US 3569961 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
'  SIGNALLING INDKIATOR LENS FOR MOTOR United States Patent n 1 3,569,961
 Inventor Jacques Ricard  References Cited Fontenay sur 8015, France UNITED STATES PATENTS gig-No 2: 1 :1 1969 1355 1 13,7o3 3/1939 Bolser 340/383k 1,942,136" 1/1934 Carter.... 340/383 .9, 7 mg i 2,850,716 9/1958 Smale 340/3333; Bobigny, France Primary Examiner-Harold I. Pitts  Priority Apr. 26, 1968 Attorney-Breitenfeld and Levine  France  149639 ABSTRACT: A motor vehicle signalling indicator having on Drawin Fi s the internal surface of its transparent or translucent window at g g least one group of concentric arcuate ridges. One side of each  US. Cl 340/383 ridge is located on a conical surface the apex of which is out-  Int. Cl t G08b 5/36 side the plane and spaced from the front to rear central win-  Field of Search 340/383 dow of the axis of the indicator.
in i, M. .111 W m HHIHHIH PATENTED MAR 915m SHEET 1 0F 3 INWNTOW 'mcawrs wcmw PATENTEI] MAR 9197:
SHEET 2 OF 3 mcq ues I mm 3 PATENTED m 91911 SHEET 3 [IF 3 INVENTOR T CQMES 'RICGRD SlGNAlLlLllNG HNDHCATGR LENS FGR MOTOR VEHHCLES I This invention relates to signalling indicators for motor vehicles the indicators being of the type comprising at least one light source, at least one reflector for reflecting in a controlled light beam, the light emitted by the source, and a translucent or transparent window for passage of the light beam.
The reflector is generally a parabolic reflector which reflects, through the window a beam of light rays parallel to the central axis of the indicator reflector the light source being substantially at the focal point of the reflector.
in practice, taking into account the position of the signalling indicators on a motor vehicle, it is important that the light leaving an indicator is concentrated in certain preferred directions, and the experimental norms of the indicators require, in a flat field located at a certain distance from the indicator, prescribed light intensities varying according to the different illuminated regions.
in order to obtain the necessary deflections of the light beam reflected by the reflector, it has already been proposed to provide the front window of the indicator with ridges provided on the outer side of this window, it has also been proposed to provide the interior side of the window with a Fresnel biprism in order to deflect the light coming directly from the light source.
These methods are rudimentary and not satisfactory in that they do not make possible a precise measurement of the light intensities in the field referred to.
The present invention proposes a method of obtaining different light intensities in the given field in a much more precise and exact manner by a novel and particular construction of the indicator window.
According to the present invention there is provided a signalling indicator for a motor vehicle, in which the window through which pass light rays is provided or formed on its internal side with at least one group of concentric, arcuate ridges, one side of each ridge located on a conical surface having its apex outside the plane of the window and spaced from the axis of the indicator.
Each ridge may comprise a side perpendicular to the light rays, the light passing through this side without deflection in order to strike the side located on the conical surface which constitutes a side of total reflection.
The side of each ridge located on the conical surface may be a refraction side, the light leaving through the outer side of the window which constitutes the outlet side common to all ridges.
The arcuate ridges of a group of concentric ridges can deflect the light in a given direction, the light reflected by an entire ridge being reflected only in one direction. The angle of deflection imparted by each ridge may vary continuously along the length of the ridge according to certain angular limits; preferably then, all the ridges transmit the light in the same angular limits so that the light intensity is increasedin all directions between these limits.
An embodiment of the present invention will be described, by way of example, with reference to the accompanying drawings, in which:
FlG. l and 2 illustrate diagrammatically the constitution of an indicator according to the present invention, in front view and central horizontal section;
FIG. 3 illustrates the method of action of a ridge provided on the front window of the indicator in order that light rays emitted by the light source and striking this ridge leave the window as horizontal light rays forming a given angle with the central axis of the indicator.
H6. 4 is a diagrammatic section of the window of the indicator;
FIG. 5 is a view of the interior of the window of FlG. 4 showing the system of ridges;
MG. 6 is a section on the line Vl-Vi of FIG. 4;
HO. 7 is a section on the line Vll-Vll of FIG. 5;
FlG. 8 is a section on the line Vlll-Vlll of HO. 5; HO. 9 is a section on the line lX-lX of FIG. 5; and
FIG. it) illustrates the distribution of the different areas of illumination in a predetennined plane in front of the indicator.
Referring to FIGS. 1 and 2 the indicator according to the present invention comprises, arranged about a central axis of symmetry MO, a window G, a light source centered at M, and a reflector R, the focal point of which is near to M. Although it may be slightly curved, the window G may be considered in effect as disposed wholly in the vertical plane X 02 characteristically the internal side of the window G, comprises to its right and to its left, for an observer looking at the indicator, partially circular ridges Sd and Sg respectively shown diagrammatically on FIGS. 1 and 2.
In the particular example, chosen, these ridges are disposed and arranged such that they receive the light which comes directly from M and reflect it at a constant angle 0 relative to horizontal light rays parallel with the axis M0, the deflection taking place, for an observer facing the window, towards the right for the ridges S d and towards the left for the ridges Sg. For this purpose each of the ridges Sd, 53 comprises a face a tangential to a sphere, the centers of the respective spheres being C d and C g respectively. These centers are outside the central axis MO of the indicator and outside the plane of the window G.
In other words, it can be said that each side a of a ridge is on a conical surface tangential to the sphere on the general line of the ridge.
FIG. 3 explains the above construction. ln this FlG., the references used above are repeated. S, is the right-hand ridge. T and T are two points on this ridge, the light rays M and M leaving the window as horizontal rays T and) T forming a given angle of deflection 0 with the horizontals T ll and T l-l parallel with the central axis MO of the indicator.
This reflective etfect of the ridge S, is due to the presence of a reflection side a which is tangential to a sphere with the center C d (or, which is the same thing, traced on the conecover of this sphere).
The center C d of the sphere stands out on the plane of the window at Cd. The plane XC d Z. is parallel with the plane of the window.
Under these conditions, the desired object (constancy of the angle 0) is attained if the angle OMCd is equal to 6 and if the distance C d M from the center of the sphere to the light source is equal to:
IN WHICH L is the distance from M to the plane of the window and d the distance of the ridge to the axis of the indicator, taken in the horizontal plane of this axis.
It can be seen from the above that the position of C d is determined precisely and exactly.
It is to understood that FlGS. l, 2 and 3 have only been given as an example to make it understood how the present invention can be put into operation. Circular ridges having reflection side a for a given horizontal reflection or deflection are only examples.
in general terms, the invention applies to all the systems of circular ridges arranged on the internal side of the indicator for obtaining a predetermined reflection. This reflection or deflection may be the same for all the ridges of a group of ridges. It may vary from one ridge to another, or from one group of ridges to another. On the other hand, the side of each ridge arranged on the conical side may be either a side of total reflection, as in the example given above, or a side of refraction.
In a particularly interesting embodiment, there can be used a system of circular ridges, whereof the angle of reflection or deflection (for example horizontal deviation) of the light varies continuously along the length of a ridge. Ridges of this kind enlarge an existing image of an angle which is a function of the position of the center of the sphere (or of the apex of the cone) defining each ridge.
FIGS. 4 to 9 illustrate a specific construction of the indica- I01.
characteristically, on the interior side of the indicator window there are provided a series of ridges.
The ridges S to S on the one hand, and 8, to S,, on the other hand, have their apparent center at C,. That is to say these ridges tangential a side a (of reflection or refraction) tangential to a sphere (or located on a cone) the center of which or the apex of which stands out on the window at the point C.
The ridges S to 8,0 are apparently centered at C'2. The ridges S to S are apparently centered at C3. The ridges S, are apparently centered at C4 and the ridges S, at C'5.
In the case of the ridges S and S the sides a traced on a conical face, are sides of total reflection, the ridges having inlet sides b perpendicular to the light ray coming directly from the source (not shown).
In the case of the ridges S, and S and as can be seen better in FIG. 7, the sides a provided on conical surfaces, are inlet sides acting by refraction in cooperation with the outer side of the window constituting the common outlet for these ridges.
FIG. 10 illustrates, in a given field, the effects of the different ridges. The given field is defined about the axis of the indicator by the horizontal angular deflections and the vertical angular deflections. In the given field, the ridges S, effect the illumination of the area 2,, the ridges S, the illumination of the zone Z the ridges S to S the illumination of Z and the ridges S the S the illumination of Z lclaim:
l. A signalling indicator for a motor vehicle, in which the window through which pass light rays is provided or formed on its internal side with a least one group of concentric, arcuate ridges, one side of each ridge being located on a conical surface having its apex outside the plane of the window and spaced from the front to rear central axis of the indicator.
2. An indicator according to claim 1, in which each ridge has another side perpendicular to the path of the light rays, so that the light rays pass through said other side without deflection and strike the side located on the conical surface, said latter side constituting a side of total reflection.
3. An indicator according to claim 2, in which the side of each ridge located on the conical surface is a side of refraction, the light leaving through the outer side of the window, said outer side constituting the outlet side common to the ridges.
4. An indicator according to claim 1, in which the ridges of one group are ridges for horizontal deflection and having, relative to the axis of the indicator, an angle of deflection which is constant along the length of each ridge and for all the ridges of the group.
5. An indicator according to claim I, in which the ridges produce a deflection according to a variable angle within given limits, along the length of each ridge.