DE102010039306A1 - Arrangement for emitting light with light guide element and reflector - Google Patents

Abstract

An arrangement (1) for emitting light has at least one essentially point-shaped light source (5), a light guide element (10) made of a transparent material upstream of the light source (5) in the radiation direction, and a reflector (5) surrounding the light guide element (10). The light directing element (10) is essentially cylindrical, an end face of the cylinder forming a light entry surface (11), the side of the cylinder opposite the light entry surface being at least partially inclined relative to a longitudinal axis (I) of the cylinder in such a way that it covers part of the Light is permeable and reflective to another part of the light, and the outer surface (18) of the cylinder is provided with structures (19) for coupling out light.

Description

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 the actual light output is to take place in a luminaire construction, 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 specially designed light-guiding element, with the aid of which, on the one hand, an effective light control is made possible, on the other hand, the mixing of the light emitted by the light source (s) 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 thus transparent to some of the light and reflective for another part of the light, in which case the reflected portion of the light is emitted via the lateral surface of the cylinder, which is provided with structures for light extraction, to a reflector surrounding the light guide element. 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 punctiform light source, a light source in the emission direction of a light-guiding element made of a transparent material and a reflector surrounding the light guide element, wherein according to the invention, the light guide element is substantially cylindrical, wherein an end face of Cylinder forms a light entrance surface and the light inlet surface opposite side of the cylinder is at least partially inclined relative to a longitudinal axis of the cylinder such 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 with structures for Light extraction is provided.

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, in particular a microstructure, can also be provided in the region of the light entry surface.

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 guide element, ie the side opposite the light entry surface, is preferably formed by a lateral surface of a recess extending into the light guide element, wherein the recess is, for example, conical. Depending on how narrow - emitting the light output should be, then the cone of the Cone are chosen. This can be in particular in the range between 0 ° and 45 °.

As an alternative to a symmetrical light output, however, an asymmetrical light output can also be provided. In this case, the surface of the light-directing element opposite the light entry surface, on which, on the one hand, a refraction of light and, on the other hand, a reflection takes place, is preferably formed by an oblique end 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:

1 a first embodiment of an inventive arrangement for light emission;

2 to 4 Views of the coming in the first embodiment used light-steering element;

5 a sectional view of the light-guiding element of 2 to 4 and

6 to 8th Views of a second embodiment of a light-guiding element, by means of which an asymmetrical light output is achieved.

In the 1 generally with the reference numeral 1 provided arrangement of the invention serves to direct the light of the light, which is emitted by a plurality of point-shaped 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 help of the inventive arrangement 1 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 order 1 can be used for example in so-called LED spotlights.

Essential elements of the arrangement according to the invention 1 are on the one hand a cup-shaped reflector 2 and on the other hand, a transparent light-guiding element 10 which is approximately in the area of the center of the reflector 2 is arranged. The embodiment of the light-guiding element 10 will be described in detail below. Both elements, so reflector 2 and light-guiding element 10 , Be by an annular ausgestaltetes holding element 3 held over which at the same time 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 , whose configuration is described below with reference to 2 to 5 will be explained in more detail.

Seen from the outside is the light-guiding element 10 , which consists of a translucent material, preferably of a transparent plastic, formed substantially as a cylinder. The back of the cylinder forms a light entry surface 11 and accordingly faces the light sources. Over a peripheral edge area 12 becomes a disc-shaped recess 13 formed, which according to the sectional view of 5 the recording of the LEDs shown here schematically 5 serves. Over the back or the corresponding light entry surface 11 then becomes the light of the LEDs 5 in the light guide element 10 coupled.

As already mentioned, it is desirable that the light of the LEDs 5 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 provided with the structure could also be provided on the bottom surface of the recess 13 that is, between the LEDs 5 and the light entry 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 in the steering element 10 coupled light then takes place essentially in two different ways, which schematically in the sectional view of 5 are shown.

Responsible for the further light pipe here is in particular the light entrance surface 11 of the light-guiding element 10 opposite surface 15 , In the illustrated embodiment, in which a symmetrical light output is sought, in this case the area 15 through a into the light guide element 10 extending recess 16 formed, which is cone-shaped. The area 15 is thereby inclined relative to the longitudinal axis I of the cylinder and is formed by the lateral surface of the recess 16 educated.

Beams of light on this surface 15 meet, are now forwarded in different ways. Thus, a first part - represented by the light beam A - is emitted substantially unchanged to the bottom. At the transition between the light guide element 10 and the recess 16 In this case, a refraction, so a slight deflection of the light beam A take place. Light rays, however, which at a shallow angle to the surface 15 hit (represented by the beam B), be on the surface 15 totally reflected and thereby on the lateral surface 18 of the cylinder. On this lateral surface 18 is a structure described in more detail later 19 provided, via which the light beams coupled out and on the reflection surface of the surrounding cup-shaped reflector 2 be steered. These light rays are then from the reflector 2 again reflected to the bottom. Ultimately, therefore, both of the LEDs 5 in the light emission direction, ie downwardly emitted light rays, as well as the laterally emitted light rays, so the scattered light of the LEDs 5 directed towards the bottom. The light distribution can in this case by the choice of the opening angle of the conical recess 16 to be influenced. 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 provided there 19 is preferably configured such that the light-guiding element 10 laterally leaving rays are emitted as perpendicular to the longitudinal axis I as possible. This ensures that the light is effectively transmitted through the reflector 2 can be deflected in the light emission direction. This preferred lateral light output is achieved by the structure 19 again designed as a microprism structure. In particular, this structure is replaced by an alternating arrangement over the circumference of the lateral surface 18 extending grooves and projections formed.

Ultimately, by the combination of the light-guiding element 10 with the reflector 2 opens up the possibility to achieve very narrow beam light distributions, despite all a good mixing of the light of the LEDs 5 is achieved.

A second variant of a light-guiding element according to the invention is in the 6 to 8th shown. This is a variant in which an asymmetrical light emission is achieved. For this purpose, forms the light entrance surface 11 opposite surface 15 of the light-guiding element 10 not the lateral surface of a conical recess. Instead, the area is 15 now formed as a one-sided bevel or beveled end face of the cylinder. As in the embodiment of the 1 to 5 Part of the light rays becomes the light-guiding element 10 radiate through almost unhindered and over the surface 15 leave. Another part of the light rays, on the other hand, is on the surface 15 reflected and over the lateral surface 18 on the reflector 2 be delivered. In the case of this embodiment, an asymmetrical light emission characteristic ultimately results, which could be used, for example, for illuminating a wall or an object arranged laterally below the LED emitter. 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 (10)

Arrangement ( 1 ) for emitting light with at least one substantially punctiform light source ( 5 ), one of the light source ( 5 ) in the emission direction upstream light-guiding element ( 10 ) of a transparent material and a light-guiding element ( 10 ) surrounding reflector ( 5 ), characterized in that the light-guiding element ( 10 ) is formed substantially cylinder-like, wherein • an end face of the cylinder has 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 18 ) of the cylinder with structures ( 19 ) is provided for light extraction. Arrangement according to claim 1, characterized in that the light entry surface ( 11 ) of the light-guiding element ( 10 ) is provided with a scattering structure, in particular a microstructure. Arrangement according to claim 1, characterized in that the light entry surface ( 11 ) of Light guide element ( 10 ) an optical element, in particular a film, is arranged upstream with a scattering structure, in particular a microstructure. Arrangement according to one of the preceding claims, characterized in that the light exit surface formed by the inclined surface ( 15 ) of the light-guiding element ( 10 ) through the lateral surface ( 16 ) is formed in the light guide element extending recess. Arrangement according to claim 4, characterized in that the recess ( 16 ) is cone-shaped. Arrangement according to claim 5, characterized in that the cone of the conical recess ( 16 ) is in the range between 0 ° and 45 °. Arrangement according to one of claims 1 to 3, characterized in that the light exit surface formed by the inclined surface ( 15 ) of the light-guiding element ( 10 ) forms an inclined end face of the cylinder. Arrangement according to one of the preceding claims, characterized in that the reflector ( 2 ) is cup-shaped. Arrangement according to one of the preceding claims, characterized in that the light source is formed by an LED. Arrangement according to claim 9, characterized in that it comprises a plurality of different colored LEDs.

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