FR2799265A1 - Motor vehicle head lamp module has transparent plates joined together by 3 - 5 mm spots of adhesive at intervals. - Google Patents

Abstract

The module (1000) has an actual light source and a system (1001) for concentrating the light rays from the source on the end of a light duct (1100) made up of a series of adjacent transparent plates (1110, 1120, 1130) lying in line with the duct's axis (X - X). The plates, which are joined together at intervals by 3 - 5 mm spots of adhesive, have at least one oblique reflective face (1111, 1121) which forms a virtual light source and is positioned so to co-operate optically with dioptric elements (1111a, 1121a). The transparent plates are of glass and are of different lengths, with the upper shortest one attached by a single spot of adhesive to the one below it, and with intermediate plates joined by two spots of adhesive at each end.

Description

The present invention relates generally to motor vehicle headlamps.

It relates more particularly to a projector of the type described in French patent n 96 12972 published under 2 755 210, and French patent application n 97 09210 published under n 766 257, belonging to the Applicant.

This projector comprises a real light source, means for concentrating the light radiation coming from this source on the end of a light pipe comprising a plurality of transparent plates juxtaposed in at least one direction, each transparent plate extending along the longitudinal axis of the light pipe and comprising, less at its end furthest from the real light source, an oblique reflection facet, said facets constituting as many virtual light sources and being arranged so as to cooperate optically with dioptric elements of axis parallel to the direction of illumination so that they project in this direction, images corresponding to the facets.

The assembly of the transparent light duct blades of such a projector is a delicate operation taking into account the number of blades to be assembled, the precise positioning of the reflection facets, and the fragility of said blades preferably made of glass, this fragility being mainly at their edges.

The present invention then proposes a new projector of the aforementioned type, in which there is provided a simple means of prior assembly of the blades together so as to constitute a set of monobloc blades easy to handle to be mounted on a blade support.

More particularly, in the projector according to the invention, the transparent blades are glued together at specific points, each point of glue having a diameter of between approximately 35 mm.

According to a preferred embodiment of the projector in accordance with the invention, the transparent blades having different lengths, the shortest upper transparent blade is glued dot on the lower transparent blade, each intermediate transparent blade being glued on another blade by two glue dots located at each end of said blade.

Said transparent blades are made of glass.

The glue used is advantageously a one-component glue which is crosslinkable to ultraviolet radiation, to humidity or to heat. It can be an epoxy adhesive or a silicone adhesive. The description which follows, with reference to the appended drawings, given by way of nonlimiting examples, will make it clear what the invention consists of, and how it can be implemented.

the accompanying drawings - the figure is a schematic partial perspective view of the principle of a projector according to the invention, - the figure a sectional view in a vertical plane of the projector of Figure 1, - the figure a front view of the end of the light pipe of the projector of the figures and 2, - the figure is a schematic view of a transparent blade inclined so that its front face of light outlet is no longer vertical, - the figure is a schematic view in perspective of a practical embodiment of the headlight type of that shown in Figure 1, and - the figure is a perspective view from above of the mounting plate on which are positioned the transparent blades superimposed headlight of the figure reference to Figures 1 to 4 , we will first of all describe in general principle of the projector according to the invention, then with reference to FIGS. 5 and 6 we will describe a practical embodiment of such a pr injector.

FIGS. 1 to 3 of the present patent application, show a motor vehicle headlight which comprises a real light source 101 and means 102 for concentrating the light radiation coming from this source on the end of a light pipe 200.

means for concentrating the light radiation emitted from the real light source 101, consist essentially of an elliptical reflector or mirror, the light source 101 consisting of the filament or the arc of an automobile lamp, preferably arranged in the axis of the elliptical reflector, at one of its focal points.

luminous flux coming from the real light source 101 is reflected by the elliptical reflector 102 according to a set of rays which converges towards the focal area second focal point of said elliptical reflector.

may provide that the elliptical reflector 102 is provided with an opening (not shown here) constituting a window of light allowing the rays coming directly from the real light source to pass.

In the axis of the elliptical reflector 102 extends the light pipe 200. light pipe 200 comprises a plurality of transparent strips, here of different lengths, juxtaposed in at least one direction, each transparent strip extending along the longitudinal axis of the light pipe 200 and substantially transversely to the direction of illumination E.

In this embodiment, the longitudinal axis of the light pipe extends horizontally.

light pipe 200 here comprises four transparent strips 210 220,, 240, of different lengths, here superimposed in the vertical direction Y transverse to the axis of the light pipe and to the direction of illumination E. Preferably, each strip transparent is made of glass. Each transparent plate 210, 220, 230, 240 has at its end further from the real light source 101, an oblique reflection facet 210a, 220a, 230a, 240a, said facets being arranged so as to cooperate optically with dioptric elements, here lenses not shown, with an axis parallel to the direction of illumination so that these lenses project in this direction images corresponding to the facets.

Indeed, at the front of the optical system thus defined above, there is provided a set of dioptric elements, converging lenses (not shown in Figures 1 to 4) whose axes are substantially parallel to the direction of illumination E The lenses are arranged in an optical cooperation relation with the facets 210a, 220a, 220b, 230a, 240a which are substantially arranged at the focal point of the lenses. Each transparent strip has a light entry face extending transversely to the longitudinal axis of the light pipe. The assembly of the light entry faces of said blades constitutes the light pipe entry face (see FIG. 3). Each transparent blade 210, 220, 230 also comprises a light exit face 211, 221, 231, 241 which, according to the embodiment shown in FIGS. 1 and 2, extends vertically perpendicular to the direction of illumination indicated by the arrow E .

Of course, according to an alternative embodiment shown more particularly in FIG. 4, provision can be made for the light exit face of each transparent strip 250 to have an inclination a, (i relative to the vertical axis therefore an inclination d 'an angle p different from 90 degrees with respect to lighting direction E.

in addition, it is possible, as shown in FIGS. 1 and 2, that one or more transparent plates (s) comprise) other reflection facets 220b, these facets 220b being delimited by recesses of height equal to e, provided in the rear part of each blade, as is the case in particular with the transparent blade 220.

reflection facets 210a, 220a, 220b, 230a, 240a of the light pipe are inclined relative to the direction of illumination E, their inclination being between 35 and 55 degrees, and preferably equal to 45 degrees.

refer for example to the embodiment shown in the figure patent No. 2,514,105 belonging to the Applicant, according to which it can be seen for a refractive index of 1.7, an optimum is reached for a facet angle of 53 degrees relative to to lighting direction E.

particular, according to the embodiment shown in FIG. 4, the transparent strip having an inclination different from 90 degrees relative to the direction of illumination E, necessarily the associated reflection facet presents inclination relative to the vertical different from degrees to reflect beam bright in the direction of illumination.

Advantageously, to avoid losses of refractive light flux, provision may be made for the lateral, front and rear internal faces of each transparent strip to be coated with a reflective coating.

In particular, the interfaces between the transparent plates can be aluminized.

As has already been described in invention patent No. 514 105, a converging lens may be provided disposed opposite the window provided in the elliptical mirror 102 in relation to optical cooperation with the real light source 101 which is substantially at his home.

In addition, one can provide a semi-reflecting mirror disposed second focal point of the elliptical mirror 101 between the light source and the entry of the light pipe 200 formed by the juxtaposition, here the superposition, of the entry faces of the transparent blades constituting it. .

In this case, a converging lens is provided, arranged in the same way as the lenses associated with the facets of the transparent blades, in optical cooperation relation with the semi-reflecting mirror which is substantially disposed at the focal point of this converging lens.

With the above-mentioned arrangement, the light flux coming from the real light source 101, reflected by the elliptical mirror 102, penetrates into the light pipe and into each transparent plate 210, 220, 230, 240 constituting it by their inlet section respective and is reflected therein, in a regime of total reflection, by the facets 210a, 220a, 220b, 230a, 240a associated. The reflected elementary beams are taken up by the lenses (not shown in FIGS. 1 to 4) which project the corresponding light beams towards the front of the projector.

Likewise, the luminous flux intercepted by the semi-reflecting mirror interposed between the light source and the light pipe input is taken up by the associated lens. The direct luminous flux passing through the window of the elliptical mirror is taken up by the associated lens.

With such an arrangement, it is possible to control the illumination of each facet since the flux returning into a transparent strip is necessarily led to the reflecting facet located at the end of said strip. Each transparent strip constitutes an individual light pipe for a facet of the light pipe of the projector according to the invention.

The illumination of each facet can be measured by the illumination dosage of each transparent plate carrying said facet and thus form the final light beam provided.

In projection, each facet with total reflection 210a, 220a, 220b, 230a, 240a, gives on screen, through the corresponding lens an image corresponding to the input flux received by the facet and projected in the direction E, the virtual image given by each facet having a width equal to the side of the corresponding transparent blade entry face and a height equal to the height of the blade or to the height of the offset e (as regards the facet 220b of blade 220).

The different elementary beams merge into a single emission beam and by a judicious arrangement of the axes of the lenses more or less offset relative to the axes of the elementary beams which they intercept, any lighting arrangement can be made, for overall illumination for motor vehicle.

In particular, we can make sure that the images projected in correspondence with the different facets are superimposed or juxtaposed and we can, in the same way superimpose on these images or juxtapose to these images, those which come from the window of the elliptical mirror or of the semi-reflecting mirror.

To make a cut-off beam, as shown more particularly in FIG. 1, covers 301, 302, 303 are provided arranged on the path of certain elementary beams of at least certain facets 210a, 220a, 200b, here on the face before corresponding transparent slats.

According to a variant not shown, provision can be made for these covers to be placed directly on the facets concerned. In addition, according to another variant, it is also possible to provide that certain facets have the profile corresponding to the shape of the desired cut.

In Figure 5, there is shown a headlight 1000 for a motor vehicle, of the same type as that described above.

It comprises an elliptical reflector or mirror 1001, the light source consisting of the filament or the arc of an automobile lamp, preferably arranged in the axis of the elliptical reflector 1001, at one of these focal points.

The light pipe 1100 of the projector 1000 is provided with a plurality of oblique reflection facets 1111, 1121, 1122 and 1131 (see more particularly FIG. 6) which cooperate with a plurality of dioptric elements 1111a, 1a, 1122a, 1131a, here homologous Fresnel lenses, with axes parallel to direction of illumination E.

As can be seen more particularly in the figure, the light pipe 1 is constituted by three transparent blades 1110, 11 1130, here of different lengths, superimposed in the vertical direction transverse to the longitudinal axis X of the light pipe and at the direction of illumination E.

Each transparent slide is made of glass.

Each transparent strip 1110, 1120, 1130, has @ its end furthest from the real light source, an oblique reflection facet 1111, 1122, 1. The intermediate transparent plate also has another reflection facet 1121, delimited by a recess provided in the rear part thereof.

 oblique reflection facets 1111, 1121, 1222, 1131, are inclined relative to the direction of illumination E, their inclination being between 35 and 55 degrees, depending on the positioning of the longitudinal axis of the light pipe relative to the lighting direction.

Each transparent strip has, at its end opposite to the facets, an entry face for the light extending transversely to the longitudinal axis of the light pipe. The set of light entry faces of the transparent blades constitutes the entry face of the light pipe. Each transparent strip further comprises a light exit face which is here a front face 'extending on a longitudinal side of the transparent strip, vertically and substantially perpendicular to the direction of illumination E.

The projector 1000 also includes a reference piece 1200 for mounting said light pipe 1100.

This reference piece 1200 comprises a first generally flat horizontal part 1210, 1220, which extends along the longitudinal axis X of the light pipe 1100 and which defines a horizontal reference plane. The reference part 1200 also includes a second generally flat vertical part 1230, extends perpendicular to said first flat part 1210, 1220 and defines a vertical reference plane.

The transparent blades 1110, 1120, 1130, juxtaposed with the light pipe are mounted in abutment against the first and second planar parts 1210, 1220, 1 of said reference piece 1200, in a position determined along the longitudinal axis X of the pipe of light 1100 so that their oblique reflection facets cooperate with the associated Fresnel lenses 1111a, 1a, 1122a, 1131 so that they project in the direction of illumination images corresponding to the facets at a determined location in the illumination beam .

It should be noted that in a projector with a light guide transparent blades, nothing is provided to ensure the introduction of light at the desired height on the input faces of the transparent blades. The lighting profile at the entrance face of the light pipe is not uniform but has a high concentration over an approximately circular area a few millimeters in diameter which must be centered on the interface of the slats 1110 and 1120. The dispersion of the light on the thickness of the associated blades manufacturing tolerances of the flat glass for the formation of the blades, does not a priori guarantee that this zone with a high level of illumination is correctly positioned relative to this interface, which then penalizes the light beam quality obtained.

The upper face of the intermediate transparent blade 120 of the light pipe is wedged on the internal face of the first horizontal flat part 1220 of the reference piece 1200 and the upper transparent blade 1110 rests on the intermediate blade 1120.

Thus, the interface of these two blades is perfectly positioned in a determined manner with respect to the reference piece 1220 and the indexed mounting of the reflector on the reference piece then makes it possible to overcome the aforementioned drawback.

The reference piece 1200 is here a single piece, but according to a variant embodiment not shown, provision could be made for this reference piece to be produced in several parts assembled together. Its first generally horizontal flat part is an upper part comprising the upper part 1210 and a lower part 1220 horizontal, parallel, and connected by a recess 1250. upper surface of the light pipe 1200 bears against the internal face this first generally flat horizontal part of the reference part. More particularly, the upper face of the shortest transparent blade 11 bears against the internal face of the upper part 1210 of the first horizontal flat part of the reference part, and the upper surface of the projecting part of the transparent blade intermediate 1120 located just below the shortest transparent blade, bears against the internal face of the flat bottom part 1220 of the first horizontal part of the reference piece 1200. The top part of the first horizontal flat part of the reference part has an edge which extends at an angle (relative to the longitudinal axis X) from the recess 1250 to its end situated on the reflector side. angled edge carries a rod which projects in the direction of the light pipe. This rod allows positioning along the longitudinal axis of the light pipe, the transparent blade directly pressing against the high flat part of said reference piece 1200, here the shortest transparent blade 1110.

second vertical flat part 1230 of the reference part 1200 a perforated front part according to a particular profile depending on the length and positioning of the oblique reflection facets of the transparent blades, against which the front light exit faces of the transparent blades of the conduit bear from light.

reference part 1200 comprises a frame, here generally circular in shape for mounting the elliptical reflector 1101 carrying the real light source. The length of the shortest upper strip 1110 of the light pipe is such that the second focal point of the elliptical reflector mounted in a circular frame is located at the end of said upper transparent strip carrying an oblique reflection facet 1111, this in order to obtain a concentration of light on this reflection facet which will give the illumination beam its range.

At the rear of the reference piece 1200 and at its furthest reflective end, holes are provided for fixing on said reference piece 200 a retaining piece 1300.

 Indeed, the projector 1000 here comprises a retaining piece 1300 fixed on the reference piece 1200, bearing against the rear and lower faces of the light pipe 1100 to hold by compression said transparent blades 1110, 1120, 1130 bearing against the first and second flat parts 1210, 1220, 1230 of said reference piece 1200. This compression holding piece 1300 has a base extending along the longitudinal axis X of the light pipe, in a horizontal plane parallel to the horizontal reference plane defined by the first horizontal flat part of the reference part. A vertical upright extends along the rear longitudinal edge of the horizontal base, and is intended to bear against the rear face of the light pipe.

This retaining piece 1300 is fixed to the reference piece 1200 by a system of screws introduced into opposite bores, provided respectively on the retaining piece and on the reference piece.

According to another embodiment, not shown, provision may be made for the retaining piece and the reference piece forming a single piece, the retaining piece then forming only a horizontal return extending from the bottom edge of the flat vertical part of the piece. reference, towards the rear projector. This horizontal return is located below the light pipe to keep the light pipe pressed against the reference planes the reference part.

may be provided in the lighting module 1000, an elastic pressure element not shown here, such as a leaf spring, between the light pipe the first planar part of the reference part. This elastic pressure element can be placed between the internal face of the upper part of the first flat part of the reference part, and the upper surface of the shortest transparent blade 1110. It participates in the compression compression of the transparent blades against the first horizontal flat part of the reference part.

moreover, as shown in more particularly FIG. 5, headlamp 000 comprises a front mounting part 1400 which comprises two horizontal plates 1410, 1420 arranged parallel opposite one another and secured to each other by vertical uprights. Mounting tabs 1430 extend from the vertical uprights of the front mounting piece 1400 and are attached to the reference piece 1200 at each of its ends. The facing internal faces of the base plates 1410, 1420 of the front mounting part 1400 have grooves forming slides for mounting Fresnel lenses 1111a, 1121a, 1122a, 1131a. The grooves provided for mounting Fresnel lenses have a certain orientation relative to the direction of illumination E, and are positioned relative to the second vertical plane part of the reference part, so that the Fresnel lenses mounted in these grooves , the front mounting part being fixed to the reference piece optically cooperate with the oblique reflection facets of the transparent blades mounted in abutment against the reference piece, in order to project an image corresponding to said facets in the direction of illumination.

According to an alternative embodiment not shown, it can be provided that the Fresnel lenses 1111a, 1121a, 1122a, 1131a form a one-piece assembly made integral with the reference piece of the projector by being fixed on a fixing lug extending from said reference part towards the front and towards the top of the projector.

For the production of a cut-off beam, it may be provided in headlamp 1000, covers placed on the path of certain elementary beams of at least certain facets of reflection, between the front face of the transparent blades considered and the associated dioptric elements, said covers being integral with the part before mounting fixed on the reference part in a determined position relative to the latter.

Said covers here not shown and the front mounting part can form a single part. It can also be provided according to another embodiment that these covers are attached to said front mounting part fixed thereto by fixing means.

it should be noted that the reference part 1200, the retaining part 1300 the mounting part 1400 can advantageously be made by aluminum casting. Fresnel lenses 1111a, 1121a, 1122a, 1131a can be made of Poly-N-methylmethacrylimide.

FIG. 6 shows the principle of indexed mounting of the transparent blades 1130, 11 1110 of the projector 1000 shown in FIG. 1.

As shown more particularly in this FIG. 6, there is provided a mounting plate 2000 bearing on a lateral post of the pins 2001, 2002, 2003 for the indexed positioning of the transparent blades 1130, 1120, 1110 along the longitudinal axis X of the light pipe. For this purpose, said rods are placed at locations determined along the longitudinal axis of said plate 2000.

The mounting piece 1300 is positioned on the mounting plate 2000 and then the transparent strips 11 1120, 1130 of the light pipe are superimposed on the retaining piece 1300, in decreasing lengths, each transparent strip 1130, 1120, 1110 being positioned from so that one of the oblique reflection facets 1131, 1121, 1111 abuts against the corresponding positioning rod 2001, 2002, 2003 of the mounting plate 1200. as regards the transparent intermediate blade 1, this is the first facet of oblique reflection 1121 provided on its rear face abuts against the corresponding rod 2002 of the mounting plate 2000.

Advantageously, during the indexed positioning of transparent blades, said blades are glued together at specific locations to form a block of integral blades, positioned in a determined manner with respect to each other.

such a block of blades is easily manipulated to be mounted on the part reference 1200, and better withstands the shocks and vibrations generated during running of the vehicle.

Indeed, the low friction generated by the glass-on-glass contact between different blades of the light pipe constitutes a problem for the impact and vibration resistance of the headlight when the vehicle is in motion, because the overlapping glass blades tend to slide one over the other and no longer play their optical role.

The bonding of the transparent blades together makes it possible to solve the aforementioned problem.

However, the surface taken up by the adhesive on said glass blades must be as small as possible so as not to alter the opta function of the light pipe of the projector.

Thus, advantageously each point of adhesive deposited on said blades has a diameter of between approximately 3 and 5 mm.

According to the example shown in FIGS. 5 and 6, the shorter upper blade 1110 is glued by a point of glue on the intermediate blade 1120, itself glued by two glue points located at each end of said blade, on the longest lower blade 1130.

The glue used to secure said glass slides together is preferably a single-component glue, crosslinkable to ultraviolet radiation, to humidity or to heat. This adhesive is an optical adhesive which withstands temperatures of the order of 250 C applied continuously.

Advantageously, a silicone adhesive of the RTV type from GE or an epoxy adhesive of the NOA71 or NOA65 type from Epotecny is used.

The latter is a single-component resin, 100% crosslinkable to ultraviolet radiation with maximum absorption in the wavelength range from 350 nm to 380 nm. Its crosslinking under ultraviolet radiation takes place in a few seconds depending on the intensity of the radiation and the thickness of the point of glue. Before exposure, this adhesive has a Brookfield cone / plane viscosity at 25 C, at 5 equal to 2.6 20% Pa.s, and a density equal to, 12 g / cm3.

 After hardening, this adhesive has a hardness of 50 to 55 Shores D, an elongation at break of 80%, a tensile strength of 100 to 110 kg / cmZ, modulus of elasticity of 1400 kg / cmZ, a light transmission (in length waves ranging from 400 to 1000 nm) greater than 98%, a refractive index equal to 1.52 and a degradation temperature of between approximately 330 and 350 C.

Then, the reference piece (not shown in FIG. 6) is placed on the superposition of transparent blades 1130, 1120, 11 glued together, so that on the one hand its first horizontal flat part covers the upper surface of the the shortest upper blade 1110, as well as the upper surface the projecting part of the intermediate transparent blade 1120 positioned just below the latter, and on the other hand its second vertical flat part comes against the front faces of the light exit of said transparent blades.

secures the retaining piece to the reference piece using a system 'so that said retaining piece maintains by compression said superimposed transparent blades in abutment against the first and second planar parts of the reference piece, then the mounting plate is removed.

According to a mounting variant not shown which does not include a retaining piece, provision may be made to mount the block of transparent blades glued together on a reference piece comprising a simple lower horizontal return so that the latter is placed against at least part of the lower surface of the lower transparent strip 1130 of the light pipe.

The mounting system of the light pipe of the projector 1000 makes it possible to correctly position the light exit faces of the transparent blades, as well as the oblique reflection facets provided at the end and possibly on the rear face of said transparent blades, with respect to in two reference planes so that said facets cooperate optically with the lenses so that the images of said facets projected by the lenses in the direction of illumination are positioned in a determined manner for the formation of the standardized illumination beam. This positioning in relation to two reference planes makes it possible to overcome deviations due to the manufacturing tolerance of the individual blades. In addition, advantageously, the fact that the Fresnel lenses and the covers are integral with the same mounting piece positioned in a determined manner relative to the reference plate, makes it possible to ensure relative positioning of said lenses and said covers and this whatever dispersion and expansion phenomena that may occur during operation of the lighting module. The lenses and the covers are also well positioned relative to the exit faces of the transparent plates, to said oblique reflection facets. In all cases, the part before mounting makes it possible to maintain the relative positioning of the lenses and the covers, which makes it possible to obtain a clean cut in the light beam.

In addition, the bonding of the transparent blades between them ensures good behavior of the light pipe to shocks and vibrations due to rolling.

The present invention is in no way limited to the embodiments described and shown, but a person skilled in the art will know how to make any variant which conforms to his spirit.

Claims (1)

<U> CLAIMS </U>. Projector (1000) for a motor vehicle, comprising a real light source, means (1001) for concentrating the light radiation coming from this source on the end of a light pipe (1100) constituted by a plurality of juxtaposed transparent blades ( 1110, 1120, 11 in at least one direction, each transparent strip extending along the longitudinal axis (X) of said light pipe and comprising at least at its end furthest from the real light source, an oblique reflection facet ( 1111), said facets constituting as many virtual light sources and being arranged so as to cooperate optically with dioptric elements of axis parallel to the direction of illumination so that they project in this direction, images corresponding to the facets, characterized in that the transparent blades (1110, 1120, 1130) are glued together in point locations, each point of glue present both a diameter of approximately between 3 and 5 mm. 2. Projector (1000) according to claim 1, characterized in that the transparent blades (1110, 1120, 1130) having different lengths, the shorter upper transparent blade (1110) is glued with a point of glue on the lower transparent blade (1120), each intermediate transparent strip (1120) being glued to another strip by two points of glue located at each end of said strip. Projector (1000) according to one of claims 1 or 2, characterized in that the adhesive used is a single-component adhesive crosslinkable to ultraviolet radiation, humidity or heat. Projector (1000) according to claim 3, characterized in that the adhesive is an epoxy adhesive. Projector (1000) according to claim 3, characterized in that the adhesive is a silicone adhesive. 6. Projector ((1000) according to one of claims 1 to 5, characterized in that said transparent blades (1110, 1120, 1130) are made of glass.