DE19728354C2 - Refractor element as an attachment for a light source and use of such a refractor element as an attachment for a brake light of a vehicle - Google Patents

Description

The invention relates to a refractor element as an attachment for a light source, especially for a light emitting diode, with egg nem surrounding the optical axis of the refractor element neren lens area for radiated in from the light source light rays and with an inner lens area ring-shaped outer reflector area for outer Light rays from the light source.

Such a refractor element is e.g. B. by the DE 195 42 416 A1 has become known.

To the radiation distribution of the abge by a light emitting diode Luminous or reflective light can be changed be used. So in the beam path in front of the LED z. B. a Fresnel lens is provided be that of the light emitting diode in a certain Solid angle emitted light in a smaller solid angle and in particular parallel to the optical axis of the lens directs. With such a Fresnel optic, that appears the light emitted by the punctiform light-emitting diode is more flat, however, due to the limited extent of a Fresnel Fresnel lens does not cover the entire solid angle light emitted by the light-emitting diode is detected and corresponds can be distracted accordingly. Not covered by this Undesired stray light effects can occur that light e.g. B. unbe used in the automotive field of lights  things to avoid. In contrast, one of one Reflector surrounding light emitting diode only to the rear and laterally emitted light are reflected accordingly, while the light emitted forward from the reflector still unaffected under a relatively large Solid angle emerges to the front.

One in the rear window or in the rear outside area Motor vehicle provided as an additional brake light The center brake light are several light-emitting diodes next to each other, preferably in a row, to produce a flat Luminous image arranged, because of who is getting bigger the brightness of light emitting diodes for a specific Luminosity of the center brake light is less and less ode and are required at ever greater intervals. At larger distances between adjacent in the brake light arranged light emitting diodes are the individual light emitting diodes from the viewer, however, as point light sources know, so that overall there is no coherent light picture or band results.

The refractor element known from DE 195 42 416 A1 arranged upstream of a light-emitting diode to make it effective towards the front Increase light intensity. The refractor element points to this an inner lens lens designed as a Fresnel lens rich and an outer refle surrounding this ring xions range. The outer reflection area is light-in stepped on the exit side and / or light exit side to all light rays entering the refractor element center. The refractor element is with respect to his telachse (optical axis) rotationally symmetrical and has a circular effective on the light exit side Cross section on. Due to this rotational symmetry of the Re  fractor element can be on its entire circular shape tread surface by appropriate ring steps an ideal almost homogeneous luminous area can be achieved. With not rotationally symmetrical exit surface, e.g. B. in a qua dratic or rectangular exit cross-section, can, however, with the known refractor element homogeneous light distribution over the entire exit surface be achieved because the light distribution on the outer edge of the Refractor element in the corners of its exit surface each is less than in between. Especially with immediate juxtaposed refractor elements would these different light intensities in the corners make it more noticeable.

Furthermore, DE-PS 930 593 is rotationally symmetrical known resolution for a light source that is a light bundle by internal or total reflection from one to the other light coming from its longitudinal axis rays generated. For this purpose, the intent is made up of a number of separate elements composed in such a way that on each other other bounding areas of the elements an interior or total reflection of the light rays takes place.

It is therefore an object of the present invention to provide a re fracture element of the type mentioned in white ter educate that even with non-rotationally symmetrical Aus tread area essentially over this exit area homogeneous light intensity can be achieved.

This object is achieved in that the Refractor element on the light exit side a non-rotating symmetrical, preferably a rectangular or quadra tables, effective cross-section and in individual win  kel sectors is divided with respect to the optical axis, where all axial cross sections within an angular sector are essentially the same, and that the axial cross sections of two angular sectors, bezo gen to a front focus of the refractor distinguish a compression or stretching factor that according to the ratio of the largest radial Er extension of the refractor element in the two angular sectors is selected.

With this refractor element only those close to its opti inner light rays running across the axis Lens section to a z. B. as a parallel light from the Deflected light beam emerging from lens. The outer light on the other hand, rays are emitted within the reflection range by reflection z. B. also too parallel from the Refrak light rays emerging deflected. Through this Combination of refraction in the inner lens area and reflect xion in the outer reflector area, the dimensions of the Refractor element can be kept relatively low, and can compared to a lens or a reflector each captured more light and the point-shaped light emitting diode mapped on the step side as a large lighting effect become.

Since with a rotationally symmetrical in front of the optical axis block cross-section, all axial cross-sections are identical then also the luminous intensity emitted by the attachment only a function of the radius (i.e. the distance to the optical Axis), d. that is, the light distribution of a rotationally symmetrical is on a circle around the optical axis equal. With a non-rotationally symmetrical exit surface, e.g. B. with a square or rectangular exit surface  chenquerschnitt, the would without compression or extension Light distribution on the outer edge of the header in the corners of the Exit area should be smaller than in between. In particular especially in the case of attachments arranged directly next to each other there would be different light intensities in the corners make it all the more noticeable. With the invention The refractor element can otherwise be in its corner area Luminous intensity loss occurring is reduced and ideal be prevented entirely. So z. B. a punctiform LED on the square exit surface of the Re fractor elements with almost the same light intensity everywhere are mapped, d. that is, ideally there is one almost homogeneous luminous area.

In a particularly preferred embodiment of the inven the outer reflector area closes immediately to the inner lens area, the imaginary light beam, which both in the inner lens area and in the outer reflector area enters, the two areas separates and the geometric relationships of the two areas determined each other.

So that all inner rays of light from the light source are possible lightest possible scattering angles or as parallel as possible to the op table axis emerge from the refractor element is the inner lens area in preferred embodiments of the Invention designed as a converging lens. The inner Lens area z. B. have a concave lens surface.

In another advantageous development of this embodiment The shape of the inner lens area is Fresnel's Stu lens formed, in which the otherwise large thickness egg ner converging lens through a step-like structure of the lens  is reduced. The radii of curvature of the individual zone ranges surfaces of the Fresnel lens are different and so ge selects that the focal points of all zones coincide.

In particularly preferred embodiments of the invention is an open feed opening in front of the light source provided the inner lens area, over the inner circumference the outer rays of the light source in the outer outer reflector area can be fed. This interior Front wall is preferably a coaxial to the optical Axial cylinder surface. According to the refractive index len of the refractor element and the medium surrounding it, e.g. B. air, the light turns on entering the interior breaking wall to or away from the optical axis. Such a feed opening allows the detection of one large solid angle of the emitted light, and in particular the light source can also be inside the feed opening be arranged, which is also part of a Light source can detect light emitted to the rear.

To reflect the outer rays of light within the outer gate area forward, as parallel as possible to the optical To align axis is at a particularly preferred off leadership form of the invention to the one in the outer Re outer light rays fed into the reflector area after ne reflecting outer peripheral surface of the refractor element intended.

This embodiment can be an advantageous further development form the outer peripheral surface of the outer reflector rich with respect to the optical axis of the refractor element at least in sections parabolic or straight line elements existing. This geometry has the  essential advantage that all of the outer peripheral surface back reflected outer rays parallel to the optical Axis are deflected and as a parallel light from the re fracture element can emerge.

In order in particular in the case of refractories produced in the injection molding process Plastic gate elements one while cooling the Injection molded part shrinkage and resulting The refractor demonstrates how to avoid surface deformation element a center located on the light exit side le opening.

Through a coaxial located in the inner lens area central cylinder of the Refrak running to the optical axis The manufacture of the refractor element can be achieved with gate elements simplify considerably in the spraying process. The through the Beams of light extending from the central cylinder Light source emitted almost parallel to the optical axis will not be affected.

The invention also relates to the use of a refractor elements as an attachment for several, preferably in a row hey, light sources arranged next to each other, preferably LEDs, a brake light, in particular brake means light, of a vehicle as described above.

This use makes it possible to use an optical light strip essentially on its luminous surface for the viewer to train the same light intensity. The light emission effective cross-sections of several refractor elements preferably complement each other to a full area Overall cross section without gaps in between. Prefers  is the effective cross section ei on the light exit side Nes rectangular or square refractor element.

Further advantages of the invention result from the Be writing and drawing. Likewise, the above mentioned and invented the features further invented according to each individually or in groups any combination can be used. The shown and described embodiments are not intended to be exhaustive to understand the eating list, but rather have playful character for the description of the invention.

The invention is illustrated in the drawing and is hand explained in more detail by two embodiments. It shows:

Fig. 1 in a simplified longitudinal section according to II in Fig. 3 shows a first embodiment of an inventive refractor element with an inner lens section designed as Sam lens and with a schematically indicated beam path through the refractor element;

FIG. 2 shows a perspective view obliquely from above onto the light entry side of the refractor element according to FIG. 1;

Fig. 3 is a plan view of the light entrance side of the Refraktorelements of FIG. 1;

Fig. 4 in a simplified longitudinal section according to IV-IV in Fig. 6 shows a second embodiment of a refractor element according to the invention with an inner lens portion formed as Fres nel step lens and with a schematically indicated beam path through the refractor element;

Fig. 5 is a perspective view obliquely from above on the light entry side of the Refraktorelements of FIG. 4;

FIG. 6 shows a plan view of the light entry side of the refractor element according to FIG. 4;

FIG. 7 shows a plan view of the light exit side of the refractor element according to FIG. 4; and

Fig. 8 is a longitudinal section according to VIII-VIII in Fig. 6, the refractor element according to Fig. 4.

The figures of the drawing show the Ge according to the invention The subject is partly highly schematic and is not necessary understandable to scale.

In Figs. 1 to 3 is a first embodiment of ei nes Refraktorelements 10, a light emitting diode (LED) 12 is arranged in its front focal point 11 is shown. The Re fraktorelement 10 serves to emit the light rays emitted from the point-shaped light emitting diode 12 to the front over a large area, and can z. B. be made of acrylic glass, in particular polymethyl methacrylate (PMMA), injection molded part.

For this purpose, the refractor element 10 has its optical axis 13 surrounding inner lens area 14 for the light emitted by the light-emitting diode 12 in an inner solid angle in nere light rays 15 and a region 14 surrounding this inner lens area surrounding the outer reflector area 16 for the outer light rays 17 . The outer reflector area 16 adjoins the inner lens area 14 directly.

On the light entry side of the refractor element 10 , in front of the inner lens region 14 there is provided at the front end a feed opening 18 which is open towards the front focal point 11 and whose bottom is formed as a converging lens with a concave surface 19 . The light rays emitted by the light-emitting diode 12 and incident on this concave surface 19 are the inner light rays 15 , which are refracted further to the optical axis 13 in accordance with the concave surface 18 and then emerge from the front of the refractor element 10 .

The outer light rays 17 , which do not strike the concave surface 19 , enter laterally via the cylindrical inner peripheral wall 20 centered on the optical axis 13 into the outer lens region 16 . They are deflected away from the optical axis 13 on the inner circumferential wall 20 in accordance with the refraction ratio of air to the material of the refractor element 10 and hit the outer circumferential surface 21 of the refractor element 10 , which the outer light beams 17 in the direction of an end exit from the Front 10 reflected. The contour of the outer circumferential surface 21 can either be chosen so that the outer light rays 17 impinging on it are reflected due to total reflection, or the outer circumferential surface 21 can be mirrored from the outside.

In the exemplary embodiment according to FIG. 1, the outer contour of the outer peripheral surface 21 is chosen to be parabolic in such a way that all outer light rays 17 incident over the inner peripheral wall 20 in the outer Reflexionsbe 16 emerge as parallel as possible to the optical axis 13 from the refractor element 10 .

Through a light exit side provided central opening 22 in the refractor element 10 and through the feed opening 18 , the refractor element 10 has only small wall thicknesses, so that compared to a massive Ausfüh approximate shape, the shrinkage occurring during the spraying process are significantly less. From the concave surface 19 of the inner lens region 14 there is a center cylinder 23 directed towards the front focal point 11 , which facilitates the manufacture of the refractor element 10 in the spraying process and does not impair the beam path of the inner light rays 15 .

Figs. 2 and 3 show the light entry side of the Refrak door element 10, which may be attached via dovetail-shaped projections 24. The cross section of the refractor element 10 is divided into individual angular sections (angular sectors 25 ), the axial cross sections of all axial sections within an angular sector 25 being identical. Since the ra diale extension of the individual angle sectors 25 - in contrast to a circular light exit cross section - in the exemplary embodiment rectangular light exit cross section of the attachment 10 is different, the diagonally running angle sectors 25 b are compared to the intermediate angle sectors 25 a except for one Scaling with respect to the front focus 11 of the intent 10 equal to each other. In other words, the axial cross sections of two angle sectors differ with respect to a front focal point of the refractor element by a compression or stretching factor which is selected in accordance with the ratio of the largest radial extension of the refractor element in the two angle sectors. This congestion or extension of the individual angle sectors 25 ensures that light is also deflected into the corner regions of the refractor element 10 and also exits there.

In the example shown in Figs. 4 to 8 of a second execution example Refraktorelements 10 'are the refractor element 10 of the first embodiment funktionsmä SSIG corresponding parts carry the suffix' marked in records.

Fig. 4 shows parts not lying behind the cutting plane; these are shown in Fig. 8.

In the refractor element 10 ', the inner light beams 15 ' emitted by the light-emitting diode 12 strike the inner lens region 14 ', which is designed as a Frenel step lens with steps 18 '. For reasons of injection technology, the central cylinder 23 'extends on both sides of the inner lens region 14 '. In the illustrated embodiment, the outer peripheral surface 21 'is composed of two straight pieces, the outer peripheral surface being able to be formed by pieces or by a combination of parabola and straight pieces.

From the example shown in Fig. 4 the beam path is to erse hen that the internal light rays' are out Gebro surfaces and then through the stages 18 '15' as it enters the inner lens portion 14 'to the optical axis 13 rule parallel to the optical axis 13' get distracted. The dimensions of the Fresnel Fresnel lens and the thickness of the inner reflector region 14 'are chosen such that even the outermost of the inner light rays 15 ' after passing through the inner lens region 14 'is deflected in parallel by the outermost of the steps 18 '. With this refractor element 10 ', according to the beam path according to FIG. 4, the entire light emitted from the front of a light-emitting diode 12 can be deflected over a large area to par allelic light.

The views according to FIGS. 5 to 7 show that the refractor element 10 'is also divided in cross-section into individual sectors 25 ' with respect to the optical axis 13 '. The axial cross sections within a sector 25 'are each identical, while the axial cross sections of two sectors are identical to one another except for a scaling with respect to the front focal point 11 ' of the refractor element 10 '. The scaling is selected for each sector 25 'in such a way that the light fed in also emerges from the corner regions of the front light exit surface of the refractor element 10 '. Since the scaling with respect to the front focal point 11 'follows, the stages 18 ' of the respective sectors 25 'of the Fresnel lens are offset from one another in the direction of the optical axis 13 ' ( FIG. 8). The top row of steps in FIG. 8 runs in the direction of the diagonals of the light exit surface of the refractor element 10 '.

Claims (10)

1. refractor element ( 10 ; 10 ') as an attachment for a light source, in particular for a light-emitting diode ( 12 '; 12 ') with an inner lens area surrounding the optical axis ( 13 ; 13 ') of the refractor element ( 10 ; 10 ') ( 14 ; 14 ') for inner light rays emitted by the light source ( 15 ; 15 ') and with an outer reflector region surrounding the inner lens region ( 14 ; 14 ') in an annular manner ( 16 ; 16 ') for outer light rays ( 17 ; 17th ') the light source, characterized in that
that the refractor element ( 10 ; 10 ') on the light exit side has a non-rotationally symmetrical, preferably rectangular or square, effective cross section and in individual angular sectors ( 25 , 25 a, 25 b; 25 ', 25 a ', 25 b') with respect to the optical axis ( 13 ; 13 ') is subdivided, with all axial cross sections within an angular sector ( 25 , 25 a, 25 b; 25 ', 25 a ', 25 b') being essentially the same, and
that the axial cross sections of two angular sectors ( 25 , 25 a, 25 b; 25 ', 25 a', 25 b ') refer to one in front of their focal point ( 11 ; 11 ') of the refractor element ( 10 ; 10 ') Distortion or stretching factor differ, which is selected according to the ratio of the greatest radial extension of the refractor element ( 10 ; 10 ') in the two angular sectors ( 25 , 25 a, 25 b; 25 ', 25 a ', 25 b') . 2. Refractor element according to claim 1, characterized in that the outer reflector region ( 16 ; 16 ') un indirectly to the inner lens region ( 14 ; 14 ') closes. 3. Refractor element according to claim 1 or 2, characterized in that the inner lens region ( 14 ; 14 ') is designed as a converging lens. 4. Refractor element according to claim 3, characterized in that the inner lens region ( 14 ') is designed as a Fresnel lens. 5. Refractor element according to one of the preceding claims, characterized by a feed opening ( 18 ; 18 ') open to the light source in front of the inner lens area ( 14 ; 14 '), via the inner peripheral wall ( 20 ; 20 ') of the outer rays ( 17 ; 17 ') of the light source in the outer reflector area ( 16 ; 16 ') are fed. 6. Refractor element according to one of the preceding claims, characterized by an external light which is fed into the outer reflector region ( 16 ; 16 ') ( 17 ; 17 ') and which reflects the outer peripheral surface ( 21 ; 21 ') of the refractor element ( 10 ; 10 '). 7. refractor element according to claim 6, characterized in that the outer peripheral surface ( 21 ; 21 ') of the outer reflector region ( 16 ; 16 ') with respect to the optical axis ( 13 ; 13 ') of the refractor element ( 10 ; 10 ') at least in sections parabolic or consisting of straight segments is formed. 8. Refractor element according to one of the preceding claims, characterized by a central opening ( 22 ; 22 ') located on the light exit side in the refractor element ( 10 ; 10 '). 9. Refractor element according to one of the preceding claims, characterized by an inner lens area ( 14 ; 14 ') located coaxially to the optical axis ( 13 ; 13 ') extending central cylinder ( 23 ; 23 '). 10. Use of a refractor element ( 10 ; 10 ') according to one of the preceding claims, as an attachment for several, preferably in a row, side by side light sources, preferably light emitting diodes ( 12 ; 12 '), a brake light, in particular brake light, a vehicle.