Headlights for motor vehicles

Description

Field of the Invention

[0001] The invention relates to headlights for motor vehicles where the system with a light source, a refractor and a complex reflector provided with facets of parabolic cylinder shape is solved which forms a boundary of light and darkness towards to which the light beam is concentrated. A side diffusion of the light beam can be made by the reflector directly without any actions of the refractor optical elements for light diffusion.

Background of the Invention

[0002] The prior art headlights with a complex reflector without any optical deviation elements on the refractor use such facets of parabolic cylinder shape where a vertical deviation component is absent. A disadvantage of this solution is that a light beam is formed which does not illuminate sidewise the space up to the maximal visibility distance but to a shorter distance. This decreases the visibility distance of such a headlight, namely the visibility space to sides.

[0003] Deviation characteristics of a common headlight are roughly symmetric on the side of the nearer road boarder and the side of the more distant one. In case of a dimmed light it causes uneven road illumination as a consequence of imaging two brilliant light tracks on the road. Probability of a higher dazzling by dimmed lights also increases if the headlight which is nearer to the central line and eyes of the oncoming driver is virtually of the same luminous intensity as the more distant one.

[0004] The US patent 4 704 661 by Walter J.Kosmatka from November 3, 1987 discloses a multi-faceted reflector for a headlamp of a motor vehicle, the facets of which being placed entirely on the reflective surface of the reflector. The reflective surfaces are comprised of plurality of discrete reflector surfaces having right parabolic shape and of discrete simple rotated parabolic surfaces. This solution helps to improve the road illumination but there is an ongoing demand on further improving the road illumination. The disadvantage of this solution is that it only allows to change a character/ width of the diffusion of the light.

[0005] Also, in case of the same luminous intensity level and distribution of both usual headlights, the intensity of the space illumination of the nearer road boarder is relatively lower, what decreases the visibility distance and decreases optical guiding of a driver as a consequence of a lower luminance of this space if illuminated by dimmed and distance lights.

Summary of the Invention

[0006] The above mentioned drawbacks are removed in headlights according to the present invention, whereby each of them consists of a refractor, a light source and a reflector provided above the horizontal line with facets having the shape of parabolic cylinders with the forming profile situated in the basic paraboloidal reflector shape. Axes of the parabolic cylinders are not horizontal, but they are turned out of the headlight horizontal line. The parabolic cylinder length determines the side diffusion rate. At a certain length of parabolic cylinders, in a limit case, the refractor does not need to be provided with any optical elements for light diffusion, what is advantageous namely if the refractor is very inclined horizontally and vertically. In case of a headlight adjacent to the nearer road boarder, the facets on the side nearer to the road boarder are less inclined then the facets nearer to the road central line in relation to the headlight vertical line. The light beam formed by said facets is below the eyes level of an ongoing driver and so it does not cause any dazzling of ongoing traffic participants.

[0007] The facets that are nearer to the road central line in the headlight adjacent to the central line are less inclined then the facets that are nearer to the central line in the headlight adjacent to the nearer road boarder for the reason to prevent dazzling in a rear mirror and also to prevent dazzling of an ongoing driver by the headlight adjacent to the central line. The facets nearer to the road boarder in the headlight adjacent to the nearer road boarder are less inclined then the facets nearer to the road boarder in the headlight adjacent to the central line, also for the reason to prevent dazzling of an ongoing driver.

[0008] The so designed system of inclined facets forms a global light image in front of an automobile. The side space on the side of the nearer road boarder is illuminated more intensively by the headlight adjacent to the nearer road boarder and the side space on the side of the more distant road boarder by the headlight adjacent to the central line, whereby, visibility is increased in the space of the nearer and the more distant road boarders and optical guiding of a driver is so improved.

[0009] Each facet, divided by the contact line of the basic paraboloid profile is asymmetrical. The part which is nearer to the headlight vertical line is broader. From this follows that the light beam diffusion obliquely upwards is greater then that obliquely downwards, whereby dimmed light reach is improved, namely at sides of the light beam and road brightness is decreased at a small distance in front of the vehicle.

[0010] The headlight adjacent to the nearer road boarder has smaller facets width at the same sides with regard to the headlight vertical line and consequently a lower diffusion and a higher light concentration then the headlight adjacent to the central line. Thereby, visibility is increased in the space of the nearer road boarder and danger of dazzling a driver of an ongoing vehicle is decreased during an overshoot of the dimmed lights. The light beam homogenity and light brightness distribution on the road are also improved.

[0011] A single-filament or a twin-filament lamp or lighting arch of a gas discharge lamp can be used as the light source.

Brief Description of the Drawings

[0012] The invention is further illustrated with reference to the accompanying drawings, in which Figure 1 shows a front view of a pair of headlight reflectors with facets, Figure 2 shows a vertical section of a headlight, Figure 3 shows a lateral section of facets and Figure 4 shows a contour of a light track made by the facets on a testing wall.

Examples of the Invention Embodiment

[0013] Figure 1 shows a perspective view of the nearer road boarder and the central line. The headlight 1 is adjacent to the nearer road boarder and headlight 2 is adjacent to the road central line. Above the horizontal line z, the headlights are provided with facets 11, 12, 21, 22 having the shape of parabolic cylinders with creating profile B, C, situated in the basic parabolic reflector shape. In case of the headlight 1 adjacent to the nearer road boarder their inclination to the vertical line y is, α₁₁, α₁₂ and in case of the headlight 2 adjacent to the road central line is α₂₁, α₂₂, whereby the following is valid:







and

[0014] Figure 2 shows the vertical section A-A of a headlight composed of a reflector 3 with a basic paraboloidal shape 31 with a focal distance f and an apex V. The refractor 4 can be without any deviation elements and the dimmed light source 5 is placed so that the light source face 5 is at a distance Δf from the focus F of the reflector 3 has a value:

[0015] The light beam diffusion is given by the width of the direct line of facets w₁₁, w₁₂, w₂₁, w₂₂. The partial facet width on the side adjacent to the vertical line y of the headlight is greater then that on the opposite side. Consequently, according to Fig. 3 it follows that diffusion of the light beam obliquely upwards β_, ε is greater than that obliquely downwards γ_, δ:

[0016] The facet widths w₁₁, w₁₂ of the headlight 1 which is adjacent to the nearer road boarder are lower at the same side then those of facets w₂₁, w₂₂ of the headlight 2 adjacent to the central line.

[0017] The light beam diffusion coming from the headlight 1 is lower then that coming from the headlight 2. Thereby, illumination in the space of the nearer road boarder and optical guiding of a driver are improved and possibility to dazzle ongoing traffic participants is decreased.

[0018] In the above described example, the light source 5 is integrated in an assembly with a distance light source 6, which is situated in the vicinity of the focus F of the reflector 3.

[0019] In this headlights geometry layout, a global image is obtained showing increased photometric reach of the light beam and a more intensive illumination of the road boarders, what makes possible to improve visibility distance, improvement of probability that an obstruction in the automobile trajectory will be registered and prolongation of the time necessary for the driver's reaction to said obstruction.

Industrial Use

[0020] The headlight with a complex reflector according to this invention is determined to be used in illumination systems of motor vehicles, operated on road communications.

Claims

1. Headlights for motor vehicles consisting of a light source, a reflector (3) with a plurality of discrete reflective surfaces and a refractor (4), the refractor (4) being either entirely without any deviation elements or it is provided with optical elements of low deviation, the reflector (3) is provided above the horizontal line (z) with facets (11, 12, 21, 22) in the shape of parabolic cylinders with a creating profile (B, C) situated in the basic parabolic shape (31) of the reflector (3), with a focus distance (f) of the reflector (3), characterised by a set of two headlights (1,2), the facets (11,12,21,22) of which reflectors (3) have inclination with regard to the vertical line (y) of the headlight (1) to be incorporated adjacent to the nearer road boarder are defined by the values of the angle α₁₁ in the range 5° to 18° and the angle α₁₂ in the range 0° to 12°and the inclinations for the other headlight (2) to be incorporated adjacent to the road central line are defined by the values of the angle α₂₁ in the range 0° to 15° and of the angle α₂₂ in the range 0° to 9°   (1)
where:





and the dimmed light source (5) is at a distance Δf from the focus (F) of the reflector (3) with a value in the range 0.01.f to 0.26.f   (3)

2. Headlights according to claim 1, characterised in that the diffusion of a light beam (β, ε), formed by the width of the direct line of a part of the facets (11, 12, 21, 22) nearer to the vertical line (y) of the headlight is greater than the diffusion (γ, δ) formed by the facet parts(11, 12, 21, 22) more distant from the vertical line (y) of the headlight considering the penetration of the creating profile (B, C) of facets and of the basic paraboloide shape (31) of reflector (3):

3. Headlights according to claims 1 and 2, characterised in that the widths (w₁₁, w₁₂) of facets (11, 12) of the headlight (1) adjacent to the nearer road boarder are smaller at the same side with regard to the vertical line (y) of the headlight, then the widths (w₂₁, w₂₂) of facets (21, 22) of the headlight (2) adjacent to the road central line:

4. Headlights according to claims 1, 2 or 3, characterised in that in the proximity of the focus (F) of the reflector (3) a source (6) of distance light is placed.

Ansprüche

1. Scheinwerfer für Kraftfahrzeuge, bestehend aus einer Lichtquelle, einem Reflektor (3) mit mehreren diskreten reflektierenden Flächen und einem Refraktor (4), der entweder keine ablenkenden Elemente oder optische Elemente mit geringer Ablenkung aufweist, wobei der Reflektor (3) oberhalb der Horizontallinie (z) Facetten (11, 12, 21, 22) in Form von Parabolzylindern mit einem erzeugenden Profil (B, C) aufweist, das in der Parabol-Grundform (31) des Reflektors (3) liegt, und wobei der Reflektor (3) eine Brennweite (f) aufweist, gekennzeichnet durch eine Gruppe von zwei Scheinwerfern (1, 2), wobei die Facetten (11, 12, 21, 22) ihrer Reflektoren (3) Neigungen bezüglich der Vertikallinie (y) aufweisen, die für den näher zum Straßenrand einzubauenden Scheinwerfer (1) durch die Werte des Winkels α₁₁ im Bereich von 5° bis 18° und des Winkels α₁₂ im Bereich von 0° bis 12° und für den anderen, näher zur Straßenmittellinie einzubauenden Scheinwerfer (2) durch die Werte des Winkels α₂₁ im Bereich von 0° bis 15° und des Winkels α₂₂ im Bereich von 0° bis 9° definiert sind, wobei   (1)





und wobei die Abblendlichtquelle (5) vom Brennpunkt (F) des Reflektors (3) einen Abstand Δf im Bereich von 0,01·f bis 0,26·f aufweist.   (3)

2. Scheinwerfer nach Anspruch 1, dadurch gekennzeichnet, daß die Lichtstrahl-Streuung (β, ε), die von der Breite der direkten Linie eines näher an der Vertikallinie (y) des Scheinwerfers gelegenen Teils der Facetten (11, 12, 21, 22) erzeugt wird, angesichts der Durchdringung des erzeugenden Profils (B, C) der Facetten und der Parabol-Grundform (31) des Reflektors (3) größer ist als die Streuung (γ, δ), die von den von der Vertikallinie (y) des Scheinwerfers weiter entfernten Facettenteilen (11, 12, 21, 22) erzeugt wird:

3. Scheinwerfer nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Breiten (w₁₁, w₁₂) der Facetten (11, 12) des näher zum Straßenrand gelegenen Scheinwerfers (1) an der gleichen Seite bezüglich der Vertikallinie (y) des Scheinwerfers kleiner sind als die Breiten (w₁₁, w₁₂) der Facetten (21, 22) des näher an der Straßenmittellinie gelegenen Scheinwerfers (2):

4. Scheinwerfer nach Anspruch 1, 2 oder 3, dadurch gekennzeichnet, daß nahe dem Brennpunkt (F) des Reflektors (3) eine Fernlichtquelle (6) angeordnet ist.

Revendications

1. Phares destinés à des véhicules à moteur constitués d'une source de lumière, d'un réflecteur (3) comportant une pluralité de surfaces réfléchissantes séparées et d'un réfracteur (4), le réfracteur (4) étant soit entièrement dépourvu d'élément de déviation, soit muni d'éléments optiques de faible déviation, le réflecteur (3) est muni, au-dessus de la ligne horizontale (z), de facettes (11, 12, 21, 22) en forme de cylindres paraboliques présentant un profil de conception (B, C) situé dans la forme parabolique de base (31) du réflecteur (3), avec une distance (f) au foyer du réflecteur (3), caractérisés par un ensemble de deux phares (1, 2), les facettes (11, 12, 21, 22) desquels réflecteurs (3) présentent pour le phare (1) devrait être disposé de façon adjacente au bord de la route le plus proche des inclinaisons par rapport à la ligne verticale (y) de ce phare définies par les valeurs de l'angle α₁₁ dans la plage de 5° à 18° et de l'angle α₁₂ dans la plage de 0° à 12° et les inclinaisons pour l'autre phare (2) devant être disposé de façon adjacente à l'axe central de la route sont définies par les valeurs de l'angle α₂₁ dans la plage de 0° à 15° et de l'angle α₂₂ dans la plage de 0° à 9°   (1)
où :





et la source de feu de croisement (5) est à une distance Δf par rapport au foyer (F) du réflecteur (3) présentant une valeur dans la plage de 0,01.f à 0,26.f   (3).

2. Phares selon la revendication 1, caractérisés en ce que la diffusion d'un faisceau de lumière (β, ε), formé par la largeur de la ligne directe d'une partie des facettes (11, 12, 21, 22) plus proche de la ligne verticale (y) du phare est supérieure à la diffusion (γ, δ) formée par les parties de facettes (11, 12, 21, 22) plus distantes de la ligne verticale (y) du phare en considérant la pénétration du profil de conception (B, C) des facettes et de la forme parabolique de base (31) du réflecteur (3) :

3. Phares selon les revendications 1 et 2, caractérisés en ce que les largeurs (w₁₁, w₁₂) des facettes (11, 12) du phare (1) adjacent au bord le plus proche de la route sont plus petites, d'un même côté de la ligne verticale (y) du phare, que les largeurs (w₂₁, w₂₂) des facettes (21, 22) du phare (2) adjacent à l'axe centrale de la route :

4. Phares selon les revendications 1, 2 ou 3, caractérisés en ce qu'une source (6) de feu de route est placée à proximité du foyer (F) du réflecteur (3).

Drawing