EP3002506B1 - Luminaire with direct and indirect lighting - Google Patents

Description

The present invention relates to a luminaire which emits a direct and an indirect light component.

From the prior art is known to form lamps for combined direct and indirect lighting. As a rule, various light sources are provided on a luminaire housing which provide either direct lighting or indirect lighting. However, the light sources are often visible in such lights.

In the field of hollow fiber optics, constructions are also known which provide an integrated light source for direct or indirect illumination. However, the ratio of the intensity between the direct and indirect components is difficult to set in such luminaires.

The US 2014/218964 A1 discloses a lighting module having a chamber and laterally arranged light sources. The chamber is closed on the top and bottom with partially reflective plates and possibly with other optical disks. Reflectors are arranged on the side and in the middle of the chamber. Comparable lights are also from the DE 10 2012 006 887 A1 and from the DE 10 2010 037 630 A1 known.

US Pat. No. 8,038,315 B1 discloses a luminaire housing with a printed bottom plate. The housing further has lighting means, the light of which is deflected via deflecting elements also in the direction of the side opposite the bottom plate. In particular, reflectors can be provided in this area, which redirect 80% or 100% of the light downwards.

The object of the present invention is to provide a luminaire which has a direct and an indirect light component, wherein the position of the light sources can not be seen when looking at the luminaire and wherein the luminance of the direct component is greatly reduced compared to the luminance of the light sources.

The problem is solved by a luminaire according to claim 1.

According to the invention, a hollow chamber is provided which emits light downwards through a light exit surface and also emits an indirect light component upward through an at least partially transparent rear side. Of particular advantage in this case are the optical elements which allow the light of the semiconductor light sources to be directed in the direction of the at least partially reflecting rear side in order to be able to set the proportion of the light which is available for the direct illumination and for the indirect illumination. As light sources linearly arranged semiconductor light sources, for example LEDs or OLEDs (light emitting devices or organic light emitting devices) are used. Due to their relatively small size and the arrangement in one or more rows, the Semiconductor light sources are placed completely hidden in the hollow chamber. Because the light for direct illumination is deflected by diffuse reflection at the rear in the direction of the light exit surface, the local arrangement of the light sources and the structuring (eg individual light points in LEDs) can not be identified from below when looking at the luminaire. This allows for pleasant direct lighting, without causing glare even with direct view of the lamp.

According to a preferred embodiment, the optical elements comprise one or more reflectors, which in particular have high-gloss and / or matt-reflecting surfaces. High-gloss reflective surfaces offer high efficiency. Since the light is deflected at the preferably diffusely reflecting back of the hollow chamber in the direction of the light exit surface, no glare is to be feared even with highly reflective optical elements. When using matt reflective optical elements, however, the light distribution can be evened out even more. In this embodiment, it is also possible to form a region of the reflective back of a high-gloss material. Furthermore, matt reflective optical elements are advantageous for embodiments in which part of the light emitted by the optical elements leaves the luminaire directly through the light exit surface as a direct component.

According to a preferred embodiment, the optical elements in the form of reflectors on a longitudinal extent, which is parallel to the linearly arranged semiconductor light sources. As a result, the light can be deflected in the direction of the partially reflecting rear side over the entire length of the light sources. According to a further embodiment, it may further be provided that the reflectors have a concave curvature, in particular in the form of a cylindrical portion with a longitudinal extent parallel to the linear semiconductor light source. Due to the curvature, the light of the light sources, which is directed onto the reflective area of the rear side, can be distributed uniformly over the rear side.

According to a preferred embodiment, the optical elements can also have a transparent medium for directing the light. For example, the optical elements may comprise optical fibers or lens bodies.

According to a preferred embodiment, the optical elements are movable relative to the semiconductor light sources, whereby it is possible to adjust the proportion of the light deflected at the optical elements in the direction towards the rear side. For example, the optical elements may be movable in a direction perpendicular to the longitudinal extent of the semiconductor light sources. As a result of a displacement of the optical elements, more or less light can thereby be deflected onto a reflective region of the rear side, which is provided between the optical elements. Furthermore, it is possible to set the mixed color of the light, which is emitted via the partially reflecting rear side in the direction of the light exit surface, by movements of the optical elements in the case of a plurality of semiconductor light sources arranged in parallel with different colors.

According to the invention, the rear side is designed to be diffusely reflective in a region between two of the optical elements. In particular, the entire area between two of the optical elements may be diffusely reflected. In this embodiment, the light of the semiconductor light sources is directed by the optical elements to the region between the optical elements, which preferably serves exclusively for the reflection of light to the light exit surface. Furthermore, according to the invention, the partial regions between the optical elements and the edges of the luminaire are designed as light-permeable partial regions of the rear side. In this embodiment, the edge regions of the rear side between the edges of the lamp and the optical elements for emitting the indirect light portion and the area between the optical elements for deflecting the light in the direction of the light exit surface for the direct light portion.

According to a preferred embodiment, a transparent cover is arranged in the light exit surface. According to one embodiment, the transparent cover may be formed as a simple transparent plate. The cover can provide protection for the hollow chamber in particular against pollution in this embodiment. On the transparent cover, according to a preferred embodiment, refractive structures may also be provided on the inside or outside. For example, the refractive structures may have prismatic, conical, parabolic, hemispherical, and / or hexagonal shapes. Such structures are suitable for better distributing the light which passes through the cover. In particular, this makes it possible to deliver the direct light component with a narrower light distribution, as a result of which the glare suppression of the luminaire is improved. For example, a shield can be achieved in which the luminance drops above a critical angle. Furthermore, a Batwing distribution is possible. The use of round or hexagonal structures also allows a good homogeneity of the light distribution over all C-planes (vertical sectional plane of the luminaire through the center of gravity).

The cover can be clearly transparent or diffusely transparent. A diffuse cover allows the light to be scattered to such an extent that it is also possible to comply with limit values with regard to direct glare with direct view of the luminaire, even with powerful light sources.

The semiconductor light sources can in particular generate white light. It is also provided in accordance with preferred embodiments to provide white light sources in the range between warm white and cold white. Preferably, the light of the cold white semiconductor light sources is used for the indirect illumination, while the light of the warm white semiconductor light sources is preferably used via the optical elements for reflection on the back to generate the direct component. It is also possible to use colors other than just whites for the semiconductor light sources. For example, blue shades, in particular for the production of Indirektanteils be used. According to a development of this embodiment, the semiconductor light sources of different colors are separately switchable or dimmable. For example, this can mix warm white and cool white shades to produce different shades of white. Additionally or alternatively, the optical elements can also be moved, whereby likewise the proportion of the light of colored semiconductor light elements for the direct component and the indirect component can be mixed differently.

According to a preferred embodiment, the semiconductor light sources are arranged in a plurality of parallel rows, wherein the parallel rows are arranged in particular parallel to the longitudinal extent of the optical elements. In this embodiment, the light can be supplied to a linear semiconductor light source via the optical element uniformly over the length of the lamp to the direct component and the indirect component.

According to a preferred embodiment, refractive structures are also provided on the partially translucent rear side of the hollow chamber. In particular, symmetrically or asymmetrically shaped linear prisms on the inside or outside of the Rear be provided to influence the light distribution of the indirect component. An asymmetrical light distribution for the indirect component is preferred, for example, in applications in which the luminaire is to be mounted in the vicinity of a wall or a ceiling. Here, it is desirable if as much light as possible is emitted in the direction of the interior of the room, while only a smaller proportion of the light is emitted in the direction of the wall. For luminaires mounted in the middle of the room, however, a symmetrical distribution of the indirect component is an advantage, in order to achieve a uniform illumination of the ceiling.

According to a preferred embodiment, the optical elements are arranged with respect to the light sources such that the light, which is deflected by the optical elements, does not exit the luminaire directly through the light exit surface. According to the invention, the luminaire is set up so that no light from the LEDs leaves the luminaire directly through the light exit surface. This ensures that all the light leaving the luminaire as a direct component has been reflected at least once in the luminaire before it exits the light exit surface. This achieves the effect that the direct illumination is formed only by stray light. On the other hand, the light for the indirect component can leave the luminaire directly from the LEDs through the translucent areas of the back.

Figur 1

zeigt einen Querschnitt durch eine erste Ausführungsform einer Leuchte.

Figur 2

zeigt die Leuchte nach Figur 1 in perspektivischer Ansicht von schräg unten ohne Abdeckung in der Lichtaustrittsfläche.

Figur 3

zeigt den Querschnitt nach Figur 1 mit mehreren Lichtpfaden.

Figur 4

zeigt einen Querschnitt durch eine Leuchte ähnlich der Figur 1, jedoch mit verstellbaren optischen Elementen.

Figur 5

zeigt einen Ausschnitt einer Leuchte ähnlich der Figur 4 im Bereich des optischen Elements und der Halbleiterlichtquellen mit einer Öffnung als lichtdurchlässigen Teilbereich oberhalb des optischen Elementes.

Figur 6

zeigt eine Leuchte als Vergleichsbeispiel im Querschnitt.

Figur 7

zeigt einen schematischen Querschnitt durch eine Leuchte einer weiteren Ausführungsform, wobei ein Teil der Rückseite vergrößert dargestellt ist.

Figuren 8A&B

zeigen die Lichtstärkeverteilung in einem Polardiagramm von zwei Leuchten mit symmetrischem bzw. asymmetrischem Indirektanteil.

Other features and advantages of the present invention will become apparent from the following description of preferred embodiments, taken in conjunction with the accompanying drawings. The figures show the following:

FIG. 1

shows a cross section through a first embodiment of a lamp.

FIG. 2

shows the light after FIG. 1 in a perspective view obliquely from below without cover in the light exit surface.

FIG. 3

shows the cross section FIG. 1 with several light paths.

FIG. 4

shows a cross section through a lamp similar to the FIG. 1 , but with adjustable optical elements.

FIG. 5

shows a section of a lamp similar to the FIG. 4 in the region of the optical element and the semiconductor light sources with an opening as a translucent subregion above the optical element.

FIG. 6

shows a lamp as a comparative example in cross section.

FIG. 7

shows a schematic cross section through a lamp of another embodiment, wherein a part of the back is shown enlarged.

Figures 8A & B

show the luminous intensity distribution in a polar diagram of two luminaires with symmetrical or asymmetrical indirect components.

Referring to the FIGS. 1 to 3 a luminaire is shown according to a first embodiment. The luminaire comprises a hollow chamber 1, in which laterally linear semiconductor light sources 2 are arranged. In the embodiment shown, the linear semiconductor light sources 2 are formed by two rows of LEDs whose longitudinal extent is perpendicular to the image plane of the FIGS. 1 and 3 runs and which are each arranged in the region of the outer longitudinal edges of the hollow chamber adjacent to a light exit surface. The light exit surface extends on the underside of the hollow chamber 1 and is closed with a transparent cover. The cover may be a simple translucent plate, for example of PMMA, PU or glass in this embodiment.

On the opposite side of the light exit surface 3 4 of the hollow chamber 1 different portions are formed. A middle portion 4A is formed light-reflecting, wherein on the side facing the hollow chamber inside a matt reflective surface is provided. In the lateral area along the longitudinal edges of the hollow chamber 1, transparent partial areas 4B are provided in the rear side 4.

Within the hollow chamber 1 in the region above and parallel to the linear semiconductor light sources 2 optical elements 5 are provided in the form of high-gloss reflectors with a cylindrical curvature.

FIG. 3 shows examples of light paths in the luminaire. The light path I extends from the light source 2 directly to the diffusely reflecting part of the back 4 and is diffusely reflected there towards the light exit surface 3. A large part of the light reflected on the rear side 4A leaves the luminaire through the cover of the light exit surface 3. Another part of the reflected light is reflected on the cover in the light exit surface 3. This light is again reflected by the reflective portion 4A of the back 4 (not shown in the figures) and deflected again in the direction of the light exit surface 3.

A second light path II extends from the semiconductor light source 2 to the optical element 5 and is reflected there by the cylindrically curved, highly reflective reflection surface in the direction of the diffusely reflecting portion 4A of the back 4. From there, the further course is similar to the light path I.

A light path III extends from the semiconductor light source 2 to the transparent portion 4B of the back 4 and exits there from the lamp. The transparent portion 4B is provided with a diffusing screen, so that the transmitted light is diffused diffusely.

A fourth light path IV extends from the light source 2 to a side wall of the hollow chamber 1 and is reflected there to the transparent part 4B of the back 4 and leaves the lamp through the portion 4B similar to the light path III.

The light of the light paths I and II, which leaves the light through the light exit surface 3, forms the portion of the light for a direct illumination of the room. The light which, according to the light paths III and IV, leaves the luminaire upwards through the transparent partial regions 4B forms the indirect light component for illuminating the ceiling of the room.

The optical elements 5 are arranged above the semiconductor light sources 2 in the illustrated embodiment. In general, they ensure that the light of the semiconductor light sources 2 is largely distributed over the entire width of the reflective area 4A of the rear side, in order to be reflected therefrom in the direction of the light exit surface 3. The arrangement of the optical elements 5, the proportion of the light incident on the reflective portion 4A of the back 4, distributed more evenly and possibly increased.

According to an alternative embodiment, in FIG. 4 is shown, the optical elements 5 may also be movable, in which embodiment the optical elements 5 are displaceable perpendicular to the longitudinal extent of the semiconductor light sources 2. The shift changes the ratio between light which leaves the luminaire through the light exit surface 3 for direct illumination and through the transparent partial regions 4B of the back 4 for indirect illumination. By matte reflective areas parallel to the back 4, which are moved with the optical elements 5, it is further ensured that the area 4A of the back 4 between the optical elements 5 is continuously light-reflecting, regardless of the position of the optical elements. 5

The semiconductor light sources 2 may be arranged below the optical elements 5 in the form of one or more rows of LEDs or OLEDs. The FIG. 5 shows an example in which two rows of light sources are arranged parallel to each other below the optical element 5. In this embodiment, the semiconductor light sources in the respective outer row produce a colder white hue and the semiconductor light source in the respective inner row produce a warmer white hue. In this example, the light of the warm white LEDs is directed predominantly via the optical element 5 in the central region of the back, from where it is discharged through the light exit surface and possibly the cover as direct light, whereas the light of the cold white LEDs predominantly the back 4th the light through the translucent portion 4B, which is formed in one embodiment as an opening in the back 4, leaves as an indirect component. In this way, the indirect component may have a different hue than the direct component. In connection with the embodiment according to FIG. 4 , in which the optical element can be moved perpendicular to the longitudinal extent of the semiconductor light source rows, even the intensity and hue of the light components for direct lighting and indirect lighting can be adjusted because more or less light of the semiconductor light sources arranged in parallel in each case the lamp as a direct component or as Indirektanteil leaves.

The semiconductor light sources 2 are predetermined on boards, which are arranged in particular next to the light exit surface 3 in the hollow light chamber 1, as in the FIGS. 1 and 3 to 5 shown. The boards are mounted horizontally on the side or on the cover of the light exit surface 3, so that they are not visible from below.

FIG. 6 shows a comparative example of a lamp in which the light sources 2 are not arranged horizontally in the luminaire, but are arranged on the vertical side surfaces of the hollow chamber 1. The optical elements 5 'in this luminaire are planar reflector surfaces, which are designed to be reflective on the side in the direction of the semiconductor light sources. The beam path is in FIG. 6 shown. A part of the light of the semiconductor light sources 2 is reflected at the optical elements 5 'and directed toward the central area 4A of the rear surface, which diffuses the light diffusely. A part of the radiation also passes directly from the semiconductor light sources 2 to this subarea 4A. Another part of the light (in the FIG. 6 not shown as a beam path) leaves the light from the semiconductor light sources 2 directly through the translucent subregions 4B of the back 4 and thereby ensures the indirect component. Also in the light of the FIG. 6 For example, the optical elements 5 'can be movable. In this luminaire, the optical elements can be rotatable so that the angle of inclination relative to the main emission direction of the semiconductor light sources 2 is adjustable. This also makes it possible to set the proportion of light which leaves the luminaire as a direct component or as an indirect component.

In the described embodiments, the light exit surface 3 is closed by a cover. The cover may be formed of clear transparent plastic, wherein on the inside or on the outside refractive structures are provided. Preference is given to refractive structures in the form of conical structures (not shown in the figures). The conical structures reduce the luminance in the direction that is decisive for reflected glare, for example on a screen surface. The conical structures reduce the luminance at higher angles (eg from 65 ° or 69 °) compared to the surface normal of the light exit surface. An advantage of this embodiment is that the light exit surface illuminates relatively evenly apart from the edge regions. The reason is to be seen in that the arrangement of the semiconductor light sources 2 and the optical elements of the diffuse reflecting region 4A of the back 4 is illuminated relatively uniformly. Through the cover, in particular by a cover with light-scattering structures, the light is distributed evenly. This creates the visual impression of a uniformly illuminated light exit surface, which is often perceived as aesthetically pleasing.

The optical elements 5, 5 'has been described in the preceding embodiments as reflectors with or without curvature. The reflectors can be designed highly reflective, in order to achieve a high efficiency for the light control. According to alternative embodiments, the reflectors may also be made matt. This is particularly advantageous if light from optical elements also leaves the luminaire directly through the light exit surface 3. According to alternative embodiments, the optical elements may also be in the form of light-guiding bodies or lens bodies which direct the light by refraction of light in a manner similar to the previously described reflective optical elements. Also, the optical elements of refractive material may be movably disposed in the hollow chamber to adjust the ratio between the direct and indirect components.

The rear side 4 is partially diffusely reflective in the region 4A and partially transparent in the region 4B. In one embodiment, the back 4 may be formed of a material that reflects a portion of the light and passes another portion of the light, e.g. in the form of a diffuser. In this case, the entire back of the lamp may be formed of a single material. However, the region 4A in the center of the luminaire is preferably made to be matt-reflective with respect to the light exit surface, and at least one other region 4B of the rear side is predominantly transparent. The area 4B may also be formed as an opening to form the translucent portion. Alternatively, the translucent subregion is formed as a transparent or translucent subregion, that is to say of a light-permeable material.

In one embodiment, the backside has a clear element on which a pattern of diffusely reflecting white paint is applied, e.g. by screen printing to form the areas 4A and 4B. This has the advantage that the spatial distribution of the diffuse reflecting region 4A can be adapted very specifically.

According to a further embodiment, schematically in the FIG. 7 is shown (the FIG. 7 shows no details inside the hollow chamber), the back 4 is provided with optically structured elements. In this embodiment, a transparent plate with downwardly facing prism elements 6 is arranged on the back, as in the enlarged detail of FIG. 7 is shown. The prism elements 6 are asymmetrically shaped in this embodiment, whereby the light, which is the lamp for the indirect component leaves, has an asymmetric light distribution. The light distribution is exemplary in FIG. 8B shown. It can be seen that the downward-pointing area (angle of -90 ° over 0 ° to 90 °) is symmetrical, while the light distribution for the indirect portion (angle range of 90 ° over 180 ° to -90 °) is asymmetrically distorted. The Figure 8A In contrast, shows a light distribution of a corresponding lamp with a back 4, which has no or only symmetrically arranged refractive structures. In this embodiment, the light component of the indirect lighting is symmetrical. In the Figures 8A and 8B The lines with circular and square symbols represent the light distributions measured in two different C-planes 0 ° -180 ° and 90 ° -270 ° of the luminaire.

Further variants of the embodiments presented above are possible within the scope of the invention, which is defined by the claims. The light exit surface 3 of the lamp, as described above, can be closed with a cover. In general, defoaming structures are also preferred for the cover. For example, conical, prismatic or parabolic, hemispherical or hexagonal shapes may be provided on the inside or on the outside of the cover for the light exit surface 3. In simple embodiments, the cover may also be formed by a clear plane-parallel disc or the light exit surface may be open.

Furthermore, different colors of LEDs or OLEDs can be used. A combination of red, green and blue LEDs is also possible to mix light of a desired light color. Due to the different dimming of the described LEDs, the color temperature in the case of white light or the color of the light in the case of colored light sources can be changed. For example, the in FIG. 5 shown parallel rows of LEDs are switched differently or dimmed to change the proportion of direct and indirect light and the light color.

LIST OF REFERENCE NUMBERS

1

hollow

2

Semiconductor light source

3

Light exit surface possibly with transparent cover

4

back

4A

reflective part

4B

translucent section

5, 5 '

optical elements

6

prism elements

I

first light path

II

second light path

III

third light path

IV

fourth light path

Claims (14)

1. Luminaire comprising the following:

   a hollow chamber (1) having a light exit surface (3) and a rear side (4) opposite the light exit surface,

   linearly arranged semiconductor light sources (2) mounted on opposite sides laterally adjacent the light exit surface, and

   optical elements (5) which direct a part of the light of the semiconductor light sources (2) towards the rear side (4),

   wherein the rear side (4) is partially translucent and partially reflective, in particular diffusely reflective, so that the light incident thereon is partially reflected in direction to the light exit surface to produce a direct illumination and partially passes through the rear side to produce an indirect illumination,

   the back side (4) comprising a region (4A) between two of the optical elements (5) that is diffusely reflective, and

   the rear side comprises one or more light-transmissive, in particular transparent or translucent partial regions (4B), characterized in that the one or more light-transmissive partial regions are each arranged between one of the two optical elements (5) and an outer edge of the luminaire, no light from the LEDs emerging directly from the luminaire without prior reflection through the light-emitting surface.
2. Luminaire according to claim 1, the optical elements (5, 5') comprising one or more reflectors, in particular having high-gloss and/or matt reflecting surfaces.
3. Luminaire according to claim 2, wherein the reflector or reflectors have a longitudinal extension which runs parallel to the linearly arranged semiconductor light sources (2) and/or wherein the reflector or reflectors are concave curved in the direction of one of the semiconductor light sources (2), in particular have the shape of a cylinder section.
4. Luminaire according to one of the preceding claims, the optical elements (5, 5') having a transparent medium for directing light.
5. Luminaire according to one of the preceding claims, the optical elements (5, 5') being movable relative to the semiconductor light sources (2), in particular being displaceable perpendicularly to the longitudinal extent of the semiconductor light sources (2), or being rotatable about an axis parallel to the longitudinal extent of the semiconductor light sources (2).
6. Luminaire according to one of the preceding claims, the entire region (4A) between the two optical elements being diffusely reflective.
7. Luminaire according to one of the preceding claims, wherein an at least partially transparent cover, in particular a transparent plate, is arranged in the light exit surface (3).
8. Luminaire according to claim 7, the cover having refractive structures on the inside and/or outside,
   wherein the refractive structures, in particular prismatic, conical, parabolic, hemispherical and/or hexagonal, have shapes.
9. Luminaire conforming to any of claims 7 to 8, the cover being clearly transparent or translucent.
10. Luminaire conforming to one of the preceding claims, the semiconductor light sources producing white light, in particular warm white and/or cold white light.
11. Luminaire according to one of the preceding claims, wherein the semiconductor light sources (2) comprise a plurality of semiconductor light sources each having a different light colour, wherein the semiconductor light sources in the different light colours are preferably separately switchable and/or dimmable.
12. Luminaire according to one of the preceding claims, wherein no light which is deflected by the optical elements leaves the luminaire directly through the light exit surface.
13. Luminaire according to one of the preceding claims, the semiconductor light sources (2) being arranged in a plurality of parallel rows, in particular parallel to a longitudinal extension of the optical elements (5).
14. Luminaire according to one of the preceding claims, the rear face (4) comprising refracting structures, in particular symmetrically or asymmetrically shaped linear prisms (6).

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