WO2012020082A1

WO2012020082A1 - Arrangement for emitting light with light-guiding element and reflector

Info

Publication number: WO2012020082A1
Application number: PCT/EP2011/063837
Authority: WO
Inventors: Burkhard Von Kloeden
Original assignee: Zumtobel Lighting Gmbh
Priority date: 2010-08-13
Filing date: 2011-08-11
Publication date: 2012-02-16
Also published as: CN102985751A; DE102010039306A1; EP2603732B1; EP2603732A1

Abstract

An arrangement (1) for emitting light has at least one substantially punctiform light source (5), a light-guiding element (10), arranged in front of the light source (5) in the emission direction, made of a transparent material and a reflector (5) surrounding the light-guiding element (10). The light-guiding element (10) has a substantially cylindrical design, with one end face of the cylinder forming a light-entry surface (11), the side of the cylinder lying opposite the light-entry surface being at least partly angled with respect to a longitudinal axis (I) of the cylinder such that it is permeable to part of the light and reflective to another part of the light, and the lateral face (18) of the cylinder being provided with structures (19) for coupling light out.

Description

Arrangement for emitting light with light guide element and reflector

The present invention relates to an arrangement for emitting light according to the preamble of claim 1, which has at least one substantially punctiform light source, wherein the light emission by means of a light source upstream of the light-guiding element and a light-guiding element surrounding the reflector. The punctual light source used is in particular an LED.

LEDs are increasingly being used in lighting technology, as they have numerous advantages over conventional light sources such as fluorescent lamps or light bulbs. One advantage of LEDs, for example, is that they emit their light predominantly in the direction in which one

Luminaire construction should also be the actual light output, ie in the direction of the light exit. At the same time, however, there is also a disadvantage of the LEDs, since targeted influencing of the emitted light beams for directing the light is only possible by positioning specific optical elements directly in the region of the light emission of the LEDs. Due to the high direct component of the light emitted by LEDs and the low influenceability inevitably results in a certain amount of scattered light, which has a very disturbing effect, especially in narrow-beam distributions. Furthermore, in the case of LED modules in which multicolor LEDs are used (for example in the case of RGB modules), a specific color mixture is required in order ultimately to achieve homogeneous light output with a desired mixed color. Accordingly, it is an object of the present invention to provide a novel concept for influencing the light output in lighting arrangements with essentially punctiform light sources, in particular LEDs, with the aid of which the abovementioned objectives are achieved. In particular, on the one hand an effective influencing of the light output should be possible, on the other hand should be achieved in the case of using different colored light sources effective color mixing.

The object is achieved by an arrangement for emitting light, which has the features of claim 1. Advantageous developments of the invention are the subject of the dependent claims. The solution according to the invention is based on the use of a special

designed light-guiding element, with the help of an effective one

Light control is possible, on the other hand, the mixing of the light emitted by the light sources or is promoted. This special light-guiding element is designed substantially cylinder-like, wherein an end face of the cylinder forms a light entry surface. One of the light entry surface opposite side of the cylinder is then at least partially aligned with respect to a longitudinal axis of the cylinder. It is thereby permeable to one part of the light and reflective to another part of the light, in which case the reflected portion of the light over the lateral surface of the cylinder, which with structures for

Lichtauskopplung is provided, is delivered to a surrounding the light guide element reflector. This special design makes it possible to effectively use all the components of the light emitted by the light source.

According to the invention, therefore, an arrangement for emitting light is proposed, which has at least one substantially point-shaped light source, a light source in the emission direction upstream of a light-guiding element of a transparent material and a reflector surrounding the light guide, wherein

According to the invention, the light-guiding element is designed substantially cylinder-like, wherein an end face of the cylinder forms a light entry surface and the

Light inlet surface opposite side of the cylinder is at least partially inclined relative to a longitudinal axis of the cylinder so that it is transparent to a part of the light and reflective for another part of the light, and wherein the lateral surface of the cylinder is provided with structures for light extraction.

As light sources according to the invention preferably LEDs are used, which may in particular be different colored LEDs. In order to further optimize the mixture of the light emitted by the different LEDs, it is preferably provided that the light entry surface of the light-guiding element is provided with a scattering structure, in particular a microstructure. Alternatively, an optical element, for example a foil, which has a corresponding scattering structure, can also be provided in the region of the light entry surface.

in particular has a microstructure.

The arrangement according to the invention can be used both for a symmetrical and for an asymmetrical light output. In the case of a symmetrical light output, the light exit surface of the light-guiding element, that is the

Light entry surface opposite side preferably by a lateral surface a recess extending in the light guide, wherein the recess is formed, for example, conical. Depending on how

narrow beam the light output should be made, then the cone of the cone can be selected. This can be in particular in the range between 0 ° and 45 °.

As an alternative to a symmetrical light output, however, a

be provided asymmetric light output. In this case, that is the

Light incident surface opposite surface of the light-guiding element, on the one hand, a refraction of light and on the other hand takes place a reflection, preferably formed by an oblique face.

The reflector surrounding the light guide element according to the invention is preferably in the form of a pot. Again, the shape of the reflection surface can be changed in order to influence the light output in the desired manner.

Finally, the inventive arrangement makes it possible to influence the emission of light from point light sources, in particular LEDs, in a simple but effective manner. By using the different light-guiding properties of the elements, luminaires with different light emission characteristics can be achieved in a simple manner, without being distinguishable from the outside at first sight.

The invention will be explained in more detail with reference to the accompanying drawings. Show it:

Figure 1 shows a first embodiment of an inventive

Arrangement for emitting light;

FIGS. 2 to 4 are views of the light guide element used in the first embodiment;

Figure 5 is a sectional view of the light-guiding element of Figs. 2 to 4 and

Figures 6 to 8 are views of a second embodiment of a

Light guide element, with the help of an asymmetric light output is achieved. The arrangement according to the invention, generally designated by the reference numeral 1 in FIG. 1, serves to direct the light emitted by a plurality of punctiform light sources, in particular LEDs. In this case, in particular, differently colored LEDs-for example in the colors red, green and blue-are preferably used in order to achieve mixed light of almost any color location or any desired color temperature by controlling the intensities of the different colors. With the aid of the arrangement 1 according to the invention, on the one hand a particularly good mixing of the light of the different LEDs is achieved, on the other hand, the light can be effectively directed into a specific area. The arrangement 1 can be used, for example, in so-called LED emitters.

Essential elements of the arrangement 1 according to the invention are on the one hand a pot-shaped reflector 2 and on the other hand a transparent light-guiding element 10, which is arranged approximately in the region of the center of the reflector 2. The

Embodiment of the light-guiding element 10 will be detailed below

described. Both elements, ie reflector 2 and light guide element 10, are held by an annular ausgestaltetes holding element 3, via which at the same time also a fastening to or in the - not shown - housing of an LED spotlight takes place.

As already mentioned, the central element of the arrangement according to the invention is the transparent light-guiding element 10, the configuration of which is to be explained in more detail below with reference to FIGS. 2 to 5. Viewed from the outside, the light-guiding element 10, which consists of a

translucent material, preferably made of a transparent plastic, formed substantially as a cylinder. The rear side of the cylinder forms a light entry surface 11 and accordingly faces the light sources. A disk-shaped recess 13 is formed over a circumferential edge region 12, which serves to receive the LEDs 5 shown schematically here, corresponding to the sectional representation of FIG. 5. About the back or the

corresponding light entry surface 11 will then be the light of the LEDs 5 in the

Lichtlenkelement 10 coupled. As already mentioned, it is desirable that the light of the LEDs 5 is mixed as well as possible. To achieve this, it is provided that the light entry surface 11 is provided with a light-scattering microstructure. The light-scattering effect of this structure achieves a uniform distribution of the light rays without extreme discontinuities. At the same time this ensures the desired color mixing. Alternatively to the embodiment in which the light entry surface 11 itself is provided with the structure, it could also be provided on the bottom surface of the

Recess 13, so between the LEDs 5 and the light entrance surface 11, a flat optical element, for example, insert a film with a corresponding microstructure. Also in this way, the above-mentioned uniform distribution of the light and a color mixing is achieved.

The forwarding of the light coupled into the light-directing element 10 then takes place essentially in two different ways, which are shown schematically in FIG

Sectional view of Figure 5 are shown.

Responsible for the further light line here is in particular the

In the illustrated embodiment, in which a symmetrical light output is sought, in this case the surface 15 is formed by a extending into the light-guiding element 10 recess 16, which is conical. The surface 15 is thereby formed inclined with respect to the longitudinal axis I of the cylinder and is formed by the lateral surface of the recess 16. Light rays which strike this surface 15 are now transmitted in different ways. Thus, a first part - represented by the light beam A - is emitted substantially unchanged to the bottom. In this case, a refraction, that is to say a slight deflection of the light beam A, can take place at the transition between the light-directing element 10 and the recess 16.

On the other hand, light rays which impinge on the surface 15 at a shallow angle (represented by the ray B) are totally reflected at the surface 15 and thereby directed towards the surface 18 of the cylinder. On this lateral surface 18, a later described structure 19 is provided, via which the light beams are coupled out and directed onto the reflection surface of the surrounding cup-shaped reflector 2. These light beams are then reflected by the reflector 2 again towards the bottom. In the end, therefore, both the light rays emitted by the LEDs 5 in the direction of light emission, that is to say downwards, and the light rays emitted laterally, that is to say the scattered light of the LEDs 5, are emitted towards the bottom side. The light distribution can be influenced by the choice of the opening angle of the conical recess 16. Here, the cone of the cone can be in the range between 0 ° and 45 °.

To the lateral surface 18 of the light-guiding element 10, it should be noted that the structure 19 provided there is preferably designed such that the Lichtlenkelement 10 laterally leaving rays as perpendicular to

Longitudinal axis I are delivered. This ensures that the light can be effectively deflected by the reflector 2 in the light emission direction. This preferred lateral light emission is achieved in that the structure 19 is again designed as a microprism structure. In particular, this structure is formed by an alternating arrangement over the circumference of the lateral surface 18 extending grooves and projections.

Finally, the combination of the light-directing element 10 with the reflector 2 opens up the possibility of achieving very narrow-beam light distributions, despite which a thorough mixing of the light of the LEDs 5 is achieved.

A second variant of a light-guiding element according to the invention is shown in FIGS. 6 to 8. This is a variant in which an asymmetric Li chtab radiation is achieved. For this purpose, forms the light entry surface eleventh

opposite surface 15 of the light guide member 10 is not the lateral surface of a conical recess. Instead, the surface 15 is now formed as a one-sided bevel or bevelled end face of the cylinder. As in the embodiment of Figures 1 to 5, a part of the light rays is the

Pass through the light guide 10 almost unhindered and leave over the surface 15. On the other hand, another part of the light rays is reflected on the surface 15 and emitted to the reflector 2 via the lateral surface 18. In this embodiment, then finally results in an asymmetric

Light emission characteristic, which could be used for example for the illumination of a wall or laterally arranged below the LED spotlight object. In this second exemplary embodiment, too, however, the light emitted by the LEDs is used completely for illumination, with effective mixing of the light again taking place.

Claims

claims

An arrangement (1) for emitting light with at least one substantially

point-shaped light source (5), one of the light source (5) in Ab beam direction upstream light-guiding element (10) made of a transparent material and a light-guiding element (10) surrounding the reflector (5),

characterized,

in that the light-directing element (10) is substantially cylindrical, wherein

• an end face of the cylinder forms a light entry surface (11),

The side of the cylinder opposite the light entry surface is at least partially inclined with respect to a longitudinal axis (I) of the cylinder such that it is transparent to one part of the light and reflective to another part of the light, and

• The lateral surface (18) of the cylinder is provided with structures (19) for light extraction.

2. Arrangement according to claim 1,

characterized,

the light entry surface (11) of the light guide element (10) is provided with a scattering structure, in particular a microstructure.

3. Arrangement according to claim 1,

characterized,

in that the light entry surface (11) of the light guide element (10) is an optical element, in particular a foil, having a scattering structure, in particular a

Microstructure is upstream.

4. Arrangement according to one of the preceding claims,

characterized,

in that the light exit surface (15) formed by the inclined surface of the

Light guide element (10) through the lateral surface (16) of a extending in the light guide element recess is formed.

5. Arrangement according to claim 4,

characterized,

the recess (16) is cone-shaped.

6. Arrangement according to claim 5,

characterized,

that the cone of the conical recess (16) is in the range between 0 ° and 45 °.

7. Arrangement according to one of claims 1 to 3,

characterized,

in that the light exit surface (15) formed by the inclined surface of the

Light-deflecting element (10) forms an oblique end face of the cylinder.

8. Arrangement according to one of the preceding claims,

characterized,

that the reflector (2) is cup-shaped.

9. Arrangement according to one of the preceding claims,

characterized,

that the light source is formed by an LED.

10. Arrangement according to claim 9,

characterized,

that it has several different colored LEDs.