FR2642144A1 - IMPROVEMENTS IN ICE HEADS HAVING DEVIATE ELEMENTS OF DIFFERENT PROFILES - Google Patents

Abstract

The present invention relates to a headlamp lens for a motor vehicle, of the type comprising, in at least first and second neighboring zones Za, Zb, at least a first and a second elongated deflector elements Da, Db, each deflector element of a zone having a constant profile determined independently of the constant profile of another deflector element located opposite in the other zone. It is characterized in that it further comprises, in at least one transition zone Zt situated between the first and second zones, at least one connecting deflector element Dt defined by a continuous surface which rests at one end on the profile Pa of a first associated deflector element and at the opposite end on the profile Pb of a second associated deflector element, located opposite the first. The invention makes it possible to produce glasses having improved optical and aesthetic properties.

Description

The present invention relates to projectors,

  especially for motor vehicles.

  It relates more particularly to improvements

  the closing windows of these headlamps.

  Conventionally, the closing glass of a projector is formed of several zones each having a well-defined optical function. To perform each function, deflection elements are formed on the ice, in particular in the form of prisms or striations, which present perpendicular to the

  the plane of the ice a profile that remains invariant.

  Thus, at the transition between two zones, there is a difference between the profiles of the respective deviating elements of the two zones, and this difference gives rise to discontinuities which are disadvantageous for several reasons. On the one hand, the surfaces of the ice at these discontinuities are likely to deflect the light rays received from the reflector upwards, which may dazzle drivers of vehicles coming in the opposite direction. In addition, these discontinuities cause on the ice the presence of light lines corresponding to the various transitions between the zones, which is aesthetically undesirable. On the other hand, sudden changes in the way in which the light is going to be deflected by the ice can cause inhomogeneities in the beam. Finally, it should be mentioned that the locations of the separations between zones are currently determined closely according to the characteristics and the position of the associated reflector. As a result, the same ice can only be associated with one single position

determined reflector.

  We already know. in the prior art of ice in which this kind of discontinuity is avoided by giving streaks of a well-defined nature a profile which evolves continuously between a given starting profile and a given arrival profile. For example, patents

  French Nos. 1,187,443, 2,428,204 and 2,432,678.

  However, each of these patents applies exzlusively to particular cases of streaks. In particular, the patent No. 1,187,443 is limited to grooves whose thickness and width decrease in a given direction. Patent No. 2,428,204 teaches streaks whose radius and width vary continuously. Finally, Patent No. 2,432,678 relates to parallel cylindrical grooves whose depressions or reliefs of separation are progressively reduced by cutting.

  appropriate tool to perform them.

  Thus, in all known cases, these are only streaks of evolutionary profile, that is to say offering a spreading of the

  light that varies as one moves along their length.

  Thus the state of the art, limited to the particular case

  binding rectilinear streaks with a circular profile, gives no indication as to how to unite, without discontinuities, profiled deflection elements of types and

  completely arbitrary orientations.

  The present invention aims to remedy these shortcomings of the known art and to propose a projector lens in which it is possible to ensure continuity between various areas of prisms, streaks or the like while preserving a

  full freedom in the design of these various areas.

  For this purpose, the present invention relates to a motor vehicle headlamp, of the type comprising, in at least first and second adjacent zones, at least a first and a second elongate deflection elements, each deflecting element of a zone having a constant profile determined independently of the constant profile of another deflector element located opposite the other zone, characterized in that it furthermore comprises, in at least one transition zone situated between the first and second zones at least one connecting deflection element defined by a continuous surface which is supported at one end on the profile of a first associated deflection element and at the opposite end on the profile of a second element

  associated deviator, located opposite the first.

  Other aspects, purposes and advantages of this

  invention will appear better on reading the description

  The following is a description of preferred embodiments thereof, given by way of example and with reference to the accompanying drawings, in which: FIG. 1a is a perspective view of a transition between two striation zones of a According to the known technique, FIG. 1b is a perspective view illustrating a first connection principle of the present invention adapted to the case of FIG. 1a, FIG. 2a is a plan view of another known transition. 2b is a plan view illustrating a second connection principle of the present invention adapted to the case of FIG. 2a; FIG. 3 is a perspective view of a first 4 is a perspective view of a second example of a complex strip made in accordance with the present invention, and FIG. face of an ice cream

  projector made according to the invention.

  Referring firstly to Figure la, there is illustrated the transition between two zones Za and Zb of a known projector closure glass. The zone Za comprises one or more deviating elements Da (only one being illustrated) constituted by prisms whose individual section Sa is approximately a right triangle. Zone Zb comprises one or more deflection elements Db consisting of convex striations, for example cylindrical striations,

  with section Sb as illustrated.

  The sections Sa and Sb being different, the abrupt transition between zones Za and Zb creates draft surfaces T where the two sections Sa and Sb do not feel opposite each other, as indicated, these Surfaces are disadvantageous in that they create parasitic deviations from the light rays coming from the reflector, the rays thus dexed dazzle the drivers of the vehicles -4 traveling in the opposite direction. In addition, the sudden change in light deflection characteristics by the ice can cause inhomogeneities in the beam. Finally, these brutal transitions generate on the ice brilliant lines that are not desirable on the aesthetic level. It can be noted that, in this example, the Da deviators

  and Db have the same pitch p (width) and are aligned with each other.

  Referring now to FIG. 1b, it is proposed in accordance with the present invention to create between the deviating zones Za and Zb a transition zone Zt whose object is to ensure a progressive and continuous evolution between

sections Sa and Sb.

  In this example, each connecting deflection element Dt of the transition zone Zt has a width equal to p and its outer surface is a regulated surface generated by a set of straight lines all parallel to the yOz plane and resting on the outer profile Pa of each prism Da of the zone Za at a first end and resting on the external profile Pb of each stripe Db of the zone Zb at the opposite end, these straight lines being by

  elsewhere contained in planes parallel to yOz.

  Moreover, the transition zone Zt has a length 1 in the direction of the deflection elements; this length can be chosen in practice according to the

  difference between sections Sa and Sb along the axis Ov.

  From a mathematical point of view, the outer surface of the transition zone of each connecting deflection element Dt can be given in this case by the following equation: v = (lz / l) .Fa (x) + (z / 1) .Fb (x) (1) or [O, x, v, z] is the orthonormal coordinate system as shown, Fa (x} is the function in (x, v) of the Pa profile in this frame, and

  Fb (x) is the function in (x, y) of the profile Pb in this frame.

  We thus determine a linear variation along z of the

  profile of the element Dt between Fa (x) and Fb (x).

  Of course, the particular solution adopted

above it is not the only one possible.

  For example, to ensure a nonlinear transition between the two profiles, and in particular to avoid any break in the surface of a deviating band formed by the succession of elements Da, Dt and Db, it can be used to define the surface of deviating elements Dt the following equation: y = A (u, v) .Fa (v) B (u, v) .Fb (V) (2) o Fa and Fb are as defined above, A (u, v ) and B (u, v) are functions such that: if u = 0, A (u, v-) = 1 and B (u, v) = 0 if u = 1, A (u, v) = 0 and B (u, v) = 1, and

u = z / l and v = x.

  Although the example described above is relative to the transition between a prism and a convex stripe, it will be clear to the specialist that the invention can be applied to any other form of deflection element. In this respect, the mathematical approach indicated above adapts to any pair of functions (Fa, Fb) defining the

profiles in zones Za and Zb.

  FIG. 2a illustrates the case where the deflection elements Da of a first zone Za and the deflection elements Db of a second zone Zb adjacent to the first zone and separated from it by a straight line dab do not have the same direction, but their directions make an angle noted ab between them. In this case, according to another essential aspect of the invention, and as illustrated in FIG. 2b, there is provided between the two zones Za and Zb a transition zone Zt which is delimited on the one hand by two straight lines da and db which are respectively perpendicular to the direction of the prisms Da and to the direction of the striations Db and secondly by two arcs of circles ci and ce, respectively inner and outer, which ensure the continuous transition and without break between 's corresponding limits of zones Za and Zb, being centered on the point Q situated at the intersection of the lines da and db. The individual deflection elements Dt of this transition zone each follow a circular arc which is also centered in Q. Just as in the embodiment of FIG. 1b, each deviating element Dt of the transition zone Zt sees its profile gradually change from Pa profile of zone Za to Pb profile of zone Zb. But in this case it is its radial profile with respect to Q. In a first concrete embodiment, the evolution of the profile can be linear as a function of the rotation angle O around the point Q. This linear evolution can be defined mathematically by the following equation: v15 = [(Oa) / (b- a)]. Fb (r) - [(Eb-e) / (Eb-Oa) J.Fa ( r) (3) where Fa (r) and Fb (r) are the functions in (r, y) of the profiles Pa and Pb along the lines da and db, (G, r) are the polar coordinates in the plane of the ice, 2C with respect to point Q and a reference line dr, v is the altitude with respect to the plane of the ice, Ga is the angle of the line da with respect to dr and

  Ob is the angle of the line db with respect to dr.

  As in the previous example, the evolution of the profile of the deviating elements in the transition zone Zt may also not be linear. In this case, we can define the outer surface of these deviating elements by the following equation: y = A (u, v) .Fa (v) - B (u, v) .Fb (v) (4) o Fa and Fb are as defined above, A (u, v) and B (u, v) are functions such that: if u = 0. A (u, v) = 1 and B (u, v) = 0 if u = 1, A (u, v) = 0 and B (u, v) = 1, and u = (- a) / (b-ea) and

v = r.

  FIGS. 3 and 4 show complex deflecting elements or deviating strips made

  according to the present invention.

  The deflecting strip of FIG. 3 comprises, in succession, a rectilinear convex cylindrical stripe Da in the zone Za, followed in a straight transition zone Zt of a transition element Dt whose profile progressively passes from the convex shape of the streak. Da to the equally convex form of a streak Dc located in a zone Zc which follows the zone Zt. As can be seen, the streak Dc is in fact a "prism-stria", that is to say that its face is cylindrical convex, but the axis of the cylinder is offset laterally with respect to the median plane of the streak. Such a "prism-stria" conventionally ensures a dispersion of the light by giving it a predetermined average deviation. It is also observed, and this constitutes a variant of the present invention, that there is a sudden change in direction (angle Y Y of the deviating band at the boundary between the elements Dt and Dc. In this concrete example, the deflection element Dt is straight, and is designed according to the principles described with reference to Figure lb. Figure 4 illustrates a deflecting band comprising in succession a cylindrical convex streak Da, followed by a

  first deflection element Dt connection with a prism-

  streak Dd. A second connecting deflection element Dt 'connects the element Dd to a curved prism Df, obtained by rotating on an angle ef around the point Q of the prismatic section Sf as shown. The next element, noted Df ', is a prism of the same section as the prism Df, but this time rectilinear. Finally a third transition element Dt "ensures the transition with a new convex streak

cylindrical Dc.

  All elements, except for the Df prism, are rectilinear. The three transition elements are here again made in accordance with the principles explained above with reference to FIG. FIG. 5 illustrates an example of a projector lens G made in accordance with the teachings of the present invention, and adapted to a dipped beam at

European standard cut.

  In this figure, the non-hatched areas are areas in which the deviating elements have a constant section, whereas the hatched areas are transition zones, in which the deviating elements are

  connection elements designed in accordance with the invention.

  This figure also shows the profiles of the various deflection elements. In this respect, in order to avoid

  to weigh down the present description, it will be considered that

  all the indications in FIG. 5 relating to the disposition of the deflection elements, their dimensions and

  Their respective profiles are included in the description.

  It can be observed that the deflecting elements are divided into juxtaposed bands which each have no discontinuity. As a result, the disadvantages mentioned in the introduction are removed, and this while retaining full freedom for the design of the various

individual deflection elements.

  In addition, some of these strips comprise a plurality of constant section deviators separated by a plurality of connection deviators,

  designed according to the invention.

  It can also be seen that in some bands there are two juxtaposed junction elements (for example Dt, and Dt2), and in addition some of these elements have a substantial length. In other words, the connection striations according to the invention can be used not only for their continuous connection properties between deviating elements of constant profiles but different from each other, but also for their properties of deviation of light from a 3 which varies as one moves along the element. Of course, the present invention is not limited to the embodiments described above and shown in the drawings. In particular, it applies to deviating elements of types, widths and

any lengths.

  In addition, the prisms or striations can be formed indifferently hollow and relief, and indifferently on the inner or outer face of the ice, these choices being dictated in particular by the type of deviation sought and by

the regulations to be respected.

2642144

Claims (9)

  Motor vehicle headlamp glazing, of the type comprising, in at least first and second adjacent zones (Za, Zb), at least a first and a second elongate deflection element (Da, Db), each deflecting element of a zone having a constant profile determined independently of the constant profile of another deflection element located opposite the other zone, characterized in that it further comprises, in at least one transition zone (Zt) situated between the first and second zones, at least one connecting deflection element (Dt) defined by a continuous surface which is supported at one end on the profile (Pa) of a first associated deflection element and at the opposite end on the profile (Pb) of a second associated deviating element, located opposite the first one.   l - 2. Projector lens according to claim 1, wherein the first and second deviating elements facing each other (Da, Db) have the same width (p) and are in alignment with each other, characterized in that each connecting deflection element (Dt) has the same width as the first and second associated first and second deflection elements and extends in their alignment.   3. Projector lens according to claim 2, characterized in that the surface of a connecting deflection element (Dt) is defined by the following equation: y = (lz / l) .Fa (x) + (z / l) .Fb (x) (1) in the orthonormal coordinate system [Ox, y, z] such that xOz is the plane of the ice, and Oz is parallel to the direction of the deflection elements, where 1 is the length following Oz of the connecting deflection element, and Fa {x) and Fb (x) are the functions in (x, y) of the profiles (Pa, Pb) of the associated deviating elements of the first and second zones. there 2642144 4. Projector glass according to claim 2, characterized in that the surface of a connecting deflection element is defined by the following equation: y = A (u, v). Fa (v) - B (u, v) .Fb (v) (2) in the orthonormal coordinate system [O, x, y, z] such that xOz is the plane of ice, and Oz is parallel to the direction of deviating elements, where Fa (x) and Fb (x) are the functions in (x, y) of the profiles (Pa, Pb) of the associated deviating elements of the first and second zones, A (u, v) and B (u, v) are continuous functions such that: if u = 0, A (u, v) = 1 and B (u, v) = Q sl u = 1, A (u, v) = O and B (u, v) ) = 1, and u = z / l and v = x, 1 being the following length Oz of the connection deflection element. 5. Projector lens according to claim 1, wherein the first and second deviating elements facing each other (Da, Db) have the same width and have directions that are inclined relative to one another (Oab), characterized in that each connecting deflection element (Dt) has the same width as the first and second deflection elements   associated and extends in an arc between them.   6. - projector lens according to claim 5, characterized in that the surface of a connecting deflection element (Dt) is defined by the following equation: y = [(e-ea) / (eb-oa)] .Fb (r) + [(eb-O) / (b- @ a)]. Fa (r) (3) in the frame [Q, r, O, y] such that [Q, r, e] defines the plane of the ice, Oy is perpendicular to this plane, and -Q is the point of intersection of two straight lines (da, db) perpendicular to the directions of the first and second deviating elements, where a and b are the angles defined by the two straight with respect to a reference line dr, and Fa (r) and Fb (r) are the functions (r, y) in radial planes transverse to the ice of the profiles of the first and second deflection elements associated with the deflection element connection. 7. Projector lens according to claim 5, characterized in that the surface of a connecting deflection element is defined by the following equation: y = A (u, v) .Fa (v) + B (u, v ) .Fb (v) (4) in the frame [Q, r, G, v) such that qae [Q, r, E] defines the plane of the ice, Oy is perpendicular to this plane, and Q is the point of intersection of two straight lines (da, db) perpendicular to the directions of the first and second deflection elements, where Fafr) and Fb (r) are the functions (r, v) in radial planes transverse to the ice of the profiles of the first and second deviating elements associated with the connection deviating element, A (u, v) and B (u, v) are continuous functions such that: u = 0, A (u, v) = 1 and B (u, v) = 0 if u = 1, A (u, v) = 0 and B (u, v) = 1, with u = (G-ea) / (Ob- a) and v = r, and sa and eb are the angles defined by said two straight   relative to a reference line dr.   8. Projector window according to one of the claims   preceding, characterized in that each deviating element with constant section (Da, Db) is selected from the group   including prisms, streaks and prisms-streaks.   9. Projector window according to one of the claims   prior art, characterized in that it comprises a plurality of juxtaposed bands of deflection elements, at least some of which comprise zones of constant profile deflection elements (Za-Zf) separated by transition zones (Zt, Zt ', Zt "), the locations of the boundaries between the constant profile deviation zones and the transition zones being determined so   independent of one band to another.