FR2806151A1 - REFLECTOR FOR A MOTOR VEHICLE LIGHTING OR SIGNALING DEVICE, AND PROJECTOR OR SIGNAL LIGHT COMPRISING SUCH A REFLECTOR - Google Patents

Abstract

The present invention relates to a reflector (10) for a motor vehicle lighting or signaling device, intended to be associated with a light source (12) to form a light beam of predetermined configuration around a longitudinal optical axis ( Ox), the light source (12) whose largest dimension is arranged along the longitudinal optical axis (Ox), and emitting rays forming with the longitudinal optical axis (Ox) an emission angle (), these rays being reflected by the reflector (10) at an angle of emergence (gamma) with respect to the longitudinal optical axis (Ox), the reflector (10) comprising, on each side of a vertical central plane of symmetry ( xOz) passing through the longitudinal optical axis (Ox), a reflection zone (10d1, 10d2; 10g1, 10g2). According to the present invention, the rays reflected by the reflection zone (10d1, 10d2; 10g1, 10g2), as one moves away from the vertical central plane of symmetry (xOz), pass from a first maximum deviation to a second maximum deviation, the first maximum deviation being divergent and the second maximum deviation being convergent.

Description

A 2806151

  REFLECTOR FOR A LIGHTING DEVICE

  OR MOTOR VEHICLE SIGNALING AND PROJECTOR

  OR SIGNAL LIGHT COMPRISING SUCH A REFLECTOR

  The present invention relates generally to the lighting or signaling of motor vehicles, and more particularly to the reflectors fitted to such devices.

  lighting or signaling devices, as well as headlamps or signaling lights

from such reflectors.

  We already know from documents FR-A-2 609 146 and FR-A-2 609 148 in the name of the Applicant a projector whose reflector comprises two lateral zones of conventional configuration, and for example either parabolic, or of the kind capable of forming by themselves a cut beam of determined shape, and a central zone whose profile in horizontal section is modified compared to said conventional configuration, that is to say deepened or flattened, all

  by connecting essentially without a slope break with the lateral zones. Such a reflec-

  The object is to create by itself, that is to say without the intervention of the glass, a wider beam than with the conventional design, and also to avoid a concentration of light.

  excessive in the center of the glass, which makes it possible in particular to use glass made of plastic

molded tick.

  Document DE-A-197 45 467 also discloses a headlamp for a motor vehicle, provided with a light source and a reflector, in which a screen is arranged, in the light exit path after the reflector, this screen comprising an opening to let light through, the section of this opening being smaller than the section of the reflector. Finally, document FR-A-2 634 003 discloses a reflector comprising, between

  main zones designed to give the beam a certain width, transition zones

  tion. However, such transition zones, or hyperbolas, do not make it possible to avoid, by their own fact or by the very fact of the design of the main zones, zones of

  excessive concentration of light appears at the level of the ice.

  It turned out, however, that all of the reflectors discussed above either offer a re-

  light partition which may lack homogeneity when a very large horizontal spread

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  carrying beam is asked for either cause areas of excessive concentration of

light at ice level.

  In addition, the legislation imposes new relatively restrictive, even contradictory standards, according to which the light intensity, on a screen placed perpendicular to the axis of the projector must on the one hand exceed a minimum value along a line parallel to a horizontal plane passing through the axis of the spotlight and located at 2.5 below this plane, and on the other hand must be less than a maximum value along a line located at 5 in

  below this same horizontal plane.

  The present invention is placed in this context and its aim is to provide a re-

  flector for headlamp or signaling light, large and homogeneous, without the reflector itself being too large, and without light rays

  are lost by component parts of the projector.

  The present invention therefore relates to a reflector for a lighting or lighting device.

  generalization of a motor vehicle, intended to be associated with a light source for

  form a light beam of predetermined configuration around a longitu-

  dinal, the light source the largest dimension of which is arranged along the longitudinal optical axis, and emitting rays forming with the longitudinal optical axis an emission angle, these rays being reflected by the reflector at an angle of emergence from the longitudinal optical axis, the reflector comprising, on each side of a plane of symmetry

  vertical central passing through the longitudinal optical axis, a reflection zone.

  According to the present invention, the rays reflected by the reflection zone, as one moves away from the vertical central plane of symmetry, pass from a first maximum deviation to a second maximum deviation, the first maximum deviation being divergent and the

  second maximum deviation being convergent.

  Preferably, the rays reflected by the reflector pass from the first deflection

  maximum at the second maximum deviation gradually and continuously.

  Advantageously, in an area of reflection, the angle of emergence is a continuously decreasing monotonic function of the angle of emission. we can foresee in this

  case that the continuously decreasing monotonic function is linear.

  According to a preferred embodiment, the reflector comprises, on each side of a horizontal central plane perpendicular to the vertical central plane of symmetry, a surface of which the section by a vertical plane containing a ray reflected by this surface is a parabola , whose

  the fireplace is located near the light source.

  Alternatively, provision may be made for the reflector to have, on each side of a central plane

  horizontal tral perpendicular to the vertical central plane of symmetry, a surface whose section through a vertical plane containing a ray reflected by this surface is a quasi-parabola, the focus of which is located in the vicinity of the light source, in a position which is a function of the angle, relative to the longitudinal optical axis, under which a light ray is emitted

by the light source.

  In all cases, the areas of the reflector situated on either side of the vertical central plane of symmetry have a second order discontinuity, the planes tangent to these areas of

  on either side of the vertical central plane of symmetry forming a non-zero angle and being symmetrical

  relative to the vertical central plane of symmetry.

  A reflector produced in accordance with the present invention will find an advantageous application for forming a headlamp for a motor vehicle, or a signaling light.

for motor vehicle.

  Other objects, characteristics and advantages of the present invention will emerge clearly.

  rement of the description which will now be made of an exemplary embodiment given as

  not limiting with reference to the accompanying drawings in which: - Figure 1 schematically shows a horizontal axial section of a projector provided with a reflector produced in accordance with the present invention; - Figure 2 schematically shows a vertical section of the reflector fitted to the projector of Figure 1; - Figure 3 shows a perspective view of the reflector fitted to the projector of Figure 1 - Figure 4 shows a front view of the reflector of Figure 3; - Figure 5 shows isolux curves of the beam obtained by the right half of the reflector of the projector of Figure 1; FIG. 6 represents isolux curves of the beam obtained by the left half of the reflector of the headlight of FIG. 1, and

  FIG. 7 represents isolux curves of the beam obtained by the whole of the reflective

Figure 1 projector.

  -4- There is shown in Figure 1 a reflector, seen in axial horizontal section, and generally designated by the reference 10. The reflector 10 equips a projector P, which further comprises a light source 12, consisting of the filament d 'a lamp or the arc of a discharge lamp, and a direct light cover 14 disposed in front of the light source 12. The projector P is closed by a glass 16, the edges 18 of which constitute feet of glass , through

  which the ice 16 is held on the cheeks 20.

  The reflector 10 defines a longitudinal optical axis Ox, in the direction of illumination and containing the light source 12, a horizontal transverse axis Oy and a vertical transverse axis Oz. As best seen in Figure 2, the largest dimension of the light source 12 is arranged along the axis Ox. More precisely, the light source 12, shown diagrammatically by a portion of a cylinder, is arranged parallel to the axis Ox

  so that its lower part is tangent to this axis Ox.

  FIG. 1 also shows the vertical projection, in the xOy plane, of the paths of the light rays coming from the light source 12 and reflected by different points of the reflector 10, and in FIG. 2 the horizontal projection of the paths of the light rays

  from the light source 12 and reflected by different points of the reflector 10.

  Figure 2 shows a vertical sectional view of the reflector of Figure 1, without the direct light cover or the closing glass. More precisely, FIG. 2 is a view in vertical section, along a plane parallel to the axis Oz, and containing a ray reflected by the

  reflector 10, and thus forming an angle y with the axis Ox. In Figure 2, O'x 'and O'z' represent

  feel the projections of the axes Ox and Oz in the plane of this Figure, as well as 12 'represented

  feel the projection of the light source 12 in the plane of this Figure, and that the rays

  light from the source 12 and incidents on the reflector 10 are shown in dotted lines.

  It can be seen in FIG. 2 that, in vertical section, the reflector 10 consists of two half-dishes 10H and 10B. The upper half-dish 10H has its focus FH located at the rear of the light source 12, and the lower half-dish 10B has its focus FB located at the front of the

  light source 12. The two half-dishes 10H and 10B have at all points of

  data x, y, z, and in particular in the median plane x'Oy for the points of coordinates x,

  y, 0, a second order continuity in z, i.e. the planes tangent to the surface reflected

  chissant at any point of coordinates x, y, z vary continuously for any variation of the only variable z.

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  We can observe the role played by the different points of the reflecting surface, and in

  particular on both sides of the central axis Ox. In vertical planes x'O'z 'such as de-

  finished above and containing the rays reflected by the reflecting surface, Figure 2 illus-

  in one of these planes, the light rays emitted by the source 12, due to the arrangement of the

  s focal points FH and FB of the two half-parabolas 10H and 10B with respect to the source 12, are all reflected

  chis in a beam of angle a, that is to say a beam whose upper limit is parallel to a horizontal plane, and whose lower limit makes an angle a with a horizontal plane, thus

  as shown in Figure 2.

  The present invention also applies to the case where the half-parabolas 10H and 10B have "piloted" hearths, that is to say that they constitute quasi-parabolas whose

  focus FH and FB occupies a position on the axis Ox which is a function of angle 8, the pro-

  jection on a vertical plane such as that of Figure 2 is represented by 8 ', under which a

  light ray is emitted by the light source 12, relative to the axis Ox.

  We see in Figures 1 and 3 that the reflector has, in horizontal section along the median plane xOy, a second order discontinuity, that is to say that on either side of the xOz plane, the planes tangent to the surface reflecting form a nonzero angle, and moreover they are

  symmetrical with respect to the median plane xOz.

  We can also observe the role played by the different points of the reflected surface.

  chissant, and in particular on both sides of the central axis Ox. In horizontal planes parallel to the xOy plane, as shown in Figure 1, and away from the central axis Ox, the light rays from the light source 12 and very slightly inclined on the axis Ox are reflected by the reflector 10 so as to on the one hand bypass the direct light cover 14 and on the other hand to reach the glass 16, avoiding both the cheeks 20 and the ice feet 18. The rays therefore undergo in this first part of the reflector a deviation

divergent.

  By considering for example only the right half of the projector of Figure 1, we see that the rays emitted by the light source 12, forming an emission angle f3 with the axis Ox, are reflected by the first part 10d1 of the reflector 10 close to the Ox axis by forming

  an emergence angle y with the axis Ox. We see moreover that they undergo a diversion

  gente to the right, and contribute to form the part of the beam located on the right part of

  Figure 5, the maximum deviation being of the order of 40.

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  As the angle 3 of the light rays emitted by the light source 12 increases

  lies with respect to the Ox axis, that is to say as the point of incidence of these rays on the reflector 10 moves away from the Ox axis, the angle with respect to the Ox axis, rays reflected by the part 10d, of the reflector 10 decreases, until vanishing, the reflected light rays then being parallel to the axis Ox, and contribute to form the axial part of the beam, between

+5 and -5.

  By continuing to move away from the Ox axis, that is to say by further increasing the angle of the light rays emitted by the light source 12 relative to the Ox axis, the rays coming from the

  light source 12 and incidents on the second part 10.2 of the reflector 10 give rise to

  sance to rays reflected to the left, whose angle relative to the axis Ox decreases further

  to go from a null value to a negative value. These light rays contribute to form-

  sea the part of the beam located on the left of Figure 5, the maximum deviation being of the order of -20, and initially converging. In addition, the reflected light rays

  by the end of the part 1 Od2 furthest from the light source 12, undergoing a

  converging viation, reach the ice 16 in its useful part, avoiding the ice base 18.

  Because the light source 12 is arranged in such a way that its greatest di-

  mension is arranged along the axis Ox, it follows that the images of this source provided by the part 10d, of the reflector 10 and formed on a screen are vertical or almost vertical, while the images of the source provided by the part 1 0d2 of the reflector 10 and formed on a screen are horizontal or almost horizontal. Sending the quasi-horizontal or horizontal images in the immediate vicinity of the projector axis and simultaneously the images

  quasi-verticals outside the vicinity of the projector axis contributes to satisfying the new

  new regulatory requirements, without having to design a reflector of dimensions

  important, especially in the horizontal direction.

  The beam obtained after reflection on the entire right half of the reflector 10

  consisting of parts 10d, and lOd2 is represented by its isolux curves, as they are il-

glossy in Figure 5.

  The left half of reflector 10, made up of parts 10g and 10g2, gives a confi-

  beam guration symmetrical with respect to the xOz plane, represented by its isolux curves in FIG. 6, and the beam supplied by the whole of the reflector 10 is the sum of the partial beams in FIGS. 5 and 6, and results in its isolux curves as we represented them

in Figure 7.

  It can therefore be seen that the rays are emitted by the light source by forming an emission angle 13 with the longitudinal optical axis Ox and are reflected by the reflector by forming an emergence angle y with the longitudinal optical axis Ox, and that the emergence angle y is a decreasing monotonic function of the emission angle 13. Such a decreasing monotonic function of the emission angle can be linear, of the type: Y = -k, g + k2 okay. and k2 are two positive real numbers, and constitute parameters characterizing the

  shape of the reflector 10 and the boundary conditions, that is to say on the edges of the reflector 10.

  According to the isolux curves desired for the reflector 10 as shown on the Fig.

  gure 7, we can choose any monotonic decreasing function of the emission angle P, and the

  value of the coefficients to obtain any predetermined light configuration.

  Of course, the present invention is not limited to the embodiment which has been described, but it is on the contrary capable of receiving by the person skilled in the art many variants which fall within its scope. Thus, the invention can be implemented in headlamps for passing beams, fog lights, or signaling lights, located at the front or at the rear of the vehicle. In the latter case, we can plan

  that the upper and lower half-parabolas belong to the same parabola of revolution-

  tion, and that the focus of this unique dish is located near the center of the light source. - 8 -

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Claims (10)

  1. Reflector (10) for a lighting or signaling device of a motor vehicle   mobile, intended to be associated with a light source (12) to form a light beam of predetermined configuration around a longitudinal optical axis (Ox), the light source (12) the largest dimension of which is arranged along 1 longitudinal optical axis (Ox), and emitting rays forming with the longitudinal optical axis (Ox) an emission angle (3), these rays being reflected by the reflector (10) at an emergence angle (y ) relative to the longitudinal optical axis (Ox), the reflector (10) comprising, on each side of a plane of   vertical central symmetry (xOz) passing through the longitudinal optical axis (Ox), a zone of re-   bending (1Od1 10ld2; lOgIl, lOg2), characterized in that the rays reflected by the reflection zone   bending (lOd lO d2; lOgI, lOg2), as one moves away from the vertical central plane of symmetry (xOz), pass from a first maximum deviation to a second maximum deviation, the first maximum deviation being divergent and the second maximum deviation being convergent.   2. Reflector according to claim 1, characterized in that the rays reflected by the reflector (10) pass from the first maximum deviation to the second maximum deviation   gradually and continuously.   3. Reflector according to claim 1, characterized in that, in a reflective zone   bending (lOd, lOd2; 1g0, lOg2), the emergence angle (y) is a continuous monotonic function   decreasing emission angle ([3).   4. Reflector according to claim 3, characterized in that the monotonic function   continuously decreasing is linear.   5. Reflector according to claim 1, characterized in that it comprises, on each side of a horizontal central plane (xOy) perpendicular to the vertical central plane of symmetry (xOz), a surface whose section (1OH, 10B) by a vertical plane containing a ray reflected by this surface is a parabola, the focus of which (FH, FB) is located in the vicinity of the light source (12). 6. Reflector according to claim 1, characterized in that it comprises, on each side of a horizontal central plane (xOy) perpendicular to the vertical central plane of symmetry (xOz), a surface whose section (1OH, lOB) by a vertical plane containing a ray reflected by this   surface is a quasi-parabola, the focus (FH, FB) of which is located in the vicinity of the light source   -9- neuse (12), in a position which is a function of the angle (6), relative to the optical axis   longitudinal (Ox), under which a light ray is emitted by the light source (12).   7. Reflector according to one of the preceding claims, characterized in that the zo-   nes (lOdl, l0g,) of the reflector (10) located on either side of the vertical central plane of symmetry (xOz) have a second order discontinuity, the planes tangent to these zones on both sides and   on the other side of the vertical central plane of symmetry (xOz) forming a non-zero angle and being symmetri-   relative to the vertical central plane of symmetry (xOz).   8. Headlamp for motor vehicle, comprising a light source (12), a light   flector (10), a direct light cover (14) and a closing glass (16), characterized in that   that the reflector (10) conforms to any one of the preceding claims.   9. Projector according to claim 8, characterized in that the closing glass (16)   is smooth or slightly deviating.   10. Signaling light for a motor vehicle, comprising a light source   (12), a reflector (10), a direct light cover (14) and a closing glass (16),   characterized in that the reflector (10) conforms to any one of claims 1 to 7,   and in that the closing glass (16) is smooth or slightly deflecting.