WO2013139962A1

WO2013139962A1 - Optical element for a vehicle light

Info

Publication number: WO2013139962A1
Application number: PCT/EP2013/056070
Authority: WO
Inventors: Henning Kiel; Patrick Wegener
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2012-03-22
Filing date: 2013-03-22
Publication date: 2013-09-26
Also published as: KR101722825B1; DE102012005826A1; CN104302966A; CN104302966B; KR20140124391A

Abstract

The invention relates to an optical element (6) for a vehicle light (1), comprising a light-incoupling surface (7) for coupling in the light emitted by a light source (3) of the vehicle light (1), and an outcoupling structure (8) which alters the directions of the incoupled light beams (L1, L2) such that an emission pattern is produced which differs from the emission pattern of the light emitted by the light source (3) of the vehicle light (1). The claimed optical element (6) is characterised in that the outcoupling structure (8) comprises a plurality of facet surfaces (9) which couple out light beams (L1, L2) at an emission angle β that is a function of the specific angular orientation α of the facet surface (9), said facet surfaces (9) being arranged at different angles α to one another in a non-repeating pattern.

Description

description

Optical element for a vehicle light

The present invention relates to an optical element for a vehicle lamp with a light input surface for coupling the light beams of a light source of the vehicle lamp and a coupling-out structure. In the coupling-out structure, the directions of the coupled-in light beams are changed so as to produce a radiation characteristic which differs from the emission characteristic of the light emission of the light source of the vehicle lamp.

Vehicle lights contribute increasingly to the design of the vehicle. The design of the vehicle lights is to give the vehicle in particular a characteristic appearance, which is easily recognized and by which the vehicle differs from the design of other vehicles. Furthermore, it make the space conditions for the vehicle lights of the vehicle, especially for the

Rear lights and headlamps, required that the structure of the lights is very compact and little space remains for the lighting surfaces of the lighting devices.

A vehicle lamp arrangement is known from DE 10 2004 053 643 A1, in which the cover has a light-directing optical structure. This structure has sawtooth-like projections which are each associated with a light emitting diode and this at least

overlap in sections.

From DE 39 25 999 A1 a signal light is known in which an optical disc is arranged between the light source and a cover. The cover has optical means in the form of a so-called pillow look. The optical disk expands in the central area, the almost parallel light rays, while in the outdoor areas

Light rays are less dilated.

The present invention is based on the technical problem of providing an optical element and a vehicle lamp with such an optical element, which in a Light emission of the vehicle lamp can provide a light function of the vehicle and which gives the vehicle lamp a particularly characteristic appearance.

According to the invention, this problem is solved by an optical element with the features of

Claim 1 and a vehicle lamp solved with such an optical element. Advantageous embodiments and further developments emerge from the dependent claims.

The optical element according to the invention is characterized in that the coupling-out structure comprises a multiplicity of facet surfaces in which light beams are coupled out in an emission angle that depends on the respective angular orientation of the facet surface. The facet surfaces are arranged in a partial region of the coupling-out structure at different angles to one another in a non-repeating pattern.

The faceted surfaces of the optical element give the vehicle lamp a particularly characteristic appearance for the viewer. The arrangement and orientation of

Facet surfaces make it possible to generate a defined radiation characteristic for a light function, which however is characterized by random, contrast-rich structures. In this case, in particular a regular structure, as is usually used in the case of light disks or intermediate light disks, is avoided in a subregion of the coupling-out structure. The observer does not perceive a uniform luminous surface, but especially with varying viewing positions and viewing angles a glittering effect, which gives the vehicle lamp another special characteristic and makes the vehicle lamp recognizable to the beholder again.

Preferably, the subregion of the coupling-out structure, in which the facet surfaces are arranged at different angles to one another in a non-repeating pattern, makes up at least 30% of the coupling-out structure. Particularly preferably, the subregion makes up exactly 30% of the coupling-out structure. Furthermore, the subregion preferably makes at least 40% or 50% and particularly preferably exactly 50% of the

Out coupling structure. Furthermore, the subregion of the coupling-out structure in which the facet surfaces are arranged at different angles to one another in a non-repeating pattern preferably constitutes at least 60%, at least 70%, at least 80% or at least 90% of the coupling-out structure. Particularly preferably, the subarea makes up exactly 70% of the coupling-out structure. In a further preferred embodiment, the partial area corresponds to the entire

Decoupling structure.

By the facet surfaces is advantageously also achieved that arranged behind the optical element further elements of the vehicle lamp, such as the light sources and reflectors, are not visible to the viewer or laminated by the optical element.

According to one embodiment of the optical element according to the invention, the distribution of the emission angles generated by the individual facet surfaces is of the one to be generated

Radiation characteristic set. However, the angular orientations of the individual facet surfaces to each other are randomly arranged. It is thus given a certain emission characteristic, for example, a specific light function of the vehicle. This light function may be, for example, the taillight function, the function of the direction indicator of the vehicle or the reversing light of the vehicle. It may also be a light function of the vehicle headlight, such as the low beam or the high beam. From this radiation characteristic results, which light intensity is to be emitted at which angle. Since the facet surface, from which a certain light intensity is radiated at a certain angle, is arbitrary, a large number of possible arrangements of the angular orientations of the facet surfaces results. According to the invention, a random arrangement of the angular orientations of the facet surfaces is chosen, which is the

Secondary condition is sufficient that the desired radiation characteristic is generated.

According to a further embodiment of the optical element, the facet surfaces are flat. The individual facet surfaces are connected by edges. The radius of curvature of these edges is in particular less than 4 mm. By this configuration of

Facet surfaces is advantageously enhanced the glittering effect for the viewer.

According to a further embodiment of the optical element according to the invention, the edges are aligned parallel to each other. In this way, for example, an elongated irregular zigzag structure can be produced. The length of the facet surfaces between the edges to adjacent facet surfaces is in particular greater than the thickness of the

Optic element. The thickness of the optical element results from the distance of opposing surfaces on the Lichteinkoppel- and Lichtauskoppelseite. The decoupling structure can be provided both on the coupling side and on the decoupling side. However, it is preferably provided on the light output side. Since the coupling-out structure of From the coupling side of the optical element gives an irregular structure, the average thickness is considered on this page.

According to a further embodiment of the optical element according to the invention, the distance between the edges of the facet surfaces in a direction perpendicular to the thickness of the optical element is always the same. The irregularity of the facet surfaces is thus achieved via the angular orientation of the facet surfaces. In the projection of the facet surface in a plane which is perpendicular to the thickness direction of the optical element, thus, a regular pattern may result. The non-repeating pattern results with respect to the angular orientations of the facet surfaces. The angular orientation is selected at random, but, as explained above, certain secondary conditions for generating a defined emission characteristic can be taken into account.

According to a further embodiment of the optical element according to the invention, the distance of the edges of the facet surfaces from an average value of the position of the edges in the direction of the thickness of the optical element, for. From the mean thickness of the optical element, as follows: A maximum distance M from the mean is determined. This maximum distance M is necessarily smaller than the thickness of the optical element. For adjoining ones

Facet surfaces are generated random numbers p between 0 and M. For successive, ie adjacent facet surfaces, the positive and negative values of the successive random numbers p are alternately taken as the distance value a of the respective facet surface. The edges of the facet surfaces are then arranged at the respective distance values a. The distance values a determine the angular orientation of the facet surface, since the distance between the edges in the direction perpendicular to the thickness of the optical element is the same. The distance perpendicular to the thickness of the optical element and the

Distance value a thus define a right-angled triangle in cross-section whose hypotenuse is the facet area.

According to a development of this method for determining the distance of the edges of the facet surface from the mean value of the position of the edges in the direction of the thickness of the

Optics elements are only used those random numbers for generating the distance value for which the deviation from the random number of the preceding distance value does not exceed a defined percentage, for example 10%. In this way, too large irregularities can be avoided in an advantageous manner. According to another embodiment of the optical element according to the invention, a regular structure known per se, which generates the desired emission characteristic, is used. For example, a per se known cushion optics can be considered, which generates the desired radiation characteristic. This structure is cut n times and the curvatures are linearized to give flat surfaces with a certain angular orientation. The resulting facet surfaces now have a regular structure. In the final step, the facet faces are randomly arranged. Due to the angular orientation in the facet surface, the emission characteristic is retained, but for the observer there is no longer a regular decoupling structure.

Finally, according to the invention, a vehicle lamp is provided with the above-described optical element. The optical element can be used as an intermediate lens in the

Vehicle light to be arranged. However, it is also possible that the optical element forms a lens of the vehicle lamp.

The invention will now be explained with reference to an embodiment with reference to the drawings.

Figure 1 shows the structure of an embodiment of the invention

Vehicle light

FIG. 2 shows a detail of a cross section of an embodiment of the invention

Optics invention and

Figure 3 shows a section of the arrangement of the optical element in one

Embodiment of the vehicle lamp.

In Fig. 1, an embodiment of the vehicle lamp 1 according to the invention is shown. In the vehicle light 1 may be a tail light or a headlight of a

Act motor vehicle.

The vehicle lamp 1 comprises a housing 2, which is closed to the outside by a transparent clear lens cover 5 formed in clear glass optics.

Within the housing 2, a light source 3 is arranged, which is electrically connected to a light control device (not shown). Further, within the housing 2 is a Reflector 4 is arranged so that the light emitted from the light source 3 is reflected in parallel in the direction of the light finishing disc 5.

Between the light source 3 and the reflector 4 on the one hand and the light finishing disc 5 on the other hand, an optical element 6 is arranged as an intermediate lens. The optical element 6 has a light input 3 facing the light input surface 7. About these

Lichteinkoppelfläche 7, the light emitted by the light source 3 is coupled into the optical element 6. On the side of the optical element 6 facing away from the light incidence surface 7, a coupling-out structure 6 facing the light-closing disk 5 is formed. By the

Auskoppelstruktur 8, the directions of the coupled light beams are changed so that a radiation pattern is generated, which differs from the emission characteristics of the light emission of the light source 3 of the vehicle lamp 1 and the light source 3 in conjunction with the reflector 4. According to another embodiment, the optical element does not form an intermediate lens, but the Lichtabschlussscheibe.

The coupling-out structure 8 has a plurality of planar facet surfaces 9, in which light beams are coupled out in a certain angle of radiation, which depends on the respective angular orientation of the facet surface, as will be explained later. The

Facet surfaces 9 are arranged in a partial region 12 of the coupling-out structure 8 at different angles to one another in a non-repeating pattern. The

Angular orientations of the facet surfaces 9 are arranged in particular in a random pattern. In this exemplary embodiment, the partial area 12 extends over the entire coupling-out structure 8, thus making up 100% of the coupling-out structure 8.

With reference to FIG. 2, the coupling-out structure 8 of the optical element 6 is explained in detail:

2, a cross section through a plate-shaped optical element 6 is shown. Of the

Reflector 4 meet the exemplified light beams L1 and L2 on the

Light input surface 7, which is a flat surface in the illustrated embodiment of the optical element 6. The light beams L1 and L2 in particular impinge perpendicularly on the light incoupling surface 7, so that they are not changed in their direction when they enter the optical element 6. Subsequently, the light beams L1 and L2 pass through the transparent optical element 6 and hit on the other side of the optical element 6 on the

Facet surfaces 9 of the decoupling structure 8. In Fig. 2, four facet surfaces 9-1, 9-2, 9-3 and 9-4 are shown by way of example. As shown in FIG. 3, the decoupling structure 8 comprises a plurality of elongate sections extending in the z-direction with adjacent facet surfaces 9. In the z-direction, adjacent facet surfaces 9 are connected to one another by edges 11. The edges 1 1 are aligned parallel to each other. The edges 1 1 resulting from adjoining facet surfaces 9 have substantially no rounding, the radius of curvature is in particular less than 4 mm.

Essential for the radiation characteristic generated by the optical element 6 is the angle a, which include the individual facet surfaces 9 with a plane parallel to the

Light input surface 7 is. The angles α of the facet surfaces 9 namely determine the

Beam angle ß of the light rays at the exit from the optical element 6 in the

Facet surfaces 9.

In Fig. 2, the angles α-ι to a ₄ are shown for the facet surfaces 9-1 to 9-4. From the angles α-ι and a ₄ results for the light beams L1 and L2, for example, the

Beam angle ß-ι and ß ₂ .

The angles α for the orientation of the facet surfaces 9 are determined, for example, as follows:

First, it is determined what is to be generated by the optical element 6 for a radiation characteristic. For example, the known radiation characteristic for a

Taillight function are generated. This results in the total distribution of the emission angle ß to be generated of the individual facet surfaces 9. Since in the present

Embodiment, the light rays parallel to the light input surface 7 and the

This results in the distribution of the angles α for the alignment of the facet surfaces 9. It is assumed that the distance I in the z-direction of the edges 1 1 is always the same, that is, a projection of the facet surfaces 9 on the

Light input surface 7 is the same size for all facet surfaces 9. The length I is in particular greater than the average thickness d of the optical element 6. The average thickness d is, for example, 3 mm. The angle α of a certain facet surface is now obtained from the distances a of the edges 1 1 to the average thickness d of the optical element 6, d. H. to the level 10.

As shown in Fig. 2, for example, the facet surface 9-1 is started. The edge 1 1-0 at the beginning of this facet surface 9-1 is at a distance of the average thickness d of the

Arranged light input surface 7, ie a is zero in this case. The next edge 1 1-1 to the adjacent facet face 9-2 is arranged at a distance of a-1 from the plane 10 at the mean thickness d of the optical element 6. This results in an angle α-ι for the alignment of the facet surface 9-1. The edge 1 1 -2 of the facet surface 9-2 to the next facet surface 9-3 is arranged at a distance a-2 from the plane 10. The value of the distance a-2 is negative since the edge 1 1-2 is arranged on the side of the plane 10 facing the light-incoupling surface 7. The distance values a for the individual facet surfaces 9 are determined as follows:

First, a maximum distance M from the plane 10 at the mean thickness d of the optical element 6 is set. This maximum distance M is smaller than the thickness d of the

Optics element 6. Now, one after the other for the facet surfaces 9-i (i = 1, n)

Random numbers P, generated. The random numbers P, are between 0 and M. For the first

Facet area 9-1, the positive value of the random number Pi is taken as the distance value a-1. At the next facet area 9-2, the negative value of the random number P _{2 is taken} as the distance value a-2. In turn, the next facet surface 9-3 again the positive value P _{3 is taken} as the distance value a-3. For consecutive facet surfaces 9, the positive and negative values of the successive random numbers P are thus alternately taken as the distance value a of the respective facet surface 9. The edges 11 of the facet surfaces 9 are now arranged at the respective distance values a, so that the zigzag pattern shown in FIGS. 2 and 3 results. Since the angular orientation of the facet faces 9 has been generated by means of random numbers, a non-repeating random pattern with regard to the alignment of the facet faces 9 is very likely to result.

When selecting the random numbers P to generate the distance values a

Advantageously still taken into account that the deviation from the random number P of the previous distance value a a defined percentage of 10% is not exceeded.

In addition, for the distribution of the total generated by the facet surfaces 9

Beam angles ß to be generated radiation characteristic of the vehicle lamp. 1

considered. This additional constraint can be taken into account in the selection of the random numbers P.

As a starting point for the determination of the angles α of the facet surfaces 9, furthermore, a cushion optic known per se can be used. The pillow-shaped bulges of this cushion optics are comparable to lenses, which is an incident parallel light beam fan out. If the same radiating characteristic as with the known cushion optics to be generated with the optical element 6, the individual pillow-shaped

Bulges on a plurality of planar individual facet surfaces 9, each with an angle α randomly divided. The weighting or distribution of the angle α corresponds to the

Distribution of the angles of a single lens, which is formed by a pillow-shaped bulge of the cushion optics. The overall radiation characteristic thus corresponds to that of the cushion optics, but this is produced by the facet surfaces 9 arranged in a non-repeating pattern. In this way, there is no substantially uniformly illuminated surface, but with slight deviations of the viewing position

Glitter effect.

LIST OF REFERENCE NUMBERS

vehicle light

casing

light source

reflector

Light lens

optical element

light injection

outcoupling

facets

-1 facet area

-2 facet surface

-3 facet area

0 level

1 edges

1-1 edge

1-2 edge

1-3 edge

1-4 edge

2 subarea

Claims

claims

1. optical element (6) for a vehicle lamp (1) with

- A light input surface (7) for coupling the light emission of a light source (3) of the vehicle lamp (1) and

- A coupling-out structure (8), wherein the directions of the coupled

Light beams (L1, L2) are changed so that a radiation characteristic is generated, which differs from the emission characteristics of the light emission of the light source (3) of the vehicle lamp (1),

characterized in that

- The coupling-out structure (8) comprises a plurality of facet surfaces (9), in which light beams (L1, L2) are coupled in an emission angle (ß), which depends on the respective angular orientation (a) of the facet surface (9), and

- The facet surfaces (9) in a portion (12) of the coupling-out structure (8) in

different angles (a) are arranged to each other in a non-repeating pattern.

2. optical element (6) according to claim 1, wherein the portion (12) at least 30% of

Auskoppelstruktur (8) makes.

3. optical element (6) according to any one of the preceding claims, wherein the partial region (12) makes up at least 70% of the coupling-out structure (8).

4. optical element (6) according to any one of the preceding claims, wherein the partial region (12) of the entire coupling-out structure (8) corresponds.

5. optical element (6) according to one of the preceding claims,

characterized,

the distribution of the emission angles (β) generated by the individual facet surfaces (9) is determined by the emission characteristic to be generated, but the angular orientations (a) of the individual facet surfaces (9) are randomly arranged relative to one another.

6. optical element (6) according to one of the preceding claims, characterized,

the facet surfaces (9) are planar and are connected to one another by edges (1 1).

7. optical element (6) according to claim 6,

characterized,

that the radius of curvature of the edges (1 1) is less than 4 mm.

8. optical element (6) according to claim 6 or 8,

characterized,

that the edges (1 1) are aligned parallel to each other.

9. optical element (6) according to one of claims 6 to 8,

characterized,

in that the length of the facet surfaces (9) between the edges (1 1) to adjacent facet surfaces (9) is greater than the thickness (d) of the optical element (6).

10. optical element (6) according to any one of claims 6 to 9,

characterized,

in that the distance (I) of the edges (1 1) of the facet surfaces (9) in a direction (z) perpendicular to the thickness (d) of the optical element (6) is always the same.

1 1. Optical element (6) according to one of claims 6 to 10,

characterized,

in that the distance a of the edges (1 1) of the facet surfaces (9) from an average of the position of the edges (1 1) in the direction of the thickness (d) of the optical element (6) is determined as follows:

a maximum distance M from the mean is determined

random numbers P between 0 and M are generated for consecutive facet surfaces (9),

for successive facet areas (9), the positive and negative values of the consecutive random numbers P are alternately taken as the distance value a of the respective facet area (9) and

the edges (1 1) of the facet surfaces (9) are arranged at the respective distance values a.

12. optical element (6) according to claim 1 1,

characterized,

that only such random numbers P are used to generate the distance value a, for which the deviation from the random number p of the preceding distance value a does not exceed a defined percentage.

13. vehicle lamp (1) with an optical element (6) according to one of the preceding

Claims.