JP2006164980A - Lighting module for headlight of automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the effective aperture of a collector by reducing a loss of light flux generated by a bender. <P>SOLUTION: This lighting module for an automobile headlight can generate a light beam having a cutoff, and this module is equipped with a elliptical reflector 1 having a hollow recessed wall 2 located along an optical axis and a light source 5 located near the first focus of the reflector in the recessed part, a convergent lens disposed in the front of the reflector while having a focus F3 located near a second focus F2 of the reflector, a reflective surface having a boundary defined by an end part edge 9 located near the focus F3 of the lens or the cutoff edge between the reflector and the front lens, that is a bender. The front edge of the bender is fixed to the lens L while extending toward the rear part of the lens, and its rear part forms the cutoff edge 8. The reflector 1 has a recessed part facing upward, and is located lower than the bender, as compared with main portions. The light source illuminates the lower part in the recessed part of the reflector. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention is provided along the optical axis,
A reflector, preferably of the elliptical type, comprising at least one light source located in the hollow concave wall and in the recess near the first focus of the reflector;
A focusing lens having a focal point located near the second focal point of the reflector and disposed in front of the reflector;
A reflective surface, i.e. a bender, located between the reflector and the front lens, which is arranged to be at least partially substantially horizontal and said bender is located near the focal point of the lens The present invention relates to a lighting module for a headlight of an automobile capable of generating at least one light beam having a cutoff, which is delimited by an end edge or a cutoff edge.

  An illumination module of this type is known, for example, from EP 1357334, which allows the use of a dip beam or fog type, without the use of a shield that causes a loss of part of the luminous flux of the light source. An illumination beam with a cut-off can be obtained.

  Several embodiments are conceivable with regard to the above-mentioned European Patent No. EP 1357334. In an embodiment comprising an elliptical reflector, preferably with a hollow concave wall, a bender is fixed to the reflector, the front edge of the bender constituting a cut-off edge.

  The positioning of this cut-off edge with respect to the lens must be performed with high precision to prevent chromatic aberration, fuzziness or random cut-off positioning. With such positioning accuracy, it is difficult to design and manufacture means for assembling the reflector and the lens. There is a need to improve such accuracy, especially from the standpoint of maintaining consistency between modules.

  A first object of the present invention is to keep the tolerance of the positioning of the bender relative to the lens economically correct so as to prevent the above chromatic aberrations and defects.

  According to another embodiment shown in FIG. 4 of the above-mentioned European Patent No. EP 1357334, a device for producing an optical system of an illumination module with a single solid optical component made of a transparent material has been devised. Yes. In this case, the reflector is not of the hollow concave wall type, and in order to prevent parasitic refraction, the installation of the light source must be done quite skillfully.

  The outer surface of the elliptical part that acts as a reflector must be provided with a coating of reflective material, which deteriorates. The bender's planar surface must also have a reflective coating. Manufacturing the reflector and lens as a single piece complicates the molding and subsequent application of the reflective coating. The present invention also aims to eliminate such drawbacks.

  It is also desirable to increase the efficiency of the module with respect to the luminous flux. The present invention also aims to reduce the loss of luminous flux caused by the bender and improve the effective aperture of the concentrator. The effective aperture of the concentrator is limited by the angle of the lens aperture.

According to the present invention, an illumination module for an automotive headlight capable of generating at least one light beam having a cutoff of the above type is provided.
The bender is fixed to the lens by its front edge and extends towards the rear of the lens, its rear edge forming a cut-off edge;
The reflector has a concave portion facing upward, and is located below the bender at least with respect to the main portion, and the light source is configured to illuminate substantially downward in the concave portion of the reflector. Features.

  The position of the cut-off edge with respect to the lens is also accurately determined, and a reflective coating can be applied to the inner surface of the concave wall of the reflector.

  The lens can have a top portion that is above the bender and is different from the bottom portion. This top portion can be formed by a convex lens or a biconvex flat lens.

  This top portion is preferably stigmatic (astigmatism) between a point in the air located at the cutoff edge and infinity. Or, if possible, the sharpness of the cut-off facing can be optimized. This top portion can be focused at the center of the cut-off edge.

  In the bottom part, the exit can have a stigmatic surface between a point in the material that merges with the center of the cut-off edge and infinity.

  The base of the top portion of the lens has a wider width at the bender than the base of the bottom portion.

  A transparent material block is fixed to the bottom part of the lens, and this block preferably extends towards the rear. This block, having at least a portion of the horizontal top surface, acts to be totally reflective and constitutes a bender for rays incident on the block. The rear rear surface of the block is preferably vertical and orthogonal to the optical axis.

  One side of this block has a substantially truncated pyramid shape, and the width in the direction orthogonal to the optical axis increases from the rear toward the front.

  As another possibility, a block made of a transparent material can be fixed to the bottom part of the lens, and this block can be extended rearward. The block has a horizontal top surface at least partially, and the top surface is provided with a reflective coating that constitutes the bender.

  The transparent material block or transparent material plate is molded as an integral part of the top and bottom portions of the lens and is preferably manufactured from PMMA (polymethylmethacrylate).

  The illumination module includes a second reflector of an elliptical type, the reflector having a hollow concave wall located on the side of the bender opposite to the first reflector, and the second reflector has the recess defined by the first reflector. And the second reflector comprises a complementary light source located near the first focal point, the second focal point of the second reflector located near the cutoff edge, The light source and this second reflector, when combined with the lens, generate an illumination beam located above the cut-off line, and the combination of these two beams provides the main beam, ie the daytime running beam. Be able to.

  The optical axis of the second reflector is preferably inclined at an angle of about 20 ° from the rear to the front and from the top to the bottom in the plane of the bender.

  The present invention also relates to a headlight including at least one illumination module described above.

  In addition to the above components, the present invention also includes a number of other components. These components will be described in detail in the embodiments described with reference to the accompanying drawings. However, the examples do not limit the present invention.

  The terms “front” and “back” as used in the description and in the claims both refer to the direction of propagation of the light beam. In particular, the adjectives, i.e. the relative positions indicated by the terms top, bottom and horizontal, refer to the module at a position on the vehicle corresponding to the position described in the accompanying drawings.

  1 and 2 show an illumination module E for a vehicle headlight capable of generating at least one light beam having a cutoff. This beam is designed to illuminate below the cutoff line. This cut-off line may be horizontal in the case of fog lights, or may be a line indicated by a broken line having a horizontal branch portion and an inclined ascending branch portion in the case of a dip beam.

  The module E has an elliptical reflector 1 along a horizontal optical axis YY parallel to the longitudinal axis of the vehicle, and the reflector 1 has a hollow concave wall 2 with the recess facing upward.

  The reflector 1 is located on a horizontal plane and is preferably delimited by a curve 3 passing through the optical axis Y-Y. The reflector 1 has a shape that can coincide with the deformed ellipse so as to control the horizontal distribution of the light beam. The reflector is in the form of a cell having an opening 4 facing forward. The reflector 1 includes a first internal focal point F <b> 1 and a second focal point F <b> 2 positioned in front of the planar opening 4.

  The reflector 1 is preferably manufactured from a plastic material with a reflective coating deposited on the inner surface of the wall 2.

  Near the first focal point F 1, a light source 5, which is preferably formed by a light emitting diode, is arranged, which illuminates the lower part in the recess of the reflector 1.

  A converging lens L is disposed in front of the reflector. A means for connecting the lens L to the reflector is provided, but it is not shown. The lens L includes a top portion Lh and a bottom portion Lb, which are different from each other but are connected to each other, and can be made into an integral part by injection molding a transparent material, particularly PMMA.

  The top portion Lh in the embodiment in FIGS. 1 and 2 is a plano-convex lens, and the plane of this lens faces rearward. In a modification, the top portion Lh can be formed by a biconvex lens.

  A bottom portion Lb is fixed to the block 6 made of a transparent material extending toward the rear. This block 6 is an integral part of the parts Lb and Lh. The block 6 has a top horizontal plane 7 which is fixed to the lens L along its front edge. The lens L extends rearward.

  The rear edge 8 is located near the second focal point F2 of the reflector 1, and the focal point F3 of the lens L is also located near or merged with the focal point F2.

  There is a stigmatic portion between the point F3 located in the air at the top portion Lh of the lens and the infinity. This point F3 is located in the middle of the rear edge 8 of the surface 7, and the projection part of the edge 8 constitutes a cutoff.

  The back surface 9 of the block 7 is vertical, and this back surface 9 can be located in a plane perpendicular to the optical axis Y-Y, as shown in FIGS. 1 and 2, in which case the cut-off edge 8 is It is a straight segment.

  As a variant, the edge 8 can be formed by a curved arc coinciding with the curvature of the image plane of the lens. In this case, the back surface 9 is part of a cylindrical surface with a vertical bus, and the directivity curve of this bus corresponds to the edge 8.

  The horizontal plane 7 serves to totally reflect the light beam that has entered the block 6 from the reflector 2, for example, ib1 (FIG. 1). Therefore, this reflection can be obtained without depositing a reflective coating on the surface 7. The efficiency of the luminous flux by total reflection is higher than that obtained by the reflective coating.

  As can be seen from FIG. 2, the block 7 has a width B. That is, it has a dimension in a direction perpendicular to the plane passing through the optical axis, and this dimension increases from the rear to the front.

  The top of the block 7 is substantially truncated pyramid on one side and has a rectangular bottom, with the vertical dimension of this pyramid increasing from the cut-off edge 8 towards the lens. . The bottom portion of the block 6 opposite to the back surface 9 corresponds to the joint portion with the bottom portion Lb. The width of Lb is smaller than the width of the top portion Lh, and the bottom of the top portion protrudes on each side of Lb as zones A1 and A2.

  The exit of the bottom portion Lb is a stigmatic surface 10 between the focal point F4 located in the material of the block 7 and the infinity, which geometrically merges with the center of the rear edge 8. The bottom portion Lb extends downward from the block 6 and is gradually joined to the rear bottom edge of the wall 9 along a surface 11 rising from the front toward the rear.

  The parts Lb and Lh of the block 6 as well as all the parts located below this block are formed as an integral part by molding a transparent material, in particular PMMA, ie optical glass.

  Next, the function of the illumination module will be described with reference to FIG.

  First, the light ray I passing through the focal point F1 of the reflector 2 will be considered. The reflected ray ir passes through the focal point F2 of the reflector 2 that merges with the focal point F3 of the top portion Lh of the lens L. The light beam ie emitted from the lens Lh is parallel to the optical axis YY, that is, the horizontal line in the cutoff line.

  A light ray i2 emitted from a point located in front of the focal point F1 is reflected by the reflector 2 along the light ray ir2. This ray ir2 passes behind the focal point F2, and cuts the focal plane of the lens Lh at the focal point F3. The generated light beam corresponding to the light beam ie2 becomes a light beam that falls below the cutoff line, and does not cause dazzling.

  A light ray i1 generated from a point located behind the focal point F1 is reflected at ir1 and is incident on the back surface 9 of the block 6 below the focal point F3. In the absence of block 6, this ray ir1 should have continued to the back of the top portion Lh of the lens and the resulting ray should have fallen unacceptably.

  Since the block 6 is provided, the ray ir1 is refracted along ib1. Since the refractive index of block 6 is greater than the refractive index of air, ib1 is inclined by a smaller angle with respect to the horizontal line. The light beam ib1 is totally reflected by the surface 6 constituting the bender and falls as the light beam ic1 in the material of the bottom portion Lb.

  The light beam ie1 that exits from the bottom portion Lb also falls below the cutoff edge. Thus, in the absence of a bender formed by surface 7, the unwanted ray ir1 is maintained in the cut-off beam, helping to increase the ray of this beam.

  The improvement of the efficiency of the lighting module according to the present invention is brought about by the following effects.

  The reflection coefficient at the bender 7 due to internal reflection is excellent.

  On the surface 9, the effective angle of the beam generated from the reflector 2 becomes larger than the predetermined lens diameter Lh due to the divergence of the light beam from the reflector 2.

  In one example, a conventional hollow module with similar dimensions provided 63% optical efficiency, whereas the module according to FIGS. 1 and 2 obtained 73% optical efficiency.

  The refractive index of the material of the block 6, that is, PMMA, that is, the optical glass is larger than √2, which is a condition that makes the reflection at the bender 7 total reflection regardless of the incident angle to the surface 9. Regardless of the incident angle of the rays ir, ir1, and ir2 to the bender, reflection at the bender is total reflection.

  FIG. 7 shows a network of iso-illuminance curves (for a constant illuminance) obtained with the illumination module shown in FIGS. 1 and 2 on a screen installed at a predetermined distance from the module, typically 25 m. FIG.

  The horizontal scale gradation defines the orientation of the light ray relative to the optical axis in the horizontal plane, while the vertical scale gradation corresponds to the inclination of the light ray in the vertical line. Maximum illumination corresponds to an internal curve, and a continuous curve with increasing dimensions corresponds to less illumination.

  From FIG. 5, it is clear that the illumination zone is located below the horizontal cutoff line 7 corresponding to the image of the straight edge 8 of the surface 9.

  By providing the bender surface 7 and edge 8 that match the required cut-off line, it is possible to obtain an angled cut-off line with the horizontal part on the left side of the vertical axis and the rising part on the right side. It becomes.

  FIG. 3 shows a variant embodiment in which the various elements of the lighting module of FIGS. 1 and 2 are provided with an elliptical-type second reflector 12 provided with a hollow concave wall above the horizontal plane of the bender 7. .

  The concave portion of the reflector 12 faces upward. At the first bottom focal point F5 of the reflector 12, a second light source 13, preferably a light emitting diode, is disposed to illuminate the top. The second focal point F6 of the reflector 12 merges with the focal point F4 of the bottom portion Lb of the lens and is located in the middle of the rear edge 8.

  The optical axis Y2-Y2 of the reflector 12 is inclined with respect to the horizontal line by an angle α, particularly about 20 degrees, and is separated from the horizontal line from the front to the rear. Therefore, it is possible to leave a space between the reflectors to accommodate the thicknesses of the diode casings and their supporting circuits constituting the light sources 5 and 13.

  The light beam i3 from the focal point F5 is reflected by the reflector 12, becomes ir3, and passes through the focal point F6 obtained by merging the focal point F4 of the lens portion Lb. The exit light is refracted by ib4 and exits from the lens portion Lb as a descending light beam ee4.

  A ray i5 from a point located at the rear of the focal point F5 is reflected along ir5, and this ray passes above the focal point F6 and enters the bender 7. A part of this ray ir5 is reflected by ib5 and enters the back surface of the top portion Lh of the lens. The emission light ie5 rises. The other part of ray ir5 is refracted and impinges on the block merge to merge at ip5, but this ray is lost.

  Accordingly, the emitted light beams ie4 and ee5 from the second light source 13 and the second reflector 12 rise and form complementary beams positioned above the cutoff line. This beam constitutes a part of the main beam, that is, DRL (daytime illumination light).

  FIG. 6 is a graph of an isoillumination curve obtained only from the light source 13 and the second reflector 12. The illumination is substantially above the cutoff line C.

  When the two light sources 5 and 13 are turned on, the main beam, that is, the daytime running beam DRL is obtained by the combination of the beam of FIG. 5 and the beam of FIG.

  It should be noted that the surface 7 in the embodiment of FIG. 3 can be provided with a reflective coating so as to improve the efficiency of the top portion of the light beam from the light source 13 and the reflector 12.

  FIG. 4 shows a modified embodiment, in which a transparent material plate 14 is fixed to the back surface of the lens La, and this plate extends rearward. The plate 14 has a horizontal bottom surface 7a, and at least a part of the bottom surface is provided with a reflective coating obtained, for example, by depositing a metal coating, particularly an aluminum film.

  The plate 14 is molded so as to be an integral part together with the biconvex lens La shown in FIG. The vertical cross section of the plate 14 has a substantially dihedral shape, and the planar top surface is separated from the bottom surface 7a from the rear to the front.

  As can be seen from the above, the plate 14 has a substantially quadrangular contour, which is directed backwards by an edge 8a which forms a linear cut-off edge, as particularly shown in FIG. The boundaries are determined.

  The light source 5 a is positioned so as to be linear with the inclined top surface 15. The second focal point of the reflector 2a is located at the edge 8a.

  The function of the module of FIG. 4 is similar to that described with respect to FIGS. 1 and 2, and is indicated by three rays emitted from the light source 5a. When separating the lens La, all of these rays fall with respect to the optical axis of the lens La or become parallel. The region 16 of connection between the blade 14 and the lens La constitutes a dead zone of a small size that does not participate in the light beam.

  According to the solution of FIG. 4, the thickness of the lens La can be made thinner than in the previous embodiment.

  Whatever the embodiment is conceived, according to the present invention, the accuracy of the bender and the cut-off edges 8 and 8a with respect to the lens can be improved. Optical efficiency is improved and depositing a reflective coating can be omitted or reduced. By adding only the diode 13 and the reflector 12, a complementary beam can be formed above the cutoff (FIG. 3).

1 is a schematic vertical sectional view of an illumination module according to the present invention. 2 is a schematic perspective view of the lighting module according to the present invention rotated about 180 degrees with respect to FIG. FIG. 2 is a schematic vertical sectional view similar to FIG. 1 of an illumination module with a complementary reflector for generating a main beam. 4 is a schematic vertical sectional view of a modified embodiment of the illumination module according to the present invention. FIG. 5 is a network of iso-illuminance curves obtained only by the illumination modules of FIGS. 1, 2 and 4 and the bottom part of FIG. Fig. 4 is a network of iso-illuminance curves located above the cutoff line, obtained only by the top reflector of the embodiment of Fig. 3 and its associated light source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reflector 2 Wall 3 Curve 4 Opening 5 Light source 6 Block 7 Horizontal bottom surface 9 Back surface 12 Reflector 13 Light source 14 Plate 18 Rear edge F1 1st internal focus F2 2nd focus

Claims (15)

Provided along the optical axis,
A reflector (1), preferably of the elliptical type, comprising at least one light source (5) located in the hollow concave wall (2) and in the recess near the first focus (F1) of the reflector;
A focusing lens (L) having a focal point (F3) located near the second focal point (F2) of the reflector and disposed in front of the reflector;
A reflective surface, i.e. a bender, located between the reflector and the front lens, which is arranged to be at least partly substantially horizontal and said bender is near the focal point (F3) of the lens In an automotive headlight lighting module capable of generating at least one light beam having a cutoff, which is bounded by an end edge (8) located at or at a cutoff edge,
The bender (7) is fixed to the lens (L) by its front edge and extends towards the rear of the lens, its rear edge forms a cut-off edge (8);
The reflector (1) has a concave portion facing upward, and is located below the bender at least with respect to the main part,
The illumination module is characterized in that the light source (5) illuminates the lower part substantially in the concave part of the reflector.   The illumination module according to claim 1, characterized in that the lens (L) has a top part (Lh), which is located above the bender and is different from the bottom part (Lb).   A block (6) made of a transparent material is fixed to the bottom portion (Lb) of the lens, the block extends rearward and has a horizontal top surface (7) at least in part, 3. The illumination module according to claim 2, wherein the top surface is totally reflected and constitutes a bender for light incident on the block.   The illumination module according to claim 3, wherein the top portion (Lh) is formed of a convex lens or a double-sided convex lens.   The bottom part (Lb) of the lens has as its exit a stigmatic surface between a point (F4) in the material that merges with the center of the cutoff edge (8) and infinity. Item 5. The illumination module according to any one of Items 2 to 4.   The lighting module according to claim 2, wherein the base of the top portion (Lh) of the lens has a width wider than the width of the bottom portion (Lb) in the bender.   4. A lighting module according to claim 3, characterized in that the rear end face (9) of the block is vertical and perpendicular to the optical axis.   The block (6) has a substantially truncated pyramid shape on one side, and a width (B) in a direction perpendicular to the optical axis increases from the rear toward the front. The illumination module according to claim 3 or 7.   A plate (14) made of a transparent material is fixed to the back surface of the lens (La), and this plate extends rearward and has a horizontal bottom surface (provided with a reflective coating constituting a bender) ( The lighting module according to claim 1, comprising 7a).   The lighting module according to claim 3 or 9, characterized in that the block (6) or the plate (14) is molded as an integral part of the lens (L) (La).   11. Module according to claim 10, characterized in that the block (6) or plate (14) and the lens are manufactured from PMMA.   An ellipsoid type second reflector (12) is provided, which has a hollow concave wall located on the side of the bender (7) opposite the first reflector (1), the second reflector having its recess Toward the first reflector, the second reflector (12) comprises a complementary light source (13) located near the first focus (F5), the second focus (F6) of the second reflector being Located near the cut-off edge (8), the second light source and the second reflector, in combination with a lens, generate an illumination beam located above the cut-off line, of the two beams The illumination module according to claim 1, wherein a main beam, that is, a daytime running beam (DRL) can be obtained by combination. Lumpur.   The optical axis (Y2-Y2) of the second reflector (12) is inclined from the rear to the front and from the top to the bottom on the plane of the bender (7). 12. The illumination module according to 12.   14. Illumination module according to claim 12 or 13, characterized in that the bender (7) has a reflective coating that acts on the light emitted from the second reflector (12).   A headlight comprising at least one illumination module according to claim 1.

Images