toward the incident rays.

The subject of the invention is also a lighting and / or light-signaling module, in particular for a motor vehicle, comprising an optical guide and at least one, preferably several light sources, remarkable in that the optical guide is in accordance with the invention .

The invention also relates to a light signaling device for a motor vehicle, comprising a direction indicator module, a rear lantern module or front and / or a stop lamp module, remarkable in that said module or at least one of said modules is in accordance with the invention. Other features and advantages of the present invention will be better understood from the description and drawings in which: FIG. 1 is a perspective view of a lighting and / or signaling module according to a first embodiment of the invention; FIG. 2 is a diagrammatic cross-sectional illustration of the optical waveguide of FIG. 1; FIG. 3 is a perspective representation of one of the cavities of the optical waveguide of FIGS. 1 and 2; FIG. 4 is an illustration of the profile of the cavity of FIG. 3; FIG. 5 is a perspective representation of a cavity of an optical guide according to a second preferred embodiment of the invention; FIG. 6 is an illustration of the distribution of cavities on an optical guide according to the first or the second embodiment; FIG. 7 is a perspective representation of an optical guide according to a third embodiment; FIG. 8 is a perspective representation of an optical guide according to a fourth embodiment; FIG. 9 is a perspective representation of an alternative cavity to the cavities of FIGS. 3 and 5, corresponding to a fifth embodiment of the invention. Figure 1 illustrates in perspective a lighting module and / or signaling 2 according to a first embodiment of the invention. The module 2 comprises an optical guide 4 and light sources 8 arranged, in this case, on a plate 9. The light sources 8 are preferably of the electroluminescence diode type. The optical guide 4 is made of a transparent or translucent material in the form of a curved plate extending in a main direction. It comprises two main faces 10 and 12 forming guide faces of the guide. It also comprises laterally an input face 6, which may include so-called Fresnel surfaces acting as a collimator of the light emitted by the light sources 8 arranged in front of these surfaces. The rays emitted by these light sources 8 and entering the optical guide 4 via this input face 6 then propagate substantially in the main direction of the guide, by successive reflections on the guide faces 10 and 12. The angle of the incidence of most of these rays with these faces is greater than the limit angle of refraction defined by the Snell-Descartes law (t9 = n, where n1 is the index of nl refraction of the material of the guide and n2 is the refractive index of ambient air). These rays are therefore reflected by the principle of total reflection. The guiding rear face 10 has the particularity of having prismatic shape patterns (visible in FIG. 1), each of these patterns forming a diopter with the ambient air, able to reflect the light rays essentially towards the guiding face 12 opposite. Figure 2 is a schematic sectional view of the guide of Figure 1, the section being in a longitudinal plane (in this case a generally vertical plane given the orientation of Figure 1). The guide is represented as being plane whereas in reality it can have a curve as can be seen in FIG. 1. It can be seen in FIG. 2 the patterns which are here cavities 14 of prismatic shape formed on one of the faces. 10 and 12, in this case on the rear face 10. The cavities 14 form with the ambient air which fills them dioptres able to reflect the rays coming from the light sources 8 and propagating along the optical guide 4. On the occasion of these reflections, these rays are directed towards the guide face 12 opposite to that comprising the cavities 14, which also serves as an exit face. Figure 3 illustrates one of the cavities 14 in perspective. The volume delimited by the prismatic surface shown in FIG. 2 corresponds to the cavity filled with ambient air. The base of the prism represents the opening of the cavity in the extent of the rear guide face 10 (FIGS. 1 and 2). The material in contact with the other faces, in this case the faces 16, 18, 20, 22 and 24 is the transparent or translucent material of the guide. The front or reflection face 16 forms the diopter which is able to reflect the rays propagating in the guide to this face in question. The rear face 18, essentially opposite to the front face 16 is configured to allow the refraction of rays propagating in the guide to this face in question. These rays are then refracted a first time at the passage of this diopter, they then pass through the air volume of the cavity and are then refracted a second time to the passage of the diopter of the front face 16. The side faces 22 and 24 n ' have no major optical role. They form in fact the connection between the front 16 and rear 18, so as to define the cavity. The upper face 20 also forms a connecting face between the upper edges of the front faces 16 and rear 18. Figure 3 illustrates the profile of the cavity 14 of Figures 1 to 3. It can be seen the faces 16, 18 and 20. More specifically, the front or reflection face 16, forming the reflection diopter of the rays towards an exit face, is generally curved so as to form a concave or convex profile seen from the cavity 14. This face may have a radius of curvature average less than or equal to 3 times the depth of the cavity. This face forms an angle 13 with the guiding surface 10 on which the cavity 14 is formed. This angle can be between 20 ° and 50 °, preferably between 25 ° and 45 °, more preferably between 30 ° and 40 °. The angle 13 and the profile of the face 16 are configured to allow the rays propagating in the guide towards said face to undergo reflections according to the principle of total reflection. In other words, these rays must meet the face 16 with an angle of incidence greater than the refraction limit angle mentioned above. For a material such as polycarbonate with a refractive index of 1.59, the refractive limit angle is of the order of 39 °. This means that the rays incident on the face 16 at an angle greater than 39 ° will be reflected towards the exit face, corresponding to the opposite guiding face to that having the cavities. The ray 26 shown in solid lines in Figure 4 and meeting the face 16 at a point A forms with said face an angle of incidence (measured with respect to the normal to said face) of the order of 45 ° -50 ° , that is, an angle greater than 39 °. This ray is then reflected towards the exit face. The ray 28 shown in broken lines and meeting the face 16 at the point A has a lower angle of incidence, in this case less than the limit angle of refraction. It is then refracted a first time to the passage of the diopter of the front face 16 and a second time to the passage of the diopter of the rear face 18. The rounded or curved profile of the front face 16 can change the inclination along of said profile. More specifically, the inclination of the face 16 relative to the normal to the guide face 10 increases as one goes through the profile of the face 16 from the face 10 to the face 20. This means that a radius such as the radius 30 shown alternately dotted and meeting the face 16 at a "high" point B (relative to the orientation of Figure 4), that is to say at a point close to the face 20, may be reflected while having a lower inclination than a ray meeting the face 16 at a point "lower" or closer to the face 10, such as the radius 26. The spokes having undergone reflection on the face 10, further upstream of the diopter 16 has indeed a more "flat" orientation, that is to say, closer to the longitudinal direction of the guide and will be likely to meet a "high" portion of said dioptre.

The rear face 18 is preferably of generally rectilinear profile. It forms an angle α with the face 10, which can be between 60 ° and 90 °, preferably between 65 ° and 85 °, more preferably between 70 ° and 85 °. The fact of having an angle less than 90 ° has the advantage of promoting demolding during the production of the guide with its cavities by molding. The angle a is preferably greater than the angle R. The rays incident on the rear face 18 can pass through the cavity without undergoing reflection. Indeed, the rays propagating in the guide towards the rear face 18 (that is to say from the left in FIG. 4) meet the rear face 18 with a reduced angle of incidence, less than the limit angel. of refraction. Indeed, the majority of rays propagating in the guide have a limited inclination relative to the mean plane of the guide, in this case this inclination is less than 30 °. Given the high value of the angle α, the rays propagating in the guide following a rising inclination, that is to say the rays that move away from the rear guide face as and when they approach the face 18, like the radius 32 shown in dotted lines in FIG. 4. The angle of incidence of this radius 32 with the face 18 is the sum of its inclination and the inclination of the face 18. If we consider a maximum inclination of 30 ° of these radii and a slope of the face 18 of the order of 8 ° (corresponding to an angle α of 82 °) with respect to the perpendicular to the guide face 10 , the maximum angle of incidence of such rays will be 38 °, that is to say less than the limit angle of refraction (which is 39 °) for a diopter polycarbonate / air. It can be seen in Figure 4 that the ray 32 is refracted twice, allowing it to continue to propagate in the guide.

The upper face 20 connecting the faces 16 and 18 is generally parallel to the lower guide face 10. It may have a rounded connection with the face 16, such as for example a radius of curvature greater than or equal to 5%, preferably 10% , the depth of the cavity (or respectively the height of the protuberance, when the pattern is made in the latter form).

The upper face 20 may be generally flat or may be curved towards the exit face, that is to say upwards in the configuration of FIG. 3. It will be noted that this upper face 20 is optically optional . However, it will be advantageously provided because it facilitates the manufacturing process of the guide according to the invention by injection molding plastic material, by promoting the release of the workpiece and ensuring greater robustness and reproducibility of the prismatic pattern. FIG. 5 illustrates an alternative and optimized form of the cavity of FIG. 3, corresponding to a second preferred embodiment of the invention. The reference numbers of the first mode illustrated in FIGS. 1 to 4 are used for identical or corresponding elements, these numbers however being increased by 100. Specific numbers between 100 and 200 are used for the specific elements. The cavity 114 is similar to the cavity 14 of FIG. 3, in particular in that it is prismatic and comprises a front reflection face 116, a transmission rear face 118, an upper face 120 connecting the upper edges of the front faces 116. and rear 118 and side faces 122 and 124. However, the cavity 114 differs from that of Figure 3 in that the front face of reflection 116 has a variable width along its height. Also, the lateral faces 122 and 124 are no longer flat but curved outwards. The intersections 115 and 117 between these lateral faces 122, 124 and the front face 116 have, each and preferably symmetrically, a profile curved towards the other intersection. This configuration causes the lower portion of the front face 116 to reflect more rays than the upper portion. This effect is particularly interesting for optical guides of a certain length, insofar as it is mainly the rays meeting the reflection faces in the lower zone that are reflected. The resulting light image can then be more homogeneous. Indeed, the "light sources" that constitute the reflection faces 116 may be wider and therefore less distant from each other, and the rays may however propagate along the guide being gradually reflected towards the exit face. In addition, the curved shape of the lateral faces makes it possible to deflect by total reflection a portion of the rays propagating between the cavities, these deviations permitting lateral diffusion of the rays, which also has the effect of increasing the homogeneity of the image produced light. The average radius of curvature of the lateral faces 122 and 124 at the base of the cavity may be between 50% and 150% of the maximum width of the cavity. This radius of curvature gradually decreases as one moves towards the top, in this case towards the upper face 120. The width of the reflection face 116 at the base of the cavity may be greater at 150% of the width at the top of the cavity. The rear face 118 may have a substantially constant width, preferably substantially equal to that of the upper face 120 and the width of the reflection face 116 at the height of the upper face 120. The upper face 120 may have a slightly curved profile in longitudinal planes, that is to say, planes directed along the main direction of the incident rays, and / or in transverse planes, that is to say, planes perpendicular to the longitudinal planes.

The reflection face 116 and / or the rear face 118 may also have a slightly curved profile in transverse planes, this or these profiles being curved outwards. This improves the transverse homogeneity of the light beam. The curved shapes mentioned above promote the demolding of the mold element or elements forming the cavities. They thus make it possible to obtain less wear of the mold and, consequently, greater precision. FIG. 6 schematically illustrates the distribution of the cavities over the extent of an optical waveguide, this distribution being applicable in particular to the cavities of FIG. 3 and FIG. 5. The module 2/102 shown schematically in FIG. thus to the first and second embodiments. The cavities 14/114 are distributed in staggered rows along the length of the guide 4/104, in a repetitive, line-by-line arrangement, where every other line is offset relative to the line that precedes or follows it. The offset may be half the distance between two cavities adjacent to a line. The guide may include on the input side of the light rays collimator means adapted so that the rays propagate along the guide in a main direction. In this case, the lines of the staggered arrangement are perpendicular to that direction. The staggered arrangement is interesting in that it also helps to promote the homogeneity of the light image produced. FIG. 7 illustrates a light signaling module according to a third embodiment of the invention. The reference numbers of the first mode illustrated in FIGS. 1 to 4 are used for the identical or corresponding elements, these numbers however being increased by 200. Specific numbers between 200 and 300 are used for the specific elements. The module 202 comprises an optical guide 204 in the form of an L-shaped and curved plate. The guide comprises an inlet face 206 provided with Fresnel surfaces 234 serving as a light collimator. Light sources (not shown), in particular of the electroluminescence diode type, are intended to be arranged along the input face. It is in this case a signaling module of the rear lantern type of motor vehicle. It could also be a direction indicator (flashing) and / or a stop light.

Cavities 214 of the type described in connection with FIG. 5 are distributed over one of the guide faces of the guide, in this case on the rear face, only the front guide face being visible in FIG. 7. The cavities are distributed in an L-shaped extent as well, covering a major part of the extent of the guide. It is interesting to observe in Figure 7 that the density of the cavities increases as one moves away from the entrance face. This is due to the fact that the size of the cavities increases as one moves away from the entry face 206. FIG. 7 illustrates an enlargement of a first zone near the face of entry, showing cavities 214 'of reduced size, and a second zone near the opposite end, showing cavities 214' of substantially greater size, in this case, it is the width and the height of the diopters of reflection 216 'and 216 "which vary as one moves away from the input face 206. This measure compensates for the progressive loss of light power propagating in the guide, so as to ensure homogeneity of the luminous image produced. The variation in width depends in particular on the length of the guide. The size of the cavities, preferentially the width of the reflective dioptres of said cavities, increases by more than 10%, preferably by more than 30%, more preferably by more than 50%, along the guide. FIG. 8 illustrates a light signaling module according to a fourth embodiment of the invention. The reference numbers of the first mode illustrated in FIGS. 1 to 4 are used for identical or corresponding elements, these numbers however being increased by 300. Specific numbers between 300 and 400 are used for the specific elements. The module 302 comprises an optical guide 304 in the form of a flat plate. The guide comprises an inlet face 306 provided with Fresnel surfaces 334 serving as a light collimator. Light sources (not shown), in particular of the electroluminescence diode type, are intended to be arranged along the input face. This is a light signaling module of the type rear brake light of a motor vehicle. It could also be a direction indicator (flashing) and / or a lantern. Similarly to the module of FIG. 7, cavities 314 of the type of those described in relation to FIG. 5 are distributed on one of the guide faces of the guide, in this case on the rear face, only the front guide face being visible. Figure 8. The cavities are distributed in a rectangle-like extent, covering a major part of the guide's extent. Similarly to the module of Figure 7, the density of the cavities increases as one moves away from the entrance face. This is due to the fact that the size of the cavities increases as one moves away from the entrance face 306. Always similar to FIG. 7, FIG. 8 illustrates an enlargement of a first zone to proximity of the entrance face, showing cavities 314 'of reduced size, and a second zone near the opposite end, showing cavities 314' of substantially larger size, in this case it is the width and the height of reflective diopters 316 'and 316 "which vary as one moves away from the input face 306. This compensates for the progressive loss of light power propagating in the guide, so to ensure a homogeneity of the produced luminous image. The variation in width depends in particular on the length of the guide. The size of the cavities, preferentially the width of the reflective diopters of said cavities, varies less than in the module of FIG. 7 because of its more limited extent.

It should be noted that in the modules of FIGS. 7 and 8, the cavities may be different from that of FIG. 5. They may indeed be in particular of the type of FIG. 3, the size of the reflecting faces being modulated similarly to those of the cavities 214, 214 ', 214 ", 314, 314' and 314" visible in FIGS. 7 and 8. In general, that is to say for all the embodiments, the average size of the cavities is preferentially between 0.1 mm and 1 mm, more preferably between 0.3 mm and 0.6 mm. The distance between the cavities is preferably between 0.2 mm and 5 mm. The density of the cavities, that is to say the area covered by the cavities per unit area of the guide, may be between 10% and 80%. These measurements also make it possible to ensure good homogeneity of the light image produced by the optical guide. FIG. 9 illustrates an alternative configuration of the prismatic patterns of the preceding embodiments, this configuration corresponding to a fifth embodiment. The reference numbers of the first mode illustrated in FIGS. 1 to 4 are used for the identical or corresponding elements, these numbers however being increased by 400. Specific numbers between 400 and 500 are used for the specific elements. The signaling and / or lighting module illustrated in a summary manner in FIG. 9 comprises an optical guide 404 of which one of the cavities 414 is illustrated. It has the particularity of presenting several reflection faces, in this case two adjacent faces 4161, 4162 forming reflecting diopters in accordance with the reflection face 16 of the cavity 14 of FIG. 3. The longitudinal profile (as illustrated in Figure 4) can be generally curved. The same can be said for the transverse profile, as can be seen at the base of the prism in FIG. 9. The upper face 420 is of reduced size considering the inclination of the two faces 4161, 4162. It is referred to to the detailed description of the cavity of Figures 3 and 4 with respect to the geometry of the reflection faces, each of these faces may be in accordance with the face 16 of the cavity 14 of these figures.

The cavity 414 may advantageously be used in an optical guide configuration comprising two input faces capable of supplying light each of one of the two reflection faces of the cavities. It should be noted that the prismatic cavity of FIG. 9 could have two opposite faces of reflection, the lateral faces being able to be essentially flat 10 as in FIG. 3 or else curved as in FIG. 5. In general, the prismatic cavities can be performed during the molding of the optical guide, the geometry described above being favorable to demolding operations. In addition, the description which has just been made with reference to patterns made in the form of cavities applies to patterns of identical geometry made in the form of protuberances, without departing from the scope of the present invention. Still generally, the optical guides described above and in accordance with the invention may be used in particular in projectors, interior lighting devices and light-signaling devices of motor vehicles.

Claims (18)

REVENDICATIONS1. Optical guide (4; 104; 204; 304; 404), in particular for a lighting or signaling device for a motor vehicle, made of a transparent material and in the general shape of a plate, with: an input face (6; 206, 306, 406) of light emitted by one or more light sources; - two opposite guide faces (10, 12) corresponding to the two main faces of the plate, able to guide the light by total reflection; - patterns (14; 114; 214; 314; 414), generally prism-shaped, on one of the two guide faces forming diopters (16; 116; 216; 316; 4161; 4162) adapted to reflect towards the opposing guide face the incident rays from the light source or sources; characterized in that the diopters (16; 116; 216; 316; 4161; 4162) of the patterns (14; 114; 214; 314; 414) are generally curved towards the incident rays. 2. Optical guide (4; 104; 204; 304) according to claim 1, characterized in that the section of the patterns (14; 114; 214; 314) along a longitudinal plane oriented essentially along the incident rays has a profile comprising , successively, a first portion (16; 116; 216; 316) corresponding to the reflecting curved diopters and a second portion (18; 118) generally straight. 3. optical guide (4; 104; 204; 304) according to claim 2, characterized in that the second portion (18; 118) of the pattern profile forms an angle with the guide face on which the patterns are formed, between 60 ° and 90 °, preferably between 65 ° and 75 °. 4. optical guide (4; 104; 204; 304) according to one of claims 2 and 3, characterized in that the first portion (16; 116; 216; 316) of the pattern profile forms an angle 13 with the face on which the patterns are formed, between 20 ° and 50 °, preferably between 25 ° and 45 °, more preferably between 30 ° and 40 °. 5. optical guide (4; 104; 204; 304) according to one of claims 2 to 4, characterized in that each of the patterns (14; 114; 214; 314) comprises two lateral faces (22, 24; 124) relative to the main direction of the incident rays, preferably said two faces being inclined so as to approach one another from the guiding face on which said patterns are formed. 6. optical guide (104; 204; 304) according to claim 5, characterized in that each of the two lateral faces (122, 124) of the patterns (114; 214) is generally convex or concave outwards. 7. optical guide (104; 204; 304) according to one of claims 5 and 6, characterized in that the width of the reflective diopters (116; 216; 316) patterns (114; 214; 314) decreases from the face on which said patterns are formed up to at least 50%, preferably 70% of the height of said diopters. 8. optical guide (104; 204; 304) according to one of claims 5 to 7, characterized in that the intersection (115, 117) of the reflective dioptres (116; 216; 316) with one of the two lateral faces of patterns (114; 214; 314) form a curved profile toward the intersection of said diopters with the other of said side faces. 9. optical guide (4; 104; 204; 304) according to one of claims 1 to 8, characterized in that each of the patterns (14; 114; 214; 314) comprises a bottom (120) formed by a surface generally rectangular elongated in a direction transverse to a longitudinal direction oriented substantially along the incident rays, said surface being preferably curved toward the opposite guiding face to which the patterns are formed, in a longitudinal plane and / or in a transverse plane. 10. optical guide (4; 104; 204; 304; 404) according to one of claims 1 to 9, characterized in that the input face (206; 306) comprises collimator means (234; 334) adapted to the rays propagate along the guide along a main direction, said means preferably including Fresnel surfaces. 11. optical guide (4; 104; 204; 304; 404) according to one of claims 1 to 10, characterized in that the patterns (14; 114; 214; 314; 414) are distributed in a staggered arrangement, preferably in a repetitive arrangement, line to line, where every other line is offset from the line that precedes or follows it, said offset corresponding preferably to half the distance between two adjacent patterns of a line. 12. optical guide (4; 104; 204; 304; 404) according to one of claims 1 to 11, characterized in that the average size of the patterns (14; 114; 214; 314; 414) is less than 1 mm. and / or greater than 0.1 mm. 13. optical guide (4; 104; 204; 304; 404) according to one of claims 1 to 12, characterized in that the patterns (14; 114; 214; 314; 414) are distributed in a repetitive arrangement; size of the patterns, preferably the width and height of the reflective diopters (16; 116; 216; 316; 4161; 4162), progressively increasing as one moves away from the entrance face so as to to compensate for the gradual decrease in light power propagating along the guide. 14. optical guide (4; 104; 204; 304; 404) according to claim 13, characterized in that the size of the patterns (14; 114; 214; 314; 414), preferably the width and height of the reflective dioptres of said reasons, increases by more than 10%, preferably by more than 30%, more preferably by more than 50%, along the guide. 15. optical guide (4; 104; 204; 304; 404) according to one of claims 1 to 14, characterized in that the patterns (14; 114; 214; 314; 414) are distributed in a repetitive arrangement, the density patterns gradually increasing as one moves away from the entrance face, so as to compensate for the progressive decrease in light power propagating along the guide. 16. optical guide (404) according to one of claims 1 to 15, characterized in that each of the units (414) comprises two dioptres (4161, 4162) adapted to reflect towards the opposite guide face the incident rays from the sources luminous in two different directions, said dioptres being generally curved towards the incident rays. 17. Lighting and / or light-signaling module (2; 102; 202; 302; 402) in particular for a motor vehicle, comprising an optical guide and at least one, preferably several light sources, characterized in that the optical guide ( 4; 104; 204; 304; 404) according to one of claims 1 to 16. 18. A light signaling device for a motor vehicle, comprising a direction indicator module, a rear lantern or front module and / or a stop lamp module, characterized in that said module or at least one of said modules (2; 102; 202; 302; 402) is in accordance with claim 17.