FR3090815A1 - FIXING AN OPTICAL GUIDE IN A LIGHT MODULE - Google Patents

Abstract

FIXING OF AN OPTICAL GUIDE IN A LIGHT MODULE The invention relates to a light module (2), in particular for a motor vehicle, comprising an optical guide (6) made of transparent or translucent material, extending in a main direction, with a light entry area, a main face (6.2) for guiding the light with reliefs (6.4) capable of making said light emerge transversely and a terminal transverse face (6.1) at an end opposite the area of Entrance ; an elongated housing (4) receiving the optical guide (6); where the end transverse face (6.1) is fixed to the housing (4) with opaque glue (18). Figure for the abstract: Figure 2

Description

Description

Title of the invention: FIXING OF AN OPTICAL GUIDE IN A LIGHT MODULE

The invention relates to the field of lighting and light signaling, in particular for a motor vehicle. More particularly, the invention relates to the field of lighting and light signaling by means of an optical guide.

In the field of lighting and signaling of motor vehicles, it is increasingly common to use optical guides. Indeed, these have the advantage of being able to take a wide variety of geometric shapes and to provide an illuminating surface even in areas that are difficult to access from 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, in particular by proposing complex shapes to lighting and / or signaling devices.

The published patent document ER 2 996 649 A1 discloses a light module comprising a housing containing a support and an optical guide housed in the support in question. The support and the light guide both extend in a main direction. The support has a cross section forming an open cavity receiving the optical guide and with means for fixing said guide. The latter comprises one or more longitudinal ribs on an upper portion of the guide and engaging with the fixing means. These form elastically deformable hooks. A cover is placed on the optical guide support assembly in order to form a window for the light emerging transversely from said guide. This construction is advantageous in that the mounting of the optical guide on the support is facilitated. The window formed by the cover is dimensioned to hide the limit areas of the optical guide so as to avoid making visible certain light inhomogeneities in the guide, in particular at the rib. For this purpose, the ends of the guide must be far from the lateral limits of the window so that the inhomogeneities which are created there are not visible. In applications where space is limited, in particular according to the main direction of the guide, this teaching is not satisfactory.

The invention aims to overcome at least one drawback of the above-mentioned state of the art. More particularly, the invention aims to provide an elongated light module which is particularly compact and has good light homogeneity.

The invention relates to a light module, in particular for a motor vehicle, comprising an optical guide made of transparent or translucent material, extending in a main direction, with a light entry zone, a main face of guiding the light with reliefs capable of passing said light transversely and a transverse end face at an end opposite to the entry zone; an elongated housing receiving the light guide; remarkable in that the end transverse face is fixed to the housing with opaque glue.

According to an advantageous embodiment of the invention, the opaque glue has an absorbance greater than 1 for wavelengths between 390 nm and 750nm.

According to an advantageous embodiment of the invention, the opaque glue comprises pigments selected from the following list: carbon black, iron oxide, carbon black, smoke black.

According to an advantageous embodiment of the invention, the housing comprises opaque walls serving as support for the optical guide and an opening or a window intended to be traversed by the light emerging transversely from said guide, the terminal transverse face and the opaque glue being hidden by at least one of the opaque walls.

According to an advantageous embodiment of the invention, the terminal transverse face is opposite one of the opaque walls of the housing, said wall forming a bend around said face and delimiting the opening or the window.

According to an advantageous embodiment of the invention, the window is made of transparent or translucent material integrally formed with at least one opaque wall. Advantageously, the housing is produced by co-injection of opaque plastic and transparent plastic, the opaque material then forming the opaque walls and the transparent material forming the window.

According to an advantageous embodiment of the invention, said module further comprises a support extending in the main direction of the optical guide, with a cross section forming an open cavity receiving said guide. Advantageously, the open cavity has a coated U-shaped profile.

According to an advantageous embodiment of the invention, the optical guide comprises on the main guide face, at a position adjacent to the terminal transverse face, a hook forming an opening with an opposite direction from said face, and engaging with the support in said direction. The engagement of the hook with the support makes it possible to ensure a precise positioning of the terminal transverse face with respect to the housing and hence, a controlled thickness of glue.

According to an advantageous embodiment of the invention, the optical guide comprises on the main guide face, at the end opposite to the terminal transverse face, at least one boss with a transverse surface in abutment with the support in the direction of the terminal transverse face.

According to an advantageous embodiment of the invention, the at least one boss comprises another transverse surface in abutment with the support in the direction opposite to the terminal transverse face.

According to an advantageous embodiment of the invention, the optical guide and the support are configured so that the optical guide can be placed in the open cavity of said support by engaging the hook with the support and then gradually inserting by clipping said guide in said cavity to the end opposite to the terminal transverse face.

According to an advantageous embodiment of the invention, the light entry area of the optical guide is formed by a transverse entry face at the end opposite the end transverse face, the support comprising at said end a portion forming a reference bearing surface for a plate supporting one or more light sources.

According to an advantageous embodiment of the invention, the portion of the support forming the support surface forms a pin extending in the main direction of the optical guide.

According to an advantageous embodiment of the invention, the optical guide comprises on the main guide face, in a middle position between the two ends of said guide, a longitudinal rib engaging by clipping with a flexible portion of the support.

According to an advantageous embodiment of the invention, the support comprises, on a rear face, a longitudinal wall forming with two longitudinal walls of the housing two longitudinal cavities open towards the rear each receiving a bead of adhesive material ensuring attachment and a seal between said support and said housing. At least one of the beads of adhesive material being in contact with the opaque glue ensuring the fixing of the terminal transverse face to the housing. The cords of adhesive material are in contact with the interior faces of the longitudinal walls of the housing.

The measures of the invention are advantageous in that they allow an efficient assembly to be carried out, essentially in that the fixing is stable and precise, the fixing requires very little space at the terminal end of the optical guide, and the fixing avoids problems of return by reflection of light in the optical guide, likely to generate inhomogeneities. Clipping in the middle or intermediate zone of a rib with the support ensures fast, simple and stable attachment. Similarly, the attachment to the light entry end is quick, simple and ensures exact longitudinal positioning, capable of leaving an adequate space between the terminal transverse face and the wall of the housing opposite said face.

Other features and advantages of the present invention will be better understood on the basis of the description and the drawings, among which:

[Fig.l] is a sectional view of a light module according to the invention.

[Fig-2] is a perspective view of the terminal end of the optical guide and the support of the light module of Figure 1.

[Fig.3] is a longitudinal sectional view of the terminal end of the light module of Figure 1.

[Fig.4] is a perspective view of the optical guide and the support of the light module of Figure 1, cut to an intermediate position.

[Fig.5] is a sectional view of Figure 4.

[Fig. 6] is a perspective view of the light entry end of the light guide and of the light module support of Figure 1.

[Fig.7] is a longitudinal sectional view of the light inlet end of the light module of Figure 1.

Figures 1 to 7 illustrate a light module according to the invention.

Figure 1 is a sectional view of the light module. The latter 2 is generally elongated in a main direction, it being understood that this direction is not necessarily perfectly straight, namely that it can have a curved profile or at least with curves. The light module 2 essentially comprises a housing 4, an optical light guide 6 and a support 8 for the optical guide 6, said guide and said support being housed in the housing 4. The housing 4 comprises several opaque walls 4.1, 4.2 and 4.4 and a transparent wall 4.3. The latter is advantageously entirely formed by the other walls, by co-injection of several separate materials, one of which is transparent and forms the wall 4.3. As can be seen, the latter forms a window on a front face of the light module 2 so as to be traversed by the light emerging transversely from the optical guide, thus forming a light surface.

In this embodiment of the invention, a cap 10 of non-transparent material is arranged along the upper edge of the housing 4. It also covers the upper wall 4.2 of the housing 4. It can be made of finishing material as for example with a chrome appearance or a matte black appearance.

The light module 2 is fixed in this case to a support wall 12 potentially forming part of the vehicle.

More particularly, the housing 4 has a section in the shape of a coated U, the base of which forms the front face and the opening is directed towards the rear. The optical guide is made of transparent or translucent material, of tubular shape with a generally circular or at least generally rounded section, such as for example oval. It is housed on the support 8 which is itself fixed to the housing 4. The support 8, similar to the housing, is elongated in the longitudinal direction of the light module. It has a cross section with a main portion 8.1 U-shaped lying with the opening facing forward, facing the transparent wall 4.3. This portion

8.1 forms an open cavity 8.2 housing the optical guide 6. The cross section of the support 8 can also include a bent wall portion 8.3 ensuring abutment contact with the upper wall 4.2 of the housing 4. It can also include a rear longitudinal wall 8.4 forming with the intermediate wall 4.4 and the upper wall 4.2 of the housing 4 two longitudinal cavities 4.5 and 4.6 open towards the rear each receiving a bead of adhesive material 14 ensuring attachment and sealing between said support and said housing.

Figures 2 and 3 illustrate the terminal end of the light module 2, that is to say the end opposite to the light source, where the light ends its path along the optical guide. Figure 2 is a perspective view of the optical guide and the support while Figure 3 is a longitudinal sectional view of the module.

In Figure 2, it can be seen that the optical guide 6 has a terminal transverse face 6.1 and, on its main guide face 6.2, a hook 6.3 forming an opening engaging with the support 8, at a side face 8.5 of said support. This hook 6.3 is adjacent to the terminal transverse face 6.1. Its opening is oriented opposite the terminal transverse face 6.1, so as to make with the support 8 a retainer in the direction opposite to the terminal transverse face 6.1, namely that a pull on the optical guide 6 in this direction maintains the engagement of the hook 6.3 with the support 8 without displacing it further.

The optical guide 6 comprises on a rear zone of the main guide face 6.2, forming a diopter, reliefs 6.4 configured to bring out the light propagating in the optical guide transversely. Such reliefs are in themselves well known to those skilled in the art.

Still in Figure 2, we can observe the presence of a fastening element 16 shock absorber, more commonly referred to by the English expression "silent block". It is made of elastomeric material and in this case comprises an orifice receiving a pin extending from a rear face of the support 8 and an outer generally cylindrical surface intended to be received in a corresponding housing, said housing advantageously being on the motor vehicle.

In Figure 3 we can observe the pin 8.6 of the support 8, engaging in the shock absorbing fixing element 16. It is also observed that the terminal transverse face 6.1 is opposite a opaque side wall 4.7 of the housing 4, but at a distance from said wall. Opaque glue 18 is placed between this face 6.1 and this wall 4.7. It performs a dual function, namely to fix the optical guide 6 and the support 8 to the housing 4, and to avoid unwanted light reflections liable to generate over-lighting and, consequently, highlighting near this end, at the level of the transparent window 4.3. In other words, the opaque nature of the adhesive 18 makes it possible to absorb a major part of the light rays arriving at the terminal transverse face 6.1, which makes it possible to avoid reflections returning light in the opposite direction, liable to generate inhomogeneities, in particular near the terminal end.

Still in connection with Figure 3, we can see that the side wall 4.7 of the housing, opposite which is located the terminal end of the optical guide 6, forms a bend forward, so as to s' extend longitudinally over a reduced portion, in line with the transparent window 4.3. The longitudinal extent of the wall is such that the said wall hides the adhesive 18 and the terminal transverse face 6.1 of the optical guide.

Still in relation to FIG. 3, it is interesting to note that the lateral face 8.5 of the support 8, surrounding the optical guide 6 at the level of the terminal transverse face 6.1, is also in contact with the adhesive 18.

The opacity of the adhesive 18 is obtained by adding pigments, such as carbon black, iron oxide, carbon black and / or smoke black. The glue 18 can have an absorbance greater than 1 for wavelengths between 390 nm and 750 nm. An example of a commercially available opaque glue is Dow Corning® glue called "Q3-3636 Catalyst Special Black".

Figures 4 and 5 illustrate an intermediate area of the light module 2, that is to say between the terminal end illustrated in Figures 2 and 3, and the other end where the light enters the light guide. Figure 4 is a perspective view of the optical guide and the support where they are cut while Figure 5 is a view of the section in question.

On this intermediate zone, the optical guide 6 comprises on the main guide face 6.2, a rib 6.5. This is advantageously located on an upper zone of said face. This rib is engaged in a groove 8.7 formed in the support 8. The groove is delimited towards the front by a wall portion 8.8 of the support, said portion being advantageously deformable so as to allow insertion of the optical guide towards the bottom of the 8.2 cavity of the support 8. During this insertion, the upper face of the rib 6.5 contacts the lower face of the deformable wall portion 8.8, causing it to deform upwards, allowing the insertion of the optical guide 6 up to 'that the rib 6.5 passes beyond said wall portion. The latter then returns to its initial position and thus blocks the rib 6.5.

Figures 6 and 7 illustrate the light input end of the light module 2, that is to say the opposite end to the terminal end, where the light emitted by a light source enters the optical guide in order to propagate there. Figure 6 is a perspective view of the optical guide and the support while Figure 7 is a longitudinal sectional view of the module.

The optical guide 6 comprises, at the light inlet end and on the main light guide face 6.1, two bosses respectively forming two transverse surfaces 6.7 and 6.8 in abutment with the support 8. More specifically the transverse surface 6.7 is in abutment with a corresponding surface 8.9 of the support in the direction of the end transverse face, while the transverse surface 6.8 is in abutment with a corresponding surface 8.10 of the support in the direction opposite to the end transverse face. In other words, the two transverse surfaces 6.7 and 6.8 form with the corresponding surfaces 8.9 and 8.10 of the support 8 stops in two opposite directions along the main direction of the optical guide 6 and of the light module in general. They thus make it possible to ensure exact positioning of the optical guide in the main direction. The surface 8.9 of the support is formed on an elastic arm, capable of being deformed when the optical guide 6 is inserted into the cavity of the support 8. The surface 8.10 is itself formed directly on one of the walls of the support 8.

The optical guide 6 comprises a light entry area 6.6 formed in this case by a transverse light entry face 6.9 in front of which is arranged a light source 20. This is advantageously constituted essentially a circuit board 20.1, of the printed circuit type, and one or more light-emitting diodes 20.2. The light source 20, in this case the plate 20.1 of said source, is supported on a support surface 8.11 formed at the end of a pin 8.12 projecting from the support 8. This pin thus serves as a positioning surface from the light source 20. The distance between the light source 20, more particularly light-emitting diodes 20.2, and the transverse light entry face 6.9 is thus controlled.

The mounting of the optical guide 6 on the support 8 operates as follows: the terminal end of the optical guide 6 is put in place in the support 8 by engaging the hook 6.3 with the support 8. The optical guide 6 is then gradually inserted into the cavity of the support 8. At the intermediate zone, the optical guide is pressed towards the bottom of the cavity so that the rib 6.5 is placed in the groove 8.7 of the support. Then the light entry end of the light guide is inserted into the cavity of the support. For this purpose, an adjustment of the position of the optical guide along the main direction may be necessary. In this case, the optical guide 6 is moved longitudinally until the boss forming the transverse abutment surface 6.7 passes beyond the corresponding surface 8.9 on the elastic arm of the support 8. Once this heading is reached, the other transverse surface stop 6.8 is in contact with the corresponding surface 8.10 of the support 8. The longitudinal position of the optical guide 6 is then reached with precision. The opaque glue can then be applied between the finished transverse face 6.1 and the opaque wall 4.7 of the housing 4. Also, the light source 20 can be positioned against the bearing face

8.11 of the pawn 8.12.

It follows from the above a multiple fixing, stable and easy to implement, and this in a very limited volume. Thanks to this compactness, the module can be implemented in severe space conditions. As an example, the module can be mounted essentially horizontally on a motor vehicle grille, for example with such a module on each side of a central escutcheon. The latter can house the light sources for the illumination of said escutcheon but also of the light modules in question. By an adequate dimensioning of the reliefs on the rear zone of the main guide face of the optical guide, the opening or the window of the housing through which the light exiting from said guide then exhibits good light homogeneity, and this up to its terminal end .

Claims (1)

Claims [Claim 1] Light module (2), in particular for a motor vehicle, comprising: - an optical guide (6) of transparent or translucent material, extending in a main direction, with a light entry zone (6.6), a main light guiding face (6.2) with reliefs (6.4 ) capable of passing said lumen transversely and a terminal transverse face (6.1) at an end opposite to the entry zone (6.6); - an elongated housing (4) receiving the optical guide (6), characterized in that the end transverse face (6.1) is fixed to the housing (4) with opaque glue (18). [Claim 2] Light module (29 according to claim 1, characterized in that the opaque adhesive (18) has an absorbance greater than 1 for wavelengths between 390nm and 750nm. [Claim 3] Light module (2) according to either of Claims 1 and 2, characterized in that the opaque adhesive (18) comprises pigments selected from the following list: carbon black, iron oxide, carbon black, smoke black. [Claim 4] Light module (2) according to one of claims 1 to 3, characterized in that the housing (4) comprises opaque walls (4.1, 4.2, 4.4, 4.7), serving as a support for the optical guide (6) and an opening or a window (4.3) intended to be traversed by the light emerging transversely from said guide, the terminal transverse face (6.1) of said guide and the opaque adhesive (18) being hidden by at least one opaque wall (4.7) among the opaque walls ( 4.1, 4.2, 4.4, 4.7). [Claim 5] Light module (2) according to claim 4, characterized in that the end transverse face (6.1) of the optical guide is opposite the opaque wall (4.7) among the opaque walls (4.1, 4.2, 4.4, 4.7 ) of the housing (4), said wall (4.7) forming a bend around said face and delimiting the opening or the window (4.3). [Claim 6] Light module (2) according to one of claims 4 and 5, characterized in that the window (4.3) is made of transparent or translucent material integrally formed with at least one opaque wall (4.7). [Claim 7] Light module (2) according to one of claims 1 to 6, characterized in that said module further comprises a support (8) extending along the main direction of the optical guide (6), with a cross section forming an open cavity (8.1) receiving said guide. [Claim 8] Light module (2) according to claim 7, characterized in that the optical guide (6) comprises on the main guide face (6.2), at a position adjacent to the end transverse face (6.1), a hook (6.3) forming an opening with an opposite direction from said face, and engaging with the support (8) in said direction. [Claim 9] Light module (2) according to one of claims 7 and 8, characterized in that the optical guide (6) comprises on the main guide face (6.2), at the end opposite to the end transverse face (6.1), at least one boss with a transverse surface (6.7) in abutment with the support (8) in the direction of the terminal transverse face (6.1). [Claim 10] Light module (2) according to claim 9, characterized in that the at least one boss comprises another transverse surface (6.8) in abutment with the support (8) in the direction opposite to the terminal transverse face (6.1). [Claim 11] Light module (2) according to claim 8 and according to one of claims 9 and 10, characterized in that the optical guide (6) and the support (8) are configured so that said guide can be placed in the cavity open (8.1) of said support (8) by engaging the hook (6.3) with the support (8) and then by gradually inserting said guide into said cavity to the end opposite the end transverse face (6.1). [Claim 12] Light module (2) according to one of Claims 7 to 11, characterized in that the area of entry (6.6) of the light from the optical guide (6) is formed by a transverse entry face (6.9) at the end opposite to the terminal transverse face (6.1), the support (8) comprising at said end a portion forming a support surface (8.11) for a reference plate (20.1) supporting one or more light sources (20.2). [Claim 13] Light module (2) according to claim 12, characterized in that the portion of the support forming the support surface (8.11) forms a pin (8.12) extending in the main direction of the optical guide (6). [Claim 14] Light module (2) according to one of claims 7 to 13, characterized in that the optical guide (6) comprises on the main guide face (6.2), at a median position between the two ends of said guide, a longitudinal rib (6.5) engaging by clipping with a flexible portion (8.8) of the support (8). [Claim 15] Light module (2) according to one of claims 7 to 14, characterized in that the support (8) comprises, on a rear face, a longitudinal wall (8.4) forming with two longitudinal walls (4.2, 4.4 ) of the housing (4) two longitudinal cavities (4.5, 4.6) open towards the rear each receiving a bead of adhesive material (14) ensuring a fixing and a seal between said support and said housing.