FR2558237A1 - Indicator light for motor vehicle. - Google Patents

Abstract

Indicator light for motor vehicle whose lighting surface 3 has a width distinctly greater than its height, this light comprising a casing 1 in which a bush 7 is mounted for a light bulb 9 whose optical centre is situated on the general optical axis Y-Y of the optical system of the light, and reflecting means 19 for deflecting the divergent light beam from the light bulb 9 towards the said lighting surface 3, this light being characterised in that it comprises at least one dioptric interposed between the said light bulb 9 and the said reflecting means 19 in order to convert the said divergent light beam into a parallel beam directed laterally in the said casing 1 along a secondary axis X-X which is perpendicular to the general optical axis Y-Y of the system and in that the said reflecting means 19 are oriented in at least one plane which is oblique with respect to this axis in order to reflect the said parallel beam onto the lighting surface of the light with a uniformly distributed intensity.

Description

 The present invention relates to signaling lights for a motor vehicle. More particularly, the invention relates to the rear lamps of motor vehicles whose width is much greater than the height.

 The active (visible) surface of a motor vehicle career lamp must have, during its operation, a luminance as constant as possible over the entire illuminating surface.

 It is usual to associate with a bulb whose filament is theoretically a luminous point, a parabolic reflector and an ice whose shapes correct the luminance distribution at best. Circular ice is therefore best suited for this purpose.

 On the other hand. on current vehicles, the lights are rectangular. Constant luminance can be obtained by parabolic or semi-parabolic reflectors, and those skilled in the art by other tricks customary to the art can produce an acceptable fire.

 The evolution of the style of the vehicles leads to consider that the fire is part of the overall aesthetics of the car and the appearance of the ice evolves into functional bands, colorful or not, much wider than high.

 The current means of fire design are no longer able to ensure regular luminance from a point filament.

 We have already developed fire of the indicated type in which the distribution of luminance over the width of the fire is ensured by the use of several bulbs arranged along this width at regular distances It is obvious that this solution is unsatisfactory because it leads to energy consumption and a short student.

 The object of the invention is therefore to provide a vehicle signaling light whose width is much greater than the height, which has a distribution of uniform luminance over its entire width with a reasonable energy consumption and cost.

 The invention therefore relates to a signaling light for a motor vehicle whose illuminating surface has a width substantially greater than its height, the light comprising a housing in which is mounted a socket for an ampoule whose optical center is located on the general optical axis of the optical fire system, and reflective means for deflecting the divergent light beam from the bulb towards said illuminating surface. this light being characterized in that it comprises at least one dioptric block interposed between said bulb and said reflector means for transforming said divergent light beam into a parallel beam directed laterally in said casing along a secondary axis which is perpendicular to the axis general optical system and in that said reflector means are oriented in at least one plane which is oblique with respect to this axis to return said parallel beam on the illuminating surface of the fire with an evenly distributed intensity.

 trace to these characteristics, by means of the use of a single bulb of conventional shape, the illuminating surface of the fire appears with a luminance substantially equal over its entire width.

The invention will be better understood with the aid of the description which follows, given solely by way of example and with reference to the accompanying drawings, in which - FIG. i is a horizontal sectional view of a first embodiment of a signaling light according to the invention;
- Fig.2 is a front view of the fire with partial tearing;
- Fig.3 is a partial view in perspective and on a larger scale;
- Figure 4 shows a view, partially in axial vertical section, a dioptric block used in the traffic light;
FIG. 5 is a diagram illustrating the optical configuration of the dioptric block;
Fig. 6 is a partial schematic view of the traffic light showing a preferred embodiment of a translucent ice-exit glass;
FIG. 7 represents on an enlarged scale the portion of the ice surrounded by the circle A in FIG. 6;
FIG. 8 schematically represents a variant of the output ice:
- Fig.9 is a horizontal sectional view of another embodiment of the signaling light according to the invention;
- Fig.10 is a front view, the output ice being removed;
Fig.11 is a cross-sectional view of the fire;
- Fig.12 is a sectional view similar to that of Fig.11 while the bulb and the dioptric block are removed;
- Fig.13 is a diagram illustrating the optical configuration of the dioptric blocks used in the traffic light of Fig.9 to 12;
- Fig.14 is a perspective view of this dioptric block.

Referring to FIGS. 1 to 4, the general construction of the first embodiment of the lamp according to the invention will firstly be described. This example relates to a rear light of a motor vehicle which is supposed to be placed in such a way that the great dimension of the illuminating surface is oriented horizontally. Of course, this position is chosen only for the convenience of the explanation, because the fire can be implanted in the vehicle in any other desired position depending on the shape of the body, aesthetics, requirements, regulations and other similar factors,
The traffic light comprises a housing 1 closed by a composite glass 2 which constitutes the vertical illuminating surface 3 having a width l significantly greater than its height h.

 The bottom of the housing comprises a central portion 4 extending substantially parallel to the illuminating surface 3 and two symmetrical and inclined portions 5 and 6 extending from the corresponding edges of this central portion to the illuminating surface.

 In the central part 4 has come to form a mounting sleeve 7 of a lamp socket 8 in which is inserted a bulb 9. This is of a usual bayonet type, the socket 8 being fixed to the housing 1 by elastic snap hooks 10 provided on the mounting sleeve 7. Any other form of mounting of the bulb may be provided.

The bushing 8 and the bulb 9 which are coaxial define an axis YY which is the main axis of the optical lighting system of the fire. (See in particular
Fig.3) and which is here oriented horizontally. It will be no-tera that the filament 11 of the bulb is disposed along a vertical axis ZZ perpendicular to the axis YY.

 In each longitudinal wall of the housing 1 are provided two U-shaped cutouts 12 each delimiting a resilient fixing tongue 13 provided with an opening 14 of rectangular shape, being extended that corresponding openings in the opposite walls of the housing 1 are aligned with certain precision.

 In each pair of opposite openings 14 is inserted a radial mounting lug 15 of a dioptric block 16 which has a generally cylindrical shape (see in particular Fig.4). The mounting lugs 15 are provided with a rounded edge 17 (FIG. 3) facilitating the insertion by elastic engagement of each dioptric block into the box, however after mounting the exact positioning is ensured by the elastic tongues 13.

 With this arrangement, the dioptric blocks 16 are accurately aligned on a secondary optical axis X-X which passes through the center of the filament 11 and the intersection of the Y-Y and Z-Z axes to which it is perpendicular.

 Note that the entire fire is preferably made of a plastic material, but that against the dioptric blocks 16 are preferably made of glass.

 Each dioptric block 16 is intended to transform the quasi-spherical light beam from the bulb 9 into a parallel beam directed along the X-X axis, that is to say parallel to the illuminating surface 3 of the light.

 The radii of these lateral beams are respectively directed on two inclined planes 18 coated with reflective surfaces 19 which extend longitudinally in the housing 1 to deflect the respective lateral beams towards the composite ice 2.

 As can be seen in FIGS. 1 and 6, each reflecting surface comprises a curved portion 20 located near the bulb and a flat portion 21 which extends to the end of the housing and which mainly captures the beam lateral parallel from the corresponding dioptric block 16. The flat portions are inclined on the axis XX and thus return the parallel beams to the ice 2 (see also Fig.6).

 In the present embodiment, the glaze 2 is composite and comprises a translucent non-colored plate 22 suitably fixed on the case 2 (by gluing, for example), and an overmoulding 23 colored according to the optical signal to be delivered by the fire. . The plate 22 has a serrated profile on a portion of its inner surface thereby optically constituting a network of prisms 24 parallel to each other and extending in the direction of the height h of the fe-u. This network is intended to give the light emanating from the fire, a suitable configuration adapted to its function. This light can be parallel or diffuse or even concentrated to a certain extent. The color of the fire can also be obtained by tinting the dioptric blocks 16 whereby the ice 2 does not need overmolding but may be colorless.

 The case represented by way of example in FIGS. 6 and 7 makes it possible to confer on the luminous flux a parallel configuration.

Considering only one half (the right half in this case) of the plate 22, the latter being symmetrical on both sides of the median vertical plane YZ of the eu, it can be noted that each prism has a face input fe (Fig.?) extending
parallel to this plane and an oblique face fo
inclined on this year of a certain angle a (Fig.6). The
considered prism network has a first group
25a in which the angle has changed from a minimum value to a maximum value, and a second group 25b in which this angle is constant.The transition between these two groups of risers 25a, 25b is localized on the plate 22 as a function of rays of light that strike the latter.

 The bulb 9, which is approximated as being a point source, irradiates the central portion 5 of the plate 22 on the inner surface of which are provided bosses 26 intended to ensure the diffusion of the light that strikes this part directly. from the filament 11.

 Each part 25a of the plate 23 receives a divergent light beam coming from the concave portion 20 of the reflector 19, this concave portion receiving a part of the parallel beam coming from the dioptric block 16.

 Each tartie 25b obliquely receives a beam parallel to the flat portion 21 of the reflector 19, this parallel beam being derived from the dioptric block 16. The beams of the diverging light beam returned to the plate 22 by the concave portion of the reflector strike the faces input of prisms 24 d group 25a at angles which are specific to each ray. To obtain an aligned beam emanating from the illuminating surface 3 (what is sought here), the oblique faces fo of the prisms of the group 25a make progressively increasing angles of the portion 25c of the plate outwards to the first prism which receives a radius of the flat portion 21 of the reflective surface 19. The transition between the two groups of prisms has been indicated by the line t in Fig.7.

In other words, a dimension of this transition line t (here on the left) the angle an is greater than
below the angle a 1 and the angle an 1 is greater than 1 angle year 2 'To the right of the transition line t the value of the angle a is constant for all
x - prisms.

 Of course, since the plate 22 is symmetrical with respect to the Y-Z plane, the arrangement of the plate on the opposite side to that shown in FIG. 6 is the mirror image of this Figure.

 The particular shape of the plate 22 that has just been described makes it possible to obtain a quasi-constant density of the luminous flux coming from the lamp according to the invention, despite the very large width thereof relative to the dimension of the source. constituted by the bulb 9.

In the example described so far with reference to FIGS. 6 and 7, the rays striking the input faces fe of the prisms 24 are deflected at refraction angles r 'and returned parallel to the input faces fe by total reflection. on oblique faces fo, thanks to the judicious choice of angles to prisms.
If it is desired to obtain a diffuse luminous flux over the entire width of the fire, it is advantageous to use the prism shape represented on the
Fig.8. In this case, each prism 24a has an input face fe plane as for the prisms 24, while their refraction face fr is convex to these planar faces. It is understood that in this way each ray is deflected at a different angle so that globally, the flow of the illuminating surface is diffuse.

 We will now return to Fig.1 to 4 while referring to Fig.5 to describe each of the dioptric blocks IS used in the traffic light according to the invention.

 Each dioptric block 16 has a generally cylindrical and partly tubular shape and is preferably made from a single molded glass body.

 The central part of the block is constituted by a convergent meniscus 27 whose input diopter is of spherical shape centered on the point O (FIG. 5) which materializes the light source considered as point in the present description. The exit diopter ds of this meniscus is convex, its focus being located in point 0.

 The converging meniscus 27 is surrounded by an annular thick lens 28 having as an input diopter the surface of and as an exit surface a diverging exit diopter whose focus is a point 0 ', image of the point O on the YY axis with respect to a point of this axis which corresponds to the radius of the dioptric block cylindrical. The points O and O 'are therefore separated by a value equal to the height of the box 1.

The thick lens 28 comprises another active surface dr which is a total reflection surface optionally metallized by a layer of paint 29 (FIGS. 3 and 4), or any other similar means.

 The diopter of is connected to the total reflection surface by a bevelled surface 30 which has no particular optical role.

 The dioptric block 16 transforms the spherical beam of the source into a parallel beam of substantially uniform density and oriented along the secondary axis X-X of the optical system.

dans laquelle :
x et y - coordonnées d'un point quelconque des courbes,
n - indice de réfraction du matériau du bloc dioptrique,
C - constante.In a coordinate system, established in a radial plane of the dioptric block 16 I for example the plane XY), it is shown that the curves of the output diopters ds and ds. are governed by the following equation:

in which :
x and y - coordinates of any point of the curves,
n - refractive index of the material of the dioptric block,
C - constant.

 In order to determine the curves ds and ds ', the aforementioned coordinate system and an auxiliary system x', o ', y' whose axes of the ordinates are merged and whose axes of the abscissae are offset by a distance 2a respectively, are admitted respectively. ê being the radius of the cylindrical body of the optical block 16.

 We determine the coordinates of a point A which is the point of connection of the two curves respectively in the two coordinate systems, ie in the system x. o, y, A = (X, Y) and in the system x'o'y ', A = (X' Y ') with x' = x and y '= 2a-Y.

Note that the coordinates of point A correspond to the equation
1 Y = ------------ X t 2a
tg (sini arc / n) in the first coordinate system and to
Y = 1 tg (arc sin1 / n) in the second.

By determining the value of the constant C in the first system, we find {x = X and y = Y).

pour la courbe du dioptre ds'.

by putting this value in the general equation of the curve, we find

for the diopter curve ds'.

 It should be noted that both formulas correspond to elliptic curves.

 A second embodiment of the invention will now be described with reference to Figs. 9-14.

 The fire represented in these figures comprises a housing 31 of elongated and narrow shape whose bottom is stepped on either side of the central portion in which is placed a bulb 32 with its socket 33. The housing is closed by an ice 34 which can be composite, as in the previously described fire, diffusing means and light coloring that can be provided. Ice 34 defines the illuminating surface 35 of the fire.

The fire also comprises two dioptric blocks 36 placed respectively on either side of the bulb 32 and fixed by a flange 37 and hooks 38 in the sleeve 33 (see especially the
Fig.14), or any other similar fastening means.

 Each dioptric block 36 is approximately in the form of a cap whose outer surface 38 is generated approximately by rotation of an elliptical curve about the X-X axis.

 Fiv.13 schematically shows the shape of each dioptric block 36.

Because of the important angle at which the light rays of the source strike this dioptric block, it is desirable for the outer surface 38 thereof to be defined by two elliptical curve portions going respectively from the point R situated on one axis XX ( here we consider an axial plane
XY of the dioptric block) to a point S and from this point S to a point T beyond which the luminous flux of the bulb 32 strikes the ice 34 directly.

 Between the point R and the point S, the curve of the surface 38 is governed by the same equation as that which defines the curves ds and ds of the previous embodiment. Beyond the point S, the curve is more flattened to ensure the parallelism of the output rays, despite the significant angle of incidence of rays striking it. In Fig.13, there is shown the extension of the section RS by a dashed line.

 The inner surface of the dioptric block 36 is formed of a series of facets 39a to 39k whose profile is determined according to the profile of the outer surface 38. Thus, the facets 39a to 39d have a spherical profile centered on the point 0, each facet having a distinct radius. From the point S, the facets 39e to 39k are determined so as to transform the opening angle 11 of two adjacent rays from the point O into an opening angle, which is less than half that in order to increase the angle of interception of the light flux from the source.

 Further flattening the curve of the outer surface 38 on the stub ST and adapting the profile of the facets of the inner surface has the advantage of being able to recover the portion of the luminous flux radiated by the source in the angle O which would be lost if the curve RS was extended to the point T which would be the extreme point beyond which the parallelism of the output radii could no longer be obtained. The particular shape of the dioptric block 36 thus makes it possible to make maximum use of the light flux of the source in order to distribute it laterally with a uniform density.

 The bottom of the housing 31 is staggered on either side of its vertical plane of symmetry YZ, each corresponding part 40 of this bottom therefore comprises rungs 41a to 41f whose distance to the outlet ice 34 decreases from the center to the ends The echelons are flat and have no optical function proper. They are connected to each other by reflective facets 42a to 42e of the profile which is convex towards the center of the fire. In addition, each facet (Fig.1Z) has two surfaces marked sa and sb respectively inclined on the X-Y plane of the fire and symmetrical with respect to this plane. These inclinations are reversed with respect to facets 42a and 42b with respect to facets 42d and 42e.

The ray paths are indicated on the
Fig.9. It can be seen that each facet 42a-42e receives a parallel-ray light sheet of the corresponding dioptric block 36 and returns this sheet to the outlet ice 34 by spreading it over a certain angle.

The curvature of the facets is chosen such that the luminous fluxes from the different facets create adjacent and contiguous illuminated areas on the ice 34.

 As well as the fire which corresponds to the first embodiment, that represented in FIGS. 9 to 14 thus makes it possible to create on the illuminating surface 35 a luminous flux of uniform density despite the very elongated shape of the case 31.

 Note that we can design a traffic light limited to one half of the lights shown here, the bulb is then placed near one end of the housing.

Claims (19)

 1. Signaling lamp for a motor vehicle whose illuminating surface (3; 34) has a width (1) clearly greater than its height <h), the lamp comprising a housing (1:31) in which a socket (7) is mounted 33) for an ampoule (9; 323 whose optical center is situated on the general optical axis (YY) of the optical system of the lamp, and reflector means 119; 40) for deflecting the divergent light beam of the bulb ( 9; 32) towards said illuminating surface (3; 34), said light being characterized in that it comprises at least one dioptric block (16; 36) interposed between said bulb (9; 32) and said reflector means [19; 40) for transforming said divergent light beam into a parallel beam laterally directed in said housing 11; 31) along a secondary axis (XX) which is perpendicular to the general optical axis (YY) of the system and in that said means reflectors (19; 40) are oriented in at least one plane which is obl ort to this axis to return said beam parallel to the illuminating surface of the fire with an evenly distributed intensity.  2. Signaling light according to claim 1, characterized in that said bulb (9; 32) is placed in the center of said housing (1:31) and in that said general optical axis (YY) is situated in the plane of symmetry cross section of the housing (1; 31), the bulb irradiating reflector means (19; 40) located on either side of this plane of symmetry.  3. Signaling light according to any one of revendicazions 1 and 2, characterized in that said reflector means 119) are of generally planar shape and said dioptric block (16) comprises a body of generally cylindrical shape whose axis coincides with said secondary axis (XX) and which comprises a central convergent meniscus 127) and a tubular-shaped thick lens (28) partially surrounding the converging meniscus and extending from the meniscus (27) along the axis (XX) of the side of the meniscus opposite said bulb <9), said thick lens having an output diopter diverge (ds') to capture the rays of the bulb (9) passing through the dioptric block (16) and reflected on the outer surface of this one.  4. Signaling light according to claim 3, characterized in that said meniscus (273 and said thick lens (28) comprise a common input diopter (of) of spherical shape and centered on the optical center of said bulb (9). .  5. Signaling light according to any one of claims 3 and 4, characterized in that the cylindrical outer surface of said dioptric block (1S) is coated with a metallization layer for improving the reflection.  6. Signaling light according to any one of claims 3 to 5, characterized in that the output diopter (ds) has an elliptical profile whose focus is located on said optical center (0).  7. Signaling light according to any one of claims 3 to 6, characterized in that the radius of said dioptric block (16) being a, the exit dioptre (ds') of said thick lens has an elliptical profile whose focus is located on the main axis (YY) of the optical system at a distance (2a) from said optical center (0)  8. Signaling light according to any one of claims 3 to 7, characterized in that said reflector means (19) comprise a diverging portion (20) in the vicinity of said dioptric block (16).  9. Signaling light according to any one of claims 1 to 8, wherein said illuminating surface (3; 35) is housed on an ice (2:34) closing said housing (1; 31) characterized in that said ice is composite and comprises a light distribution layer (22), and optionally a coloring layer (23) giving the fire the required function.  10. Signaling light according to claims 8 and 9, taken together characterized in that the light distribution layer t22) comprises an array of prisms (24; 24a) for receiving light reflected by said reflector means (19) and an array of dispersing elements (26) for receiving light directly from said bulb (9).  11. Signaling light according to claim 10, characterized in that each prism t24) extends from one longitudinal edge to the other of said distribution layer (22).  12. Signaling light according to claim 11, characterized in that said prism array t24) is divided into a first zone (25a) for returning light from the curved portion (20) of said reflector means (19), an area in which the angle of deflection of the light changes as a function of the angle of incidence of the rays originating from said curved portion (20), and a second zone (25b) corresponding to the rays reflected by the flat portion (21) said reflector means for which the deflection angle is constant.  13. Signaling light according to any one of claims 10 to 12, characterized in that each prism has an inlet face (fe) perpendicular to the general plane of said ice and a reflection surface (fo) inclined by report to this plan.  14. Signaling light according to revendicaiton 13, characterized in that the reflection face (fo) is concave with respect to the rays it becomes.  15. Signaling light according to any one of claims 7 and 2, characterized in that said reflector means (40) are staggered with steps whose distance to the illuminating surface (35) of the light is decreasing from said bulb (9) towards the end of the housing (31) and in that said dioptric block (36) has a generally elliptical shaped ring-shaped cap whose axis coincides with the secondary axis IX-X), the surface outer of this block being smooth. while the inner surface has facets (3Sa to 39k) of general shape spherical annular portion.  16. Signaling light according to claim 15, characterized in that the profile of said outer surface (38) has a central portion (RS) whose curvature is more pronounced than an outer annular portion (ST).  Traffic light according to one of Claims 15 and 16, characterized in that the rungs (41a to 41f) of said reflecting means are connected to each other by generally convex reflective surfaces (42a to 42e) and in two portions inclined relative to each other and extending transversely in the housing (31) in the extension of one another.  18. Signaling light according to any one of the preceding claims, characterized in that the dioptric block (16,36) is colored to give the fire signaling function.  19. Signaling light according to claim 1, characterized in that said bulb (9,32) is placed at one end of the fire box.