Luminous module for vehicle lighting device with deviating light guide

Abstract

A vehicle luminous module intended to generate a light beam along an optical axis includes primary light guides each including an entrance dioptric interface and an exit, and a light source arranged facing an entrance dioptric interface. A projecting assembly includes a focal region and an exit member, the projecting assembly being arranged so that the light rays passing through said focal region and reaching the exit member are imaged in a projection field downstream of said projecting assembly. The exits of the guides are arranged level with the focal region. The luminous module includes at least one secondary light guide distinct from the primary light guides, and arranged so as to deviate light rays generated by the light source so that they do not reach the exit member, and/or so as to spread said light rays in said projection field.

Claims

1. A vehicle luminous module intended to generate a light beam along an optical axis, and comprising: primary light guides each comprising an entrance dioptric interface and an exit; a light source arranged facing a respective entrance dioptric interface of at least one primary light guide; a projecting assembly comprising a focal region and an exit member, said projecting assembly being arranged so that light rays passing through said focal region and reaching the exit member are imaged in a projection field downstream of said projecting assembly, wherein exits of the primary light guides are arranged level with the focal regions; and one or more secondary light guides placed in a same horizontal row as the primary light guides, and arranged so as to deviate stray light rays from the exit member, deviate said stray light rays to spread in said projection field, or both deviate said stray light rays from the exit member and deviate said stray light rays to spread in said projection field, wherein said stray light rays are generated by the light source but do not reach a respective exit of said at least one primary light guide.

2. The luminous module as claimed in claim 1, wherein each secondary light guide comprises a free end facing which no light source is placed.

3. The luminous module as claimed in claim 2, wherein at least one secondary light guide extends longitudinally along a first axis substantially parallel to the optical axis of the luminous module, and in that said at least one secondary light guide comprises lateral faces that are slightly curved inward in the direction of the first axis.

4. The luminous module as claimed in claim 2, wherein at least one secondary light guide comprises two opposite lateral faces that are concave when viewed from outside the at least one secondary light guide.

5. The luminous module as claimed in claim 2, wherein at least one secondary light guide comprises planar lateral faces.

6. The luminous module as claimed in claim 1, wherein it is arranged so that the image of the exits of the primary light guides associated with the light source forms a strip of light in the projection field, said strip of light forming a segment of a lighting beam.

7. The luminous module as claimed in claim 1, wherein at least one secondary light guide extends longitudinally along a first axis substantially parallel to the optical axis of the luminous module, and in that said at least one secondary light guide comprises lateral faces that are slightly curved inward in the direction of the first axis.

8. The luminous module as claimed in claim 1, wherein at least one secondary light guide comprises two opposite lateral faces that are concave when viewed from outside the at least one secondary light guide.

9. The luminous module as claimed in claim 1, wherein at least one secondary light guide comprises planar lateral faces.

10. The luminous module as claimed in claim 1, wherein at least one secondary light guide comprises a first entrance comprising a free end that is arranged substantially in the same plane as at least certain entrance dioptric interfaces of the primary light guides.

11. The luminous module as claimed in claim 1, wherein at least one secondary light guide comprises a free end that is offset longitudinally with respect to at least certain of the entrance dioptric interfaces of the primary light guides.

12. The luminous module as claimed in claim 1, wherein the projecting assembly comprises a primary lens and a secondary lens that is placed away from and downstream of said primary lens, the primary lens receiving the rays that exit from the exits of the primary light guides and the rays that exit from the exit of the secondary light guide or that exit from the exits of the one or more secondary light guides and sending them to the secondary lens.

13. The luminous module as claimed in claim 12, characterized in that the primary lens, the primary light guides and the one or more secondary light guides are made of the same material and integrally formed so as to form a one-piece optical part.

14. The vehicle luminous module as claimed in claim 1, wherein the projecting assembly comprises a single lens that converges to be level with the focal region so as to image the exits of the primary light guides, and in that the projecting assembly, the primary light guides and the one or more secondary light guides are made of the same material and integrally formed into a single part.

15. The vehicle luminous module as claimed in claim 1, wherein it comprises a plurality of light sources, said light sources being arranged facing the entrance dioptric interfaces of all or some of the primary light guides.

16. A vehicle lighting device, wherein it comprises a luminous module as claimed in claim 1.

17. The luminous module as claimed in claim 1, wherein at least one of the one or more secondary light guides, which is called a first secondary light guide, is placed between two primary light guides.

18. The luminous module as claimed in claim 1, wherein at least one of the one or more secondary light guides, which is called a second secondary light guide, is placed at one end of said horizontal row.

19. A vehicle luminous module intended to generate a light beam along an optical axis, and comprising: primary light guides each comprising an entrance dioptric interface and an exit; a light source arranged facing an entrance dioptric interface; a projecting assembly comprising a focal region and an exit member, said projecting assembly being arranged so that rays of light passing through said focal region and reaching the exit member are imaged in a projection field downstream of said projecting assembly, wherein the exits of the guides being arranged level with the focal region; and one or more secondary light guides distinct from the primary light guides, and arranged so as to deviate light rays generated by the light source so that said light rays do not reach the exit member, deviate said light rays to spread said light rays in said projection field, or both deviate said light rays so that said light rays do not reach the exit member and deviate said light rays to spread said light rays in said projection field, wherein the primary light guides and the one or more secondary light guides are placed in a same horizontal row, and in that at least one of the one or more secondary light guides, which is called a first secondary light guide, is placed between two primary light guides.

20. A vehicle luminous module intended to generate a light beam along an optical axis, and comprising: primary light guides each comprising an entrance dioptric interface and an exit; a light source arranged facing an entrance dioptric interface, a projecting assembly comprising a focal region and an exit member, said projecting assembly being arranged so that rays of light passing through said focal region and reaching the exit member are imaged in a projection field downstream of said projecting assembly, wherein the exits of the guides being arranged level with the focal region; and one or more secondary light guides distinct from the primary light guides, and arranged so as to deviate light rays generated by the light source so that said light rays do not reach the exit member, deviate said light rays to spread said light rays in said projection field, or both deviate said light rays so that said light rays do not reach the exit member and deviate said light rays to spread said light rays in said projection field, wherein the primary light guides and the one or more secondary light guides are placed in a same horizontal row, and in that at least one of the one or more secondary light guides, which is called a second secondary light guide, is placed at one end of said horizontal row.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other features and advantages of the invention will become apparent on reading the following detailed description of non-limiting examples, for the comprehension of which reference should be made to the appended drawings, in which:

(2) FIG. 1 illustrates a perspective view in a direction from upstream to downstream of a luminous module according to one exemplary embodiment of the invention;

(3) FIG. 2 illustrates a view from above of an optical part comprising light guides and a primary lens, said optical part forming part of the luminous module of FIG. 1;

(4) FIG. 3 illustrates a schematic view of a horizontal cross section of the optical part of FIG. 2;

(5) FIG. 4 illustrates a perspective view in a direction from upstream to downstream of the optical part of FIG. 2;

(6) FIG. 5 illustrates a rear portion of a prior-art optical part, which part is similar to the optical part of FIG. 2, but which comprises only primary light guides; FIG. 5 also illustrates, schematically, the traces of light rays emitted by two elementary light sources;

(7) FIG. 5A illustrates the image comprising a strip of light generated by a luminous module comprising the optical part of FIG. 5, and a first image region of stray light rays; said image takes the form of isolux curves projected onto a vertical screen, especially at a distance of 25 meters in front of a luminous module comprising the optical part of FIG. 5;

(8) FIG. 5B illustrates the same image with the strips of light as FIG. 5A and shows a second image region of stray light rays;

(9) FIG. 6 illustrates a rear portion of the optical part of FIG. 2 and light beams emitted by two elementary light sources;

(10) FIG. 6A illustrates the image comprising a strip of light generated by the luminous module of FIG. 1, namely the luminous module comprising the optical part of FIG. 2, and a first image region of stray light rays; said image takes the form of isolux curves projected onto a vertical screen, especially at a distance of 25 meters in front of the luminous module of FIG. 1;

(11) FIG. 6B illustrates the same image with the strips of light as FIG. 6B and shows a second image region of stray light rays.

DETAILED DESCRIPTION

(12) With reference to FIG. 1 and FIG. 2, a luminous module 1 according to one exemplary embodiment of the invention is intended to generate a light beam in the direction of an optical axis I. The luminous module 1 comprises a plurality of light guides 10, a primary lens 5 and a secondary lens 6.

(13) The light guides 10 may be divided into two categories, namely primary light guides 2 and secondary light guides 3. The primary light guides 2 are intended to shape a light beam emitted by at least one light source into a pencil beam output from these primary light guides 2. Each primary light guide 2 comprises an entrance dioptric interface 20 and an exit 29.

(14) In the illustrated example, a light source 9, and especially a light-emitting diode 9, is placed opposite each entrance dioptric interface 20. Therefore, here, the number of diodes is equal to the number of primary light guides. In another example, the number of diodes may be lower than the number of primary light guides.

(15) The secondary light guides 3 are only designed to refract and deviate stray light rays. By stray light rays, what is meant is rays that are generated by a light source placed upstream of a primary light guide 2 but that do not enter into said primary light guide 2, or that exit via one of the lateral faces of this primary guide 2 before reaching its exit. The secondary light guides 3 each comprise an exit 39 and a free end 30. No light source is placed facing the free end 30 of each of the secondary light guides 3. These secondary light guides 3 will be described in detail later on in the description.

(16) In the remainder of the description, for the sake of readability, the terms “primary guides”, “secondary guides”, “stray rays” and “beam” will be used instead of “primary light guides”, “secondary light guides”, “stray light rays” and “light beam”, respectively.

(17) In the illustrated example, the primary lens 5 is a biconvex lens comprising, here, at the front, a main downstream face 51 and, here, at the rear, a main upstream face 52. The set of secondary and primary light guides protrudes toward upstream from this main upstream face 52.

(18) The secondary lens 6 is placed away from and downstream of the primary lens 5, so as to receive the rays that exit from the main downstream face 51 of said primary lens 5. The secondary lens 6 here comprises, at the front, a secondary downstream face 61, and, at the rear, a secondary upstream face 62. In FIG. 1, the secondary upstream face 62 shown is planar, but it may be slightly convex when viewed from outside the lens 6.

(19) The primary lens 5 and the secondary lens 6 are arranged so as to form a projecting assembly 4 having a focal region F that is level with, or that even conforms to, the main upstream face 52 of the primary lens 5. In this way, the light rays output from the primary and/or secondary guides are imaged by the projecting assembly 4 while minimizing optical field aberrations.

(20) With reference to FIG. 2, six light guides, namely four primary guides 2 and two secondary guides 3, are illustrated. All guides are placed in a horizontal row 11.

(21) Three primary guides 2 are placed side by side and are called, in order from left to right in FIG. 2, the first, the second, and the third primary guide 21, 22 and 23, respectively. The fourth primary guide 24 is placed at a right end 110 of the horizontal row 11. Each of the primary guides 2 comprises an entrance dioptric interface 20 and an exit 29. One elementary light source 9, here a light-emitting diode or LED, is placed in front of each entrance dioptric interface 20.

(22) A first secondary guide 31 is placed between the third and fourth primary guides, 23 and 24. A second secondary guide 32 is placed at a left end 111 of the horizontal row 11. Each of the secondary guides 3 comprises here, at the front, an exit 39, and here, at the rear, a free end 30.

(23) As described above, the exits of the primary and secondary guides 20 and 30 are arranged on the main upstream face 52 of the primary lens 5. The projecting assembly 4 is configured so that the focal region F includes this main upstream face 52 of the primary lens 5 so as to project to infinity any ray that exits from the primary and secondary guides 2 and 3 via their exit 29, 39.

(24) Consequently, the primary lens 5 receives the rays that exit from the exits of the primary guides 2 and the rays that exit from the secondary guides 3. The primary lens 5 then sends them to the secondary lens 6.

(25) Here, the focal region F has a curved surface that passes through the exits 29 of the primary guides 2 and the exits 39 of the secondary guides 3. The focal region F is illustrated in FIG. 3.

(26) In this example, the six light guides 21 to 24, 31, 32 and the primary lens 5 are formed into a single one-piece optical part 7.

(27) This one-piece optical part 7 comprises lateral fins 71 each comprising one attachment foot 72. The latter is intended to be affixed to a holder (not illustrated in the figures). The attachment feet 72 are fastened, in particular by screwing, to the holder in order to keep the single-piece optical part 7 in position in the luminous module 1.

(28) In FIG. 3, a horizontal cross section of the one-piece optical part 7 is illustrated. Horizontal cross sections of the primary guides 21 to 24 and secondary guides 31, 32 may therefore be seen therein.

(29) In particular, the first secondary guide 31 extends longitudinally parallel to the optical axis of the luminous module. The longitudinal axis of the first secondary guide 31 is called the first axis I1. The first secondary guide 31 comprises two lateral faces 315 that are slightly curved inward in the direction of the first axis I1. In other words, the lateral faces 315 of the first secondary guide 31 are concave faces, when viewed from outside said first guide 31. In other words, the lateral faces 315 of the first secondary guide 31 are convex when viewed from inside the secondary guide 31, i.e. considering the path of the light rays propagating inside said first secondary guide 31.

(30) In this example, the free end 310 of the first secondary guide 31 is substantially coplanar with the entrance dioptric interfaces 20 of the primary guides 2.

(31) As for the second secondary guide 32, the latter comprises planar lateral faces 325. Furthermore, the free end 320 of the second secondary guide 32 is offset longitudinally to downstream with respect to the entrance dioptric interfaces 20 of the primary guides 2.

(32) Here, the length of the two secondary guides 3 and the shape of all their faces, and in particular their lateral faces, are defined so as to intercept and deviate the rays creating the stray light. A shape other than that shown in the figures could therefore be employed. In particular, the shapes that apply to the first secondary guide may also apply to the second secondary guide. Conversely, the shapes that apply to the second secondary guide may also apply to the first secondary guide.

(33) FIG. 4 shows the rear of the primary and secondary guides 2, 3. Here, the primary guides 2 each have an upper face 27 that curves downward slightly. The entrance dioptric interface 20 of each of these guides 2 has, here, a curved surface that is slightly inclined with respect to vertical.

(34) As regards the first secondary guide 31, in this example, the free end 310 of said first guide 31 is composed of a plurality of facets, here two in number, namely an upper facet 311 and a lower facet 312. The lower facet 312 of the free end 310 is located substantially in the same plane as the entrance dioptric interfaces 20 of the primary guides 2. The lower facet 312 is therefore also slightly inclined with respect to the vertical.

(35) Unlike the first secondary guide 31, the free end 320 of the second secondary guide 32 comprises a single facet 321 that is parallel to the vertical direction. The second secondary guide 32 therefore has the shape of a truncated pyramid with the exit forming the large base and the free end the small base.

(36) FIGS. 5, 5A, 5B, 6, 6A and 6B, which are described below, further explain the operation and the technical advantage of the secondary guides 31, 32 in the luminous module 1 according to one exemplary embodiment of the invention, with respect to a luminous module without any secondary guides.

(37) With reference to FIG. 5, an optical part 8 similar to the optical part 7 shown in FIG. 2 and FIG. 6 is illustrated. However, the optical part 8 of FIG. 5, which is called the comparative optical part 8, does not comprise any secondary guides. It comprises only primary guides that, however, are the same in number and in the same arrangement as those in FIG. 2. The primary guides of the comparative optical part 8 have therefore been designated with the same references as those of the primary guides of the optical part 7 shown in FIG. 2 and in FIG. 6.

(38) Two elementary light sources, here two LEDs, are placed in front of the second primary guide and the third primary guide, respectively. The LED 92 placed opposite the entrance dioptric interface 220 of the second primary guide 22 is called the second LED 92 below, whereas the LED 93 placed opposite the entrance dioptric interface 230 of the third primary guide 23 is called the third LED 93.

(39) In FIG. 5, beams emitted by these two LEDs 92 and 93 are also illustrated.

(40) More precisely, the second LED 92 emits a beam a main portion of which, containing most of the rays of this beam, propagates inside the second primary guide 22. This main portion of the beam is called the primary second beam 221 below. This primary second beam 221 propagates through the second primary guide 22 until it reaches the exit 229 of said guide 22, and then the focal region F. The primary second beam 221 is thus imaged by the projecting assembly 4.

(41) The image of the primary second beam 221 forms a pixel 224 with a slightly rectangular shape. This pixel 224 is called the second pixel 224 and is illustrated in FIG. 5A and in FIG. 5B.

(42) It will be noted that the image of the exits of light guides 2, is inverted with respect to their structural arrangement. Specifically, the image of the beams output by the second primary guide 22 is located to the right in FIGS. 5A and 5B, whereas the image of the beams output by the third primary guide 23 is located to the left in FIGS. 5A and 5B. However, structurally, the second primary guide 22 is located to the left of the third primary guide 23, with respect to the direction of emission of the light.

(43) Consequently, the image of the primary second beam 221, which here forms the second pixel 224, is the pixel located to the right in FIG. 5A and in FIG. 5B.

(44) The beam emitted by the second LED 92 comprises yet another beam portion, called the secondary second beam 222. Unlike the primary second beam 221, the secondary second beam 222 does not enter into the second primary guide 22 and is emitted rightward with respect to the direction of emission of the light, i.e. here also rightward in FIG. 5. The secondary second beam 222 passes by refraction laterally through the third primary guide 23. It thus exits the third primary guide 23 via the right lateral edge 235 thereof and is divided into two portions.

(45) A first portion 227 of the secondary second beam 222 reaches the focal region F. A second portion 225 of the secondary second beam 222 enters by refraction into the fourth primary guide 24 before reaching the focal region F.

(46) Therefore, the first and the second portions 227 and 225 of the secondary second beam 222 are also imaged by the projecting assembly 4.

(47) The image of the first portion 227 of the secondary second beam 222 is illustrated in FIG. 5B. It forms a light spot 28 with an irregular shape. In other words, this spot 28 forms a stray image in the image of the beam generated by the luminous module. For the sake of legibility of the figures, a dashed arrow M has been shown to indicate the correspondence between the secondary second beam 222, or more precisely, the first portion 227 thereof, and its on-screen image in FIG. 5B. The spot 28 is located, here, to the left of the second and third pixels 224, 234 in FIG. 5B.

(48) Likewise, the image of the second portion 225 of the secondary second beam 222 will form a stray image in the image of the beam generated by the luminous module.

(49) Thus, the secondary second beam 222 is a beam of stray light rays.

(50) The same effect arises with the third primary light guide 23 and the third LED 93.

(51) As illustrated in FIG. 5, the third LED 93 emits a beam a main portion of which containing most of the rays of the beam propagates the entire length of the third primary guide 23 to then reach the exit 239 and then be projected downstream by the projecting assembly 4. This main portion of this beam is called the primary third beam 231 below.

(52) The image of the third primary beam 231 is a pixel 234 located to the left in FIGS. 5A and 5B. This pixel is called the third pixel 234. The latter has a similar shape to the second pixel 224, namely a substantially rectangular shape.

(53) Thus, the second pixel 224 and the third pixel 234, which are placed side by side, form one portion of a strip of light that the luminous module 1 is capable of generating. The strip of light may be turned on in addition to other basic light segments to form a lighting and/or signaling beam.

(54) The beam emitted by the third LED 93 also comprises another beam portion, called the secondary third beam 232. This passes beside the third primary guide 231 and to the left. The secondary third beam 232 enters into the second primary guide 22 and passes through the latter transversely. It then exits from the second primary guide 22 via its left lateral edge 226, further passes by refraction through the first primary guide 21, and then is directed to the focal region F.

(55) The secondary third beam 232 is therefore imaged by the projecting assembly 4. Its image is illustrated in FIG. 5A. It is a spot 29 of an irregular shape, located on the right side of the second and third pixels 224 and 234 in FIG. 5A.

(56) To facilitate identification, an arrow N shows the correspondence between the secondary third beam 232 and its on-screen image in FIG. 5A.

(57) The secondary third beam 232 is also considered to be a beam of stray light rays.

(58) The presence of the light spots 28 and 29 due to the secondary second beam 222 and the secondary third beam 232 is detrimental to the quality of the beam generated by the luminous module comprising this optical part 8.

(59) Specifically, these spots 28 and 29 may add additional light intensity to the pixels of neighboring guides, i.e. pixels that are generated by guides located on either side of the second primary guide 22 and/or the third primary guide 23. Thus, the value of the light intensity, measured where these spots 28 and 29 and the pixel superpose, generates visual discomfort.

(60) Furthermore, these light spots 28, 29 prevent the pixels formed by the neighboring light guides from being completely turned off. Specifically, when the light sources placed facing neighboring guides are turned off, the corresponding pixels are also turned off. However, if the second and third LEDs 92 and 93 remain on, the beams of stray rays 222, 232 persist. Thus, the light spots 28, 29 remain turned on in the location of the pixels of the neighboring guides, which however are turned off.

(61) In addition, these light spots 28, 29 may be located in a region in which it is not desired to have light, and especially in a location in which another followed or on-coming vehicle is present. There may therefore be residual light, which may cause glare to an on-coming driver or a driver of a followed vehicle.

(62) In light of these disadvantageous effects of stray rays, the applicant proposes a luminous module 1 such as illustrated in FIGS. 1 to 4 and 6 and described above. Of course, it is a question of one embodiment among many other embodiments that are possible while remaining within the scope of the invention.

(63) FIGS. 6, 6A and 6B, which are described below, will allow the operation and the advantageousness of the luminous module according to the invention as described above to be better understood.

(64) With respect to the optical part 8 of FIG. 5, the optical part 7 of FIG. 6 in addition comprises the first secondary guide 31 and the second secondary guide 32.

(65) The optical part 7 of FIG. 6 still comprises the second and third LEDs 92 and 93, and the same primary guides 21 to 24 as those of FIG. 5. The second and third primary guides 22 and 23 thus form the second and third pixels 224 and 234, respectively.

(66) As in the previous case, the second pixel 224 is on the right in FIGS. 6A and 6B whereas the third pixel 234 is on the left in the same figures.

(67) As regards the first secondary guide 31, the latter receives light rays passing from the second LED 92 rightward with respect to the direction of emission of the light, i.e. here also rightward in FIG. 6. More precisely, the first secondary guide 31 receives, here, the secondary second beam 222 emitted by the second LED 92.

(68) The lateral faces 315 of the first secondary guide 31 are curved to increase the effect of deviation of the rays. Inside the first secondary guide 31, the rays of the secondary second beam 222 are reflected multiple times so that, on exiting from said first guide 31, the rays are multidirectional and therefore do not form a collimated beam. Consequently, the image of the light rays exiting from the first secondary guide 31 is spread in the image of the beam obtained on the screen. Where the spot 28 appeared in FIG. 5B, now only a small low-intensity spot 41 appears.

(69) Thus, the first secondary guide 31 decreases the concentration of the stray light.

(70) As regards the second secondary guide 32, the latter receives stray rays propagating leftward with respect to the direction of emission of the light, i.e. here also leftward in FIG. 6. Here, the second secondary guide 32 receives rays emitted by the third LED 93, or more precisely the rays of the secondary third beam 232.

(71) The rays of said secondary third beam 232 are reflected inside the second secondary guide 32 so as to form the various beam portions listed below.

(72) A first portion 326 of these rays is reflected back to the side from which they came, i.e. toward the third primary guide 23.

(73) A second other portion 327 of these rays, as indicated by the line K in FIG. 6, is diverted radially outward from the place where they previously struck the focal region F, and hence away from the interior of the secondary lens 6. Thus, they are transmitted by the primary lens 5 but do not reach the secondary upstream face 62 of the secondary lens 6.

(74) Specifically, the secondary downstream face 61 forms the exit member. A region allowing the rays to reach it is the space immediately in front of the secondary downstream face 61. Another region allowing the secondary downstream face 61 to be reached is the passage through the secondary upstream face 62. Here, the second portion 327 of the stray rays are deviated so as to pass beside the secondary upstream face 62.

(75) Thus, the rays of said portion 327 do not enter into the secondary lens 6, they are therefore not imaged in the projection field of the projecting assembly 4.

(76) A third portion 328 of the rays are reflected a multitude of times in the second secondary guide 32 so that their image is spread over the screen.

(77) In the end, few of the rays that exit from the second secondary guide 32 are able to be imaged by the projecting assembly 4 in such a way as to produce an image of sufficient intensity to be detectable on the screen. A minority of the imaged rays form very small low-intensity spots 42 on the screen. These spots are shown in FIG. 6A.

(78) The second secondary guide 32 therefore limits or prevents the formation of notable stray images in the image of the beam generated by the luminous module 1.

(79) Thus, by virtue of the first and second secondary guides 31 and 32, the luminous module 1 according to the invention and according to the example described above generates a light beam containing very minor stray images, or even a light beam free of stray images. The light beam generated by such a luminous module therefore has an improved quality, this providing a better visibility to the driver.

(80) Of course, it is possible to make many modifications to the invention without departing from the scope thereof.

(81) It is possible for a module to contain solely one or more than one secondary guide(s) on one edge or solely one or more than one secondary guide(s) between 2 primary guides or even one or more than one secondary guide(s) of each type.

(82) Depending on the desired deviations, the lateral faces of the secondary guides may be planar, concave or convex, irrespectively of whether they are at the end or between the primary guides.

(83) The free edges of the secondary guides may be at least partly coplanar with the entrance surfaces of the primary guides or have different shapes.

(84) The secondary guides may be longer or shorter than the primary guides, irrespectively of whether they are at the end or between the primary guides.