FR2688050A1 - PROJECTOR FOR A MOTOR VEHICLE, ESPECIALLY ANTI-FOG PROJECTOR. - Google Patents

Abstract

Projector characterized in that the light element (14) is arranged with its longitudinal axis parallel to the optical axis (12) of the reflector (10), the apex zone (22) of the reflector (10) being produced so that the light emitted by the element (14) is reflected in the form of rays (24) converging in horizontal longitudinal planes, the largest optical image of the element (14) being formed in the lateral marginal zones of a measurement screen placed in front of the projector, and the areas of the reflector (10) located outside the area of the apex (22) reflect the light emitted by the element (14) in the form of rays (34, 40) which converge less strongly in the horizontal longitudinal planes as the distance from the optical axis (12) increases.

Description

Headlamp for motor vehicle, in particular

anti-fog nozzle "

  The present invention relates to a headlight for a motor vehicle, in particular an anti-headlight

  fog, comprising a reflector which generates by reflection light rays emitted by a luminous element

  mineral, a beam of rays dispersed in longitudinal horizontal planes and which are essentially parallel in vertical longitudinal planes. Such a projector is known from document DE-AS-14 97 308.

  This projector has a reflector whose cutting curve through a longitudinal cutting plane

  horizontal axial is a hyperbola while the cutting curves in vertical longitudinal planes are parabolas The reflector is fitted with an element

  luminous whose longitudinal axis is transverse with respect to the optical axis of the reflector The reflector reflects the light rays emitted by the luminous element in the form of a light beam dispersed in a divergent manner in the longitudinal planes homo

  horizontals due to the characteristic of the hyperbola; this beam is formed by parallel rays in the vertical longitudinal planes due to the characteristic of the parabolas Given the fact that

  ble curvature of the hyperbola, the light rays emitted

  by the light source by the reflector, in the di-

  horizontal section, due to predetermined dimensions-

  mined in width and height, includes only one year-

  weak geometric geometry so that this reflector does not use effectively the light emitted by the source

  In addition, this reflector reflects a beam

  luminous skin widely dispersed in hori-

  zontals and which has a vertical extension

  increasing towards the sides The light beam of this known spotlight shines only weakly or not at all

  all marginal areas of the roadway in front of the vehicle

  hicul which complicates the vision of the path and objects existing on the edges of the path for the driver This particularly complicates the driving of the vehicle in fog or

poor visibility.

  The object of the present invention is to remedy

  these drawbacks and to this end concerns a project

  tor corresponding to the type defined above, character-

  in that the light element is arranged so that its longitudinal axis is parallel to the optical axis of the

  reflector, the top area of the reflector being

  aligned so that the light emitted by the light element

  be reflected in the form of light rays

  orchards in horizontal longitudinal planes, the largest optical image of the light element being formed in the lateral marginal zones of a measurement screen placed in front of the projector, and the zones of the reflector situated outside the zone of the apex reflecting the light emitted by the light element in the form of light rays which converge less strongly in the horizontal longitudinal planes at

  measures that the distance from the op axis increases

  tick, these rays generating on the measurement screen smaller optical images of the light element, forming a horizontal light band, and all

  optical images of the light element are placed in-

below a lighting limit.

  The headlight according to the invention offers the advantage that the light emitted by the light element and

  reflected by the reflector, includes a geometrical angle

  important mark which allows to realize inten-

  high light even with a reflector

  small dimensions In addition, the realization of the re-

  flector according to the invention makes it possible to reflect

  intense light optical images of the light element

  dim in the lateral marginal areas of the measurement screen which shows the roadway in front of the vehicle so that the edges of the roadway are strongly lit even in the close-up area which considerably improves the visibility of the road course

  and objects located on the edge of the road.

  According to another advantageous characteristic-

  its of the invention, the marginal zones of the reflector reflect the light emitted by the light element

  in the form of essentially parallel light rays

  them in horizontal longitudinal planes.

  According to another characteristic of the invention

  tion, the marginal areas of the reflector reflect the light emitted by the light element in the form of

  light rays diverging in longitudinal planes

horizontal nals.

  According to another characteristic of the invention

  tion, the top area of the reflector is designed so that as the distance from the optical axis increases, the light emitted by the light element

  is reflected in the form of light rays which

  increasingly deviate in longitudinal planes

horizontal.

  According to another characteristic of the invention

  tion, the convergence of the light rays reflected by the apex of the reflector first increases

  strongly from the optical axis then this increases

  lie less strongly or even remain constant.

  According to another characteristic of the invention

  tion, all the optical images of the light element touch the limit of illumination (limit between the

bright area and shaded area).

  According to another characteristic of the invention

  tion, the illumination limit is horizontal.

  The present invention will be described below using two embodiments shown diagrammatically in the drawings in which:

  Figure 1 is a horizontal central section

  zontale of a projector corresponding to a first

example of realization.

  Figure 2 is a vertical central section

wedge of the projector of figure 1.

  Figure 3 shows the optical images

  of a light element reflected on a measurement screen

  re by the projector according to Figures 1 and 2.

  Figure 4 is a horizontal central section

  zontal of a second example of realization of a pro-

jector.

  Figures 1 and 2 show a first example

  full of a projector The projector includes

  takes a reflector 10 made of metal or plastic material

  that placed in a box not shown The reflec-

  tor 10 is in the form of a curved hollow body and on its optical axis 12 there is the illuminating element 14 of a light source 16 The light source 16 can be

  an incandescent lamp and in this case the element lu-

  mineux 14 is the filament of the bulb; he can also

  LEMENT be a discharge gas lamp and in this

  case the light element 14 is its electric arc The

  the light element 14 is arranged so that its long axis

  tudinal is substantially parallel to the optical axis 12 The light exit orifice 18 of the reflector 10 can be covered with an optic 20 in the form of transparent glass without element having an optical effect

  or as a dispersion disc with pre-

  feeling an optical effect to influence the beams

  light reflected by the reflector 12.

  At its apex 22, the reflector 12 is made so that the images of the light element 14 are reflected to form a beam of rays

  essentially parallel in a horizontal plane

  longitudinal zontal as shown in figure

  gure 1, converging and in a longitudinal plane

  vertical as in figure 2 In the longitudinal plane

  vertical, the rays of the light beam are

  substantially parallel and the whole is horizontal or the direction 26 of the light is slightly

  tilted downwards The convergence of the light rays

  neux 24 increases strongly from the optical axis 12 so that the light rays 24 are increasingly

  more inclined with respect to the optical axis 12 in function

  tion of the remoteness of this reflecting part

  of the reflector with respect to the optical axis 12 at a cross

  sant this optical axis and lighting as shown by the measurement screen shown in Figure 3, in its

  lateral marginal zone The light rays 24 reflected

  chis by the part of the reflector located to the right of the optical axis 12, Figure 1, thus illuminate the screen of

  measurement to the left of the optical axis 12 and vice versa.

  The apex area 22 reflects large images 28 of

  the light element 14 because of its proximity to

  port to the light element 14 according to Figure 3; these

  images have their upper edge placed along a line

  horizontal lighting mite 30 (limit between the light area and the dark area) 28 reflected images

  by the central part of zone 22 of the summit, at the

  calf of the optical axis 12 for the light element 14, are located near the middle of the measurement screen but the images 28 which are reflected by the parts

  from the summit zone 22 located at a certain distance

  ce of the optical axis 12 are located in the mar-

  side of the measurement screen due to the

  1 O very rapidly increasing convergence of light rays

  neux Figure 3 represents only some images

  optics 28 given by way of example.

  In the central zones 32, which are already

  laterally to zone 22 of the summit, the reflec-

  tor 10 is made so that the light rays 34 are reflected in a less convergent manner in the horizontal longitudinal planes as the distance from the optical axis 12 increases, like these light rays 24 from the area from the top 22, in the vertical longitudinal planes, are essentially parallel and horizontal or are slightly inclined downwards in the direction 26 of the light The inclination of the light rays 34 thus increases with respect to the optical axis 12 as increases the distance of this reflector part from the optical axis 12 The optical images 36

  of the light element 14, reflected at a crossed distance

  health compared to central area 32 and of which

  only one is shown by way of example

  ple in Figure 3, thus move from the edge of the

  measurement screen towards its middle and decreasing more and more The optical images 36 reflected by the central zone 32 form on the measurement screen a horizontal light band extending between the marginal zones and the middle of the measurement screen and this

  below the lighting limit 30.

  The lateral marginal zones 38 of the reflective

  10 are made to reflect the rays

  luminous 40 at a time in longitudinal planes ho-

  horizontally and vertically, in a substantially parallel manner Therefore, the marginal zone 38 does not reflect any optical image 42 of the light element 14 at

middle of the measurement screen.

  These images 42 can be used to carry out

  1 o a strong lighting intensity below the limit

  lighting 30 at the optical axis 12,

  i.e. in the central area of the measurement screen

  re. Each reflector zone which reflects the optical images 28, 36, 42 can be crossed by a cutting plane passing through the optical axis 26 Depending on the position of the respective reflecting zone, the plane

  of corresponding cut has a certain inclination

  sound with respect to a horizontal of the median plane.

  The inclination of the section planes through a reflector zone located in the horizontal median plane is

  nothing; this means that it is the median plane itself

  even For a reflector area located in a plane

  vertical median, the inclination of the cutting plane cor-

  respondent is at 9 Q O with respect to the median hori-

  zontal The inclination of the optical images 28, 36, 42, reflected by each reflector zone with respect to a horizontal plane on the measurement screen corresponds to the inclination of the respective cutting plane relative to

  in the horizontal median plane Thus, the reflective zones

  in the horizontal median plane are re-

  flexed as horizontal optical images of

  the light element 14 and the reflector zones if

  killed in the vertical central plane reflect vertical optical images Between these two extreme positions, there are all the intermediate positions for the optical images of the light element 14, that is to say inclinations between OO and The passage between the zone 22 of the top, the central zone 32 and the marginal zone 38 of the reflector is continuous, that is to say without rupture and without crease

  which allows simple manufacture of the reflector 10.

  In addition, this avoids any disturbance of the beam of rays reflected by the reflector 10 and which would

  caused by irregularities in the shape of the reflec-

  tor The reflector 10 described above receives both vertically and horizontally the light emitted

  by the light element 14 in a space angle im-

  bearing to use it for the show The realization-

  tion described above of the reflector 10 is advantageous

  especially when used as an anti-beacon

  fog for a motor vehicle In this case, the large images 28 of the light element 14, reflected by the apex zone 22 form a light strip of significant vertical amplitude but

  of relatively low light intensity The ima-

  smaller ages 36 of the light element 14, reflected

  chies by the median zone 32 form a strip of

  horizontal area located directly below the lighting limit 30; this strip has a small vertical extension relative to the light strip reflected by the apex area 22 The apex area 22 does not reflect any image 42 of the light element 14 in the middle area of the measurement screen and which

  thus allows a significant light intensity di-

  directly below the lighting limit Tou-

  the optical images 28, 36, 42 of the light element

  neux 14 illuminate the measurement screen in an area

  limited in the upper part by the lighting limit 30 and which has in the lower part a limit line 31 in the shape of an inverted U This lower limit line 31 results from the fact that the vertical extension of the optical images of the light element 14, reflected by the lateral marginal zones of zone 22 on the measurement screen is greater than that of the optical images

  of the light element 14 reflected by the media area-

ne 32 and the marginal zone 38.

  The measurement screen represents the roadway if-

  1 O killed in front of the vehicle and thus lit by

  the beam of light rays emitted by the projector.

  The lighting described above of the measurement screen can

  thus transpose to the illumination of the roadway.

  The edges of the road are also lit in

  the close area because of the strong green extension

  optical images 28 of the lighting element

  ment 14 when the middle of the roadway is not lit or is only dimly lit

  edges of the roadway in the nearby area, the

  conductor can easily see these areas, which is particularly advantageous in foggy weather or,

  in general, when visibility is poor.

  Illumination even in the middle of the road, in the

  close range, would not improve the vision of the

driver of the vehicle.

  In the second example embodiment shown

  felt in FIG. 4, the region of the apex 122 and the central region 132 of the reflector 10 have the same shape as

  in the first example of implementation The margi-

  nale 138 of the reflector 110 is made to continuously reflect the light rays 140 divergently in the horizontal longitudinal planes and to reflect them so that they substantially meet

  parallel in the vertical longitudinal planes.

  This embodiment of the reflector 110 makes it possible to arrive with respect to the first example of embodiment at a

  homogeneous and particularly intense lighting at

  calf of the optical axis 12 The transition between the area

  vertex 122, the middle zone 132 and the margina-

  the 138 is continuous in the reflector 110 as in the first embodiment In the embodiment of the reflectors 10 or 110, first of all a certain light distribution is chosen on the measurement screen for the light beam which must be reflected by reflector 10, 110 The distribution of fixed light thus in the different areas of the screen

  measures the necessary light intensities These in-

  light densities are determined by the optical images of the light element 14, reflected on the respective areas of the measurement screen From the optical images of the light element 14, necessary to obtain the predetermined light intensities in the different areas of the measurement screen, we can determine, according to the laws of reflection, the

  shape required for the reflector At the start of the cal-

  bottom of the shape of the reflector we predetermine the

  tance of the top 44 of the reflector 10, 110 on the op axis

  tick in relation to the light element 14 Starting from the top, the shape of the reflector is calculated step by step

  determining for each zone of the reflector 10, from

  shooting of the position of the optical image of the lu- element

  miners 14 that this area should reflect, using

  the geometric laws of reflection, the angle of inci-

  dence of the light ray emitted by this light element 14 with respect to the normal 46 to the area concerned

  reflector and making this angle equal to the angle reflected-

  chi, we determine the direction of the normal 46 for this zone of the reflector From the direction of

  normal 46, we determine perpendicular to this

  this one, the plane tangent 48 to the concerned point of re-

1 i

  bending and thus the alignment is determined La juxta-

  position of the reflector points thus obtained gives

  the continuous shape of the reflector, without steps or folds.

Claims (1)

R E V E N D I C A T I O N S   1) Headlamp for motor vehicle, no-   tally fog light, comprising a reflective   tor (10, 110) which generates by reflection light rays   mineral emitted by a light element (14), a beam   rays scattered in horizontal planes longi-   which are essentially parallel in   vertical longitudinal planes, character projector   in that the light element (14) is arranged so that its longitudinal axis is parallel to the axis   optic (12) of the reflector (10, 110), the area of   puts (22, 122) of the reflector (10, 110) being produced so that the light emitted by the light element (14)   either reflected in the form of light rays (24)   orchards in horizontal longitudinal planes, the largest optical image (28) of the light element (14) being formed in the lateral marginal zones of a measurement screen placed in front of the projector, and the zones (32, 38, 132 , 138) of the reflector (10, 110) located outside the region of the apex (22, 122) reflecting the light emitted by the light element (14) in the form of light rays (34, 40, 140) which   converge less strongly in the longitudinal planes   horizontal as the distance from the optical axis (12) increases, these rays generating on the measurement screen smaller optical images (36, 42) of the light element (14), forming a horizontal light strip, and all the optical images (28, 36, 42) of the light element (14) are placed   below a lighting limit (30).   ) Projector according to claim 1, ca-   characterized in that the marginal zones (38) of the re-   reflector (10) reflect the light emitted by the   light element (14) in the form of light rays   (40) essentially parallel in long planes horizontal tudinals.   ) Projector according to claim 1, ca-   characterized in that the marginal zones (138) of the re-   reflector (110) reflect the light emitted by the   light element (14) in the form of light rays   (140) diverging in horizontal longitudinal planes rate.   ) Projector according to claim 1, ca-   characterized in that the vertex zone (22, 122) of the re-   flector (10, 110) is designed so that as   lies the distance from the optical axis (12), the   light emitted by the light element (14) is reflected   shit in the form of converging light rays (24)   more and more in horizontal longitudinal planes rate.   ) Projector according to claim 4, ca-   characterized in that the convergence of light rays   (24) reflected by the vertex area (22, 122) of the re   flector (10, 110) first increases strongly starting from the optical axis (12) then this increases less strongly or even remains constant.   6) Projector according to the claims pre-   cédentes taken as a whole, characterized in that   that all the optical images (28, 36, 42) of the element   luminous (14) touch the limit of illumination   (30) (limit between the light area and the shadow area).   ) Projector according to one of the claims   previous actions, characterized in that the limit   of illumination (30) is horizontal.