AT514573A4 - Light-guiding device and lighting unit with such a light-guiding device - Google Patents

Abstract

The invention relates to a device (1) for directing the light beams of a plurality of light sources (2) in at least one predetermined direction, comprising a flat optical element (3) of transparent material having an axis of symmetry (4), which optical element (3) has a light entrance side (5) with a substantially parabolic profile and a light exit side (6), wherein the light entrance side (5) of the optical element (3) in a plurality of light entry surfaces (7) and behind in a direction according to the predetermined direction the light beams corresponding to the angle arranged reflecting surfaces (8) is segmented and a lighting unit (15) with such a light-guiding device (1). According to the invention, each light entry surface (7) in the direction of the symmetry axis or plane (4) opposite edge (9) of the optical element, on which edge (9) the locations (10) for the arrangement of the light sources (2) are provided.

Description

The invention relates to a device for directing the light beams of a plurality of light sources in at least one vorbe-direction, with a flat optical element austransparentem material with a Symmetrieachse- or plane, which optical element has a light entrance side with a substantially parabolic profile and a Light exit side, wherein the light entrance side of the optical element is segmented into a plurality of light entry surfaces and behind it in a corresponding to the predetermined direction of the light beams corresponding angle arranged reflecting surfaces.

Furthermore, the invention relates to a lighting unit with ei¬ner plurality of light sources and a Lichtlenk¬ device mentioned above.

Light-guiding devices and lighting units of the present type have long been known in a variety of Ausführungsfor¬men and usually serve to direct the light rays of a or a small number of light sources in a predetermined direction. For example, Fresnel lenses focus the light of a light source in the direction of the optical axis of the lens. To collimate the light of a point light source, it is typical to use a parabolic mirror or lens. This principle can be extended from a point light source to a small group of point light sources. However, if one wishes to collimate a large number of light sources, the prior art devices are no longer applicable without re-dividing the light sources into smaller groups and providing their own collimators. With the advent of light-emitting diodes as light sources, many lighting units no longer exist today but from a large number of light sources whose light beams can not be directed in any suitable manner with conventional light-guiding devices.

DE 10 2010 028 755 A1 describes an optical lens element which is suitable in principle only for a light source or an array of light sources arranged at one location.

DE 10 2011 118 456 A1 also describes an optical component for illumination purposes, which is intended only for a single light source.

From US Pat. No. 8,235,556 B2, an optical element for collimating the light beams of many light sources has become known. However, the production effort for such an optical element is very large and increases with the number of light sources.

The object of the present invention is to provide a light-guiding device of the above type and a lighting unit with such a light-guiding device, by means of which the light beams of a plurality of light sources can be steered in suitable directions in predetermined directions. The constructive effort and the production costs for such a light guide The light-directing device or lighting unit should be as small as possible in order to enable a broad application in a wide variety of application areas. The disadvantages of the prior art should be avoided or at least reduced.

The object of the invention is achieved by an above-mentioned Lichtlenkvorrichtung in which each light entrance surface in the direction of the symmetry axis or planar opposite edge of the optical element, at which edge the locations for the arrangement of the light sources are provided, so that the light beams of the light sources substantially normal enter the light entry surfaces, reflected at the arranged behind the light entry surfaces reflection surfaces and are deflected over the light exit side in the predetermined direction. Essentially, the present invention provides an optical element capable of efficiently collimating nearly any number of light sources. The Lichtlenkvor direction is gekenn¬zeichnet by a simple and compact structure. The light sources are arranged at the edge of the optical element and transmit their light beams at a corresponding angle in the light entry surfaces of the optical element and are totally reflected at the reflection surfaces and exit via the light exit side in the desired direction. By utilizing the phenomenon of total internal reflection, the optical element or the light-guiding device or the lighting unit can be realized particularly cost-effectively.

Preferably, the light entry surfaces are formed with a circular cross section, wherein the center of the formed with kreisför¬migem cross section light entry surfaces substantially with the locations for the arrangement of the light sources coincides.

This circular or spherical design of the light-entry surfaces ensures that the light beams originating from the light sources essentially occur in a normal manner to the surface of the optical element, whereby back reflections can be minimized and refractions of the incoming light beams can be suppressed.

According to a further feature of the invention, the light exit side of the optical element is segmented into a plurality of light exit surfaces. By segmenting the light exit side of the optical element in this way, a material-saving design of the optical element and thus a more compact design can be achieved. The density and shape of the light exit surface segments is substantially arbitrary.

If the light exit surfaces are inclined to the normal axis or plane with respect to the normal, the light beams emerging from the light exit side of the optical element can be directed in desired directions. In this way, even more complex illumination patterns for specific applications without further optics and thus increased production effort can be realized.

The optical element preferably consists of optically transparent material, preferably plastic or glass, and is preferably produced by casting. As a result, the light-deflecting device or the lighting unit can be manufactured in a very cost-effective manner in large numbers, so that a wide applicability can be ensured.

If lenses are arranged on the edge of the optical element in front of the locations for the arrangement of the light sources, the directional characteristic of the light waves can be correspondingly changed.

Depending on the light sources used, it may be advantageous to change the directional characteristic of the same by means of such lenses or to adapt them to the optical element of the light-guiding device. Often it will be less expensive to provide such lenses in front of standard light sources instead of using more expensive light sources with a specific directional characteristic. In the subject light-guiding device, optimum characteristics have been obtained when the light sources have flat or elliptical directivity. As a result, scattered light can be avoided or at least reduced. Insofar as the light sources do not have such an elliptical or flat directional characteristic, an improvement by the lenses ahead of the light sources can be achieved.

The optical element and the lenses can also be produced in one piece, as a result of which the manufacturing costs and the installation or assembly costs can be further reduced.

In order to achieve different lighting effects, the optical element and / or the lenses may be colored. When plastic or glass is used for the optical element and / or the lenses, such coloring can take place in the same way as the production process of the optical element. Alternatively, staining may also be achieved by applying color layers.

An antireflection coating can be arranged on the light entry surfaces of the optical element, on the light exit surfaces of the optical element and / or on the lenses, whereby reflection losses can be suppressed.

Preferably, the optical element is symmetrical, in particular rotationally symmetric, formed around the axis of symmetry or plane. With such a symmetrical, in particular rotationally symmetrical design, of the optical element of the light-guiding device, substantially any number of light sources can be arranged along the edges of the optical element or along its circumference and their light beams can be directed in the desired direction on the light exit side of the optical element.

The object according to the invention is also achieved by an above-mentioned lighting unit having a multiplicity of light sources and an above light-guiding device, the light sources being arranged at least at a part of the edge of the optical element lying opposite the axis of symmetry or plane. Such a lighting unit is characterized by a particularly compact and compact low-cost construction and high flexibility in the luminous patterns to be achieved. With respect to further advantages, reference is made to the above description of the Lichtleit¬elements.

The light sources preferably have narrow directivity. As already mentioned above, with respect to an optimal function of the optical element or the total reflections occurring therein, it is advantageous if the light sources have a narrow directional characteristic.

Furthermore, it is advantageous if the light sources have elliptical directional characteristics. By such an elliptic directivity, stray light can be effectively suppressed.

Preferably, the light sources are formed by light-emitting diodes. Light-emitting diodes are currently available in different colors and with different power densities in a particularly cost-effective manner and moreover have an especially small overall size. Even if the luminous efficiency in the case of light-emitting diodes is relatively low, it may be necessary for light-emitting diodes with a higher light output to cool the light sources. However, since the light sources of both subject lighting units are located at the edge of the optical element, dissipation of the waste heat can be done relatively easily. Another advantage is given da¬durch that light emitting diodes with elliptical Richtcharakte¬ristik are relatively inexpensive available.

Alternatively, the light sources may also be formed by laser diodes. Compared to LEDs, laser diodes have the advantage that they have a particularly narrow directional characteristic, whereby stray light can be prevented.

If lenses are arranged in front of the light sources, the directional characteristic of the light sources can be correspondingly changed. As already mentioned above, the desired narrow directional characteristics of the light sources can be produced or improved by the lenses. Such lenses may also be made integral with the optical element.

Preferably, the light sources are designed to emit white light. For most applications, white light is required. Since low-cost light-emitting diodes in the white spectral range are already available, cost-effective lighting units for emitting white light can thus also be produced. For various lighting effects and applications, the light sources may also be designed to emit colored light. Such colored light sources can be used for certain applications, e.g. Tail lights of vehicles, turn signals of vehicles, traffic lights or stage lighting body, be necessary.

A cover element made of at least partially transparent material can be arranged in front of the light exit side of the optical element. With such a cover, pictograms or the like can be provided in the illumination unit in a template-like manner, as they are advantageous or desirable for many applications. For example, in such a cover element, pictograms of standing or walking people of transparent material may be arranged, as is common in pedestrian traffic lights.

To protect the lighting unit, especially in outdoor applications, it is advantageous if a preferably water-tight housing is provided.

The present invention will be explained in more detail with reference to the attached Zeichnun¬gen. Show in it

Fig. 1 is a plan view of a circular device for

Directing the light beams of a plurality of light source velocities to light sources;

Figure 2 is a section through the circular light-guiding device according to Figure 1 along the section line II - II.

3 is a detail view of a part of a Lichtlenkvorrich- device.

4 shows a section through another embodiment of a circular light-guiding device with material-saving design of the light exit side of the optical element;

Fig. 5 is a plan view of a device for steering the

Light rays of a plurality of light sources including light sources as a line array;

6 shows a sectional view through an illumination unit with an optical steering device as a line array according to FIG. 5 along the section line VI-VI;

FIGS. 7A to 7C show examples of light-deflecting devices with a changed direction of the exiting light beams; undFig. 8 is a plan view of a light-guiding device in the form of a polygon.

Fig. 1 shows a plan view of a circular device 1 for directing the light rays of a plurality of light sources 2sall light sources. The light-guiding device 1 comprises a flat, optical element 3 made of transparent material with an axis of symmetry or plane 4. In the example shown, the optical element 3 is arranged rotationally symmetrical about the axis of symmetry 4. At the edge 9 of the optical element 3, the light sources 2, which are formed, for example, by light-emitting diodes, are arranged such that the light beams of the light sources 2 radiate in the direction of the axis of symmetry 4. As better seen in the sectional image through the optical element 3 according to FIG. 2, the optical element 3 has a light entrance side 5 and a light exit side 6. The light entry side 5 is segmented into a multiplicity of light entry surfaces 7 and, behind them, adjoining reflection surfaces 8. In the illustrated example, the light exit side 6 of the optical element 3 is formed in a planar and non-segmented manner. The Lichteintrittsflä¬ Chen 7 are preferably circular or spherical, wherein the center 11 of the circles of the light entry surfaces 7 substantially coincides with the locations 10 for the arrangement of the light sources 2. This ensures that the light beams emitted by the light sources 2 essentially enter the light entry surfaces 7 in the normal manner and that no losses occur due to partial reflections. A total reflection of the light rays in the direction of the light exit side 6 takes place at the reflection surfaces 8 arranged behind the light entry surfaces 7. In the illustrated embodiment of the light-guiding device 1, all the light rays of all the light sources 2 are aligned substantially parallel to each other and normal to the light exit side 6 of the optical element 3. Such a light-guiding device 1 can be manufactured relatively easily and inexpensively. The calculation of the radii of the circular or spherical light entry surfaces 7 and the inclination of the reflection surfaces 8 and the number of segments must be adapted to the respective number of light sources 2 and the size of the optical element 3, which are made relatively quickly and easily by various mathematical models and calculation programs can.

3, some light entry surfaces 7 and reflection surfaces 8 of the optical element 3 are shown, and the respective radius for the circular or spherical design of the light entry surfaces 7 is plotted from the detail view of a part of the light guide device 1according to FIG. The light entrance surface 7 on the right side of FIG. 3 accordingly has a circular area of radius R 1 from the center 11, which coincides with the locations 10 for the arrangement of the light sources 2. The radius R2 for the next light entrance surface 7 is smaller corresponding to the distance from the previous light entry surface 7. After the number of segments of the light entry surface 7 of the optical element 3 has been determined, the respective radii and inclinations of the reflection surfaces 8 can be easily calculated by software. Finally, the optical element 3 can be produced simply and quickly by milling from a plastic or glass block or by producing a corresponding negative mold and then casting it with plastic or glass.

Fig. 4 shows a section through another embodiment of a circular light-guiding device 1 with material-saving design of the light exit side 6 of the optical element 3.Dabei the light exit side 6 of the optical element 3 as the light entrance side 5 is segmented into a plurality of light exit surfaces 12, which light exit surfaces 12 all flat and substantially are arranged normal to the symmetry axis or plane 4 angeord¬net. As will be explained below with reference to FIGS. 7A to 7C, a change in the illumination pattern can be achieved by inclined arrangement of the light exit surfaces 12.

Figs. 5 and 6 show a plan view and a section through a device 1 for directing the light beams of a plurality of light sources 2 together with light sources 2 as a line array. The light sources 2 are arranged on both edges 9 of the symmetrically arranged optical element 3. In this way, any lengths of light-guiding devices 1 or lighting units 15 can be produced, which can also have any desired sequence (see Fig. 8). Theoretically, an asymmetrical structure of the light guide device 1 is also conceivable by omitting a side of the optical element 3 adjacent to the plane of symmetry 4. As can be seen from the sectional view of FIG. 6, the optical element 3 can also be surrounded by a housing 17 and an at least partially transparent cover element 16, by means of which use of the illumination unit 15 also in the exterior area is made possible. To change the light characteristic of the light sources 2, two lenses 14 can be arranged in front of the light sources, which lenses can also be produced in one piece with the optical element 3.

FIGS. 7A to 7C show examples of light-deflecting devices 1 with a changed direction of the emerging light beams. FIGS. 7A to 7C show variants of the light-directing device 1 or illumination unit 15, wherein a change in the direction of the light rays emerging can be achieved by tilting the light exit surfaces 12. In the variant according to FIG. 7A, the light exit surfaces 12 have been tilted with respect to the normal to the symmetry axis or plane 4 of the optical element 3, whereby the light rays emerging from the optical element 3 point outward away from the symmetry axis or plane 4. In the variant according to FIG. 7B, all the light exit surfaces 12 are arranged substantially normal to the axis of symmetry or plane 4 and all the light beams are arranged parallel in the direction of the symmetry axis or plane 4. In the variant according to FIG. 7C, the light exit surfaces 12 of the optical element 3 are arranged inclined in the direction of the symmetry axis or plane 4, whereby the light beams are directed in the direction of the symmetry axis or plane 4. By different inclination of the light exit surfaces 12 of the optical element 3, various light patterns and light effects can be obtained.

Finally, Fig. 8 shows a plan view of a Lichtlenkvor¬richtung 1 in the form of a polygon. As already mentioned above, the optical element 3 of the light-guiding device 1 can be symmetrically arranged to form a symmetry plane 4 running along a polygon. In this way, illumination units 15 can be produced to achieve individual illumination patterns. This opens up new possibilities in lighting technology.

The present invention increases the design possibilities in lighting technology for simple lighting applications, such as the replacement of existing fluorescent tubes with LED linear arrays or also adapted housing or Arbeits¬ illuminations. Also in the automotive industry, where high luminous densities are required with low energy consumption and high reliability, such lighting units can be used. By using a plurality of Lichtquel¬len higher reliability of the lighting unit is guaranteed, since the failure of individual light sources on the function of the lighting unit has no or only a negligible influence.

Claims (20)

Claims 1. A device (1) for directing the light beams of a plurality of light sources (2) in at least one predetermined direction, comprising a flat optical element (3) made of transparent material with a plane of symmetry (4), which optical element 3) has a light entrance side (5) with a substantially parabolic profile and a light exit side (6), wherein the light entry side (5) of the optical element (3) into a plurality of light entry surfaces (7) and behind it in a direction according to the predetermined Segmented light beams corresponding angle angles reflecting surfaces (8), characterized in that each light entrance surface (7) in the direction of the symmetry axis or even (4) opposite edge (9) of the optical element (3), at which edge (9) the locations (10) for the arrangement of the light sources (2) are provided so that the light beams of the light sources (2) is substantially normal in di e light entry surfaces (7) eintre-th, reflected at the behind the light entry surfaces (7) arranged reflecting surfaces (8) and are directed over the Lichtaustritts¬seite (6) in the predetermined direction. 2. Light guide device (1) according to claim 1, characterized gekenn¬zeichnet that the light entry surfaces (7) are formed with a circular cross-section, wherein the center (11) of the mitkreisförmigem cross-section formed light entry surfaces (7) substantially with the locations (10) for the Arrangement of the light sources (2) matches. 3. light guide device (1) according to claim 1 or 2, characterized ge indicates that the light exit side (6) of the optical element (3) is segmented into a plurality of light exit surfaces (12). 4. light guide device (1) according to claim 3, characterized gekenn¬zeichnet that the light exit surfaces (12) relative to the Nor¬malen on the Symmetrieachse- or plane (4) are inclined. 5. Light-guiding device (1) according to one of claims 1 to 4, characterized in that the optical element (3) consists of op¬ table transparent material, preferably plastic or glass, and is preferably made by casting. 6. light guide device (1) according to one of claims 1 to 5, characterized in that at the edge (9) of the optical element (3) in front of the points (10) for the arrangement of the light sources (2) lenses (14) for changing the Directional characteristic of Lichtquel¬len (2) are arranged. 7. Light-guiding device (1) according to claim 6, characterized gekenn¬zeichnet that the optical element (3) and the lenses (14) are manufactured einteilteilig. 8. light-guiding device (1) according to claim 6 or 7, characterized ge indicates that the optical element (3) and or or the lenses (14) are formed colored. 9. light guide device (1) according to one of claims 1 to 8, characterized in that on the light entry surfaces (7) of the optical element (3), on the light exit surfaces (12) of the optical element (3) and or or on the lenses (14) an antireflection coating (13) is arranged. 10. Lichtlenkvorrichtung (1) according to one of claims 1 to 9, characterized in that the optical element (3) symme¬trisch, in particular rotationally symmetrical to the Symmetrieach¬se- or flat (4) is formed. 11. lighting unit (15) having a plurality of light sources (2) and a device (1) for directing the light beams of the light sources (2) according to one of claims 1 to 10, characterized ge indicates that the light sources (2) at least at one Part of the symmetry axis or flat (4) opposite edge (9) of the optical element (3) are arranged. 12. Lighting unit (15) according to claim 11, characterized gekenn¬zeichnet that the light sources (2) have narrow directional characteristics. 13. Lighting unit (15) according to claim 12, characterized in that the light sources (2) have elliptical Richtcharakte¬ristik. 14. Lighting unit (15) according to any one of claims 11 to 13, characterized in that the light sources (2) are formed by light-emitting diodes. 15. Lighting unit (15) according to any one of claims 11 to 13, characterized in that the light sources (2) are formed by Laserdi¬oden. 16. Lighting unit (15) according to any one of claims 11 to 15, characterized in that in front of the light sources (2) lenses (14) for varying the directional characteristic of the light sources (2) are arranged. 17. Lighting unit (15) according to any one of claims 11 to 16, characterized in that the light sources (2) are designed to emit white light. 18. Lighting unit (15) according to any one of claims 11 to 17, characterized in that the light sources (2) are designed to emit colored light. 19. Lighting unit (15) according to any one of claims 11 to 18, characterized in that in front of the light exit side (6) of the optical element (3) a cover member (16) is arranged at least partially transparent material. 20. Lighting unit (15) according to any one of claims 11 to 19, characterized in that a preferably waterproof Ge¬ housing (17) is provided.