Luminaire with a light guide for generating glare-free, partially diffused light.

Abstract

Luminaire with a luminaire housing (2) comprising a light-emitting surface, a light source comprising LEDs (10) for generating a luminous flux arranged in the luminaire housing (2) and control gear for operating the LEDs (10) and a light guide (4) arranged in the direction of radiation in front of the light source, which distributes and / or glare-free the light on a partial area of ​​the light-emitting surface, wherein the light guide (4) comprises a diffuse light-generating, translucent material and has a transparent material in a direct area immediately in one direction of radiation in front of the LEDs (10), MARKED BY THIS , that the transparent material in the direct area is designed to be usable in the light guide (4).

Description

[0001] The invention relates to a luminaire with a luminaire housing comprising a light exit surface, a luminous means arranged in the luminaire housing comprising LEDs for generating a luminous flux and electrical operating devices for operating the luminous means, as well as a light guide arranged in front of the luminous means in the radiation direction, which light guide distributes the light on a partial surface of the light exit surface and / or glares.

[0002] The light guide's function is to distribute the light generated by the LEDs over as large an area as possible, thus reducing luminance to avoid glare for users. The light guide thus provides glare control. However, the primary glare control is achieved by the reflector, which achieves glare control by lowering the light beam to an angle of 60° with the horizontal in a conventional manner.

[0003] The light emitted by the LEDs radiates not only into the area directly in front of the LEDs (direct area) but also into cavities located to the side of the LED strip, formed by the light guide and the luminaire housing as light spaces, and thus additionally illuminates the light guide to generate indirect light, which is why this lateral area is also referred to as the “indirect area”. Disadvantages of the state of the art

[0004] However, the light must also penetrate the material of the light guide above the LEDs of the LED strip, which is associated with a loss of light and also results in a less precise light distribution curve.

[0005] According to various directives, in particular the SELV (Safety Extra Low Voltage) directive, it must be ensured that a defined standard finger has no access to electrically conductive parts and can be connected to full ground potential.

[0006] For this purpose, the current state of the art places the light guide above current-carrying components, especially above the LED strip, so that the standard finger cannot access it. On the other hand, it is optically desirable to leave the area directly in front of the LEDs clear in the direction of radiation in order to optimize the light distribution curve and luminous efficacy.

[0007] As prior art, for example, US 6,161,939 A discloses a luminaire with a luminaire housing in which a light source comprising LEDs is arranged. The light source is designed to emit light into a light guide of the luminaire, which in some embodiments comprises translucent and transparent material. Further luminaires, each comprising a luminaire housing with a light source arranged therein and an optical element arranged in front of the light source, are known, for example, from DE 10 2011 017 725 A1, US 2012 0 182 713 A1, US 2009 0 323 323 A1, DE 10 2009 047 487 A1, and US 2012 0 327 652 A1. Task

[0008] Based on this prior art, the invention is based on the object of at least partially avoiding these disadvantages and in particular of realizing a luminaire and a light guide for a luminaire with an improved light distribution curve, in particular a uniform, i.e. homogeneously illuminating light exit surface of the luminaire.

[0009] According to the invention, this object is achieved by a luminaire comprising a luminaire housing comprising a light-emitting surface, a light source arranged in the luminaire housing comprising LEDs for generating a luminous flux, as well as operating devices for operating the LEDs, and a light guide arranged in front of the light source in the direction of radiation, which light guide distributes the light over a partial area of ​​the light-emitting surface and / or reduces glare. The light guide comprises a translucent material that generates diffuse light and, in a direct area directly in front of the LEDs in a direction of radiation, a transparent material. The transparent material is designed to be insertable into the light guide in the direct area.

[0010] One embodiment provides that the direct area comprises an insert made of clear plastic, which can be connected to the light guide or frame that otherwise produces diffuse light.

[0011] Furthermore, the cover of the direct area of ​​the light guide can be provided directly in front of the LEDs of the LED strip so that this light guide is SELV-compliant.

[0012] Preferred materials for the manufacture of the light guide are optical plastics, preferably PMMA or, for simpler designs, PC.

[0013] The luminaire is particularly well suited for use in coffered ceilings in suspended ceilings and can be used to illuminate parts of these surfaces.

[0014] Preferably, the light guides and the LED strips arranged above or above them, comprising a plurality of LEDs arranged linearly one behind the other and spaced apart from one another, are arranged in the longitudinal direction of the luminaire housing, so that the light is distributed over the surface of the light guides and emerges from the light exit surface on the front of the luminaire, specifically in such a way that only the light guide is illuminated. In this respect, not the entire front light exit surface of the luminaire is illuminated, but only the area of ​​the light guides, which is why this luminaire is also referred to as a luminaire with "partial light."

[0015] The luminaire according to the invention can be designed such that the light guides define or enclose light spaces with the luminaire housing, which can also have other geometric configurations or can be separated or set off from the rest of the luminaire housing by a ledge or a wall. Preferably, the light emitted by the LED strips enters this light space and is reflected within the light space. For this purpose, the walls of the light space are either themselves designed as reflectors or at least provided with a reflective paint or coating.

[0016] In the description, reference is made to the accompanying drawings, which form a part hereof, and serve to illustrate preferred embodiments of the invention. In this regard, directional terminology such as "top", "bottom", "front", "back", "fore", "rear", etc., is used with reference to the orientation in the described figure(s). Since components of embodiments can be positioned in a number of different orientations, the directional terminology is for the purpose of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural and logical changes may be made without departing from the scope of the present invention. The following detailed description is not to be taken in a limiting sense.Furthermore, terms such as "connected," "attached," and "integrated" are used throughout this description to describe both direct and indirect connections, direct or indirect connections, and direct or indirect integration. In the figures, identical or similar elements are provided with identical reference symbols where appropriate. They show: Fig. 1: a perspective top view of the luminaire housing of a luminaire not according to the invention; Fig. 2: a perspective view of the luminaire from below with two anti-glare devices arranged at opposite ends; Fig. 3: an enlarged section of a longitudinal section of the luminaire according to Fig. 1; Fig. 4: an enlarged perspective cross-section through a light space; Fig. 5: an enlarged view of the direct area of ​​a light guide; Fig. 6: an enlarged perspective top view of an alternative light guide with a test finger; Fig. 7: another enlarged plan view of the light guide according to Fig. 6; Fig. 8: an enlarged cross-section of the light guide with the test finger along the line VIII - VIII according to Fig. 6 and Fig. 9: an exploded view of an assembly comprising an LED strip, a light guide, a light guide holding frame and an insert reflector.

[0017] For clarification, the Fig. 6, Fig. 7 and Fig. 8 also shows a coordinate system. Thus, the X-axis is in the transverse direction of the luminaire, the Z-axis in the longitudinal direction, and the Y-axis in the height of the luminaire.

[0018] The luminaire shown therefore essentially consists of a box-shaped luminaire housing 2, preferably made of a folded profiled sheet metal, the rear upper side of which, in the installed position, is arranged towards a ceiling against the direction of light radiation, the front side of which is closed, and the front side of which is open and defines a front light-emitting surface enclosed by a flange-like, circumferential frame 2A, the free ends of which are folded upwards again to increase flexural rigidity. The luminaire housing 2 has a connection space 2B in the center and extending approximately over two-thirds of the width of the luminaire. On both sides, flatter light spaces 2C, 2D are connected by steps, which then finally merge into the frame 2A.These light spaces 2C, 2D are closed at the front by translucent light guides 4, 6, which cover LEDs arranged on LED strips that extend collinearly to each other in the longitudinal direction of the luminaire.

[0019] The front ends or edges of the light guides 4, 6 are flush with the front light-emitting surface, and the area between the light guides 4, 6 is closed by a removable, plate-shaped cover 2E, which is preferably held in place by locking springs or magnets. Behind this cover 2B is the connection compartment of the luminaire 2, which is raised relative to the side light compartments for the light guides 4, 6, namely by approximately one-third of the total height of the luminaire housing 2. Electrical and / or electronic components of the luminaire are arranged in this connection compartment.

[0020] Each light guide 4, 6 is designed as a translucent, one-piece injection-molded part with a central transverse web to form a direct area, which, in the installed position, extends transversely across the LEDs 10 of the LED strip 8 and is provided at the ends with two upper webs 4A, 4B extending transversely to the longitudinal direction and parallel to one another at a distance, which, together with the transverse web, span the LEDs 10 like a bridge and simultaneously serve as an insect protection device. Furthermore, each end of the central transverse web is designed with an arm 4C, 4D that initially projects linearly downwards and initially bends quite steeply (in this case at an angle of approximately 20 degrees to the vertical or110 degrees to the horizontal) extends downwards and thus has a light channel enclosing the direct area with a height of approximately 7 mm and a width of approximately 21 mm at the base, which corresponds to a preferred ratio of 1 to 3 (width / height). It then merges on both sides into wing-like, curved, transversely extending light surfaces 4E, FF of the same size, which extend outwards over three times the direct area in the transverse direction to form indirect areas adjacent to the central direct area. At the outer ends, the light guides finally merge into upwardly projecting, linear outer webs 4G, 4H, which extend to the inner top side of the light spaces 2C, 2D and, in the installed position, enclose the light spaces 2C, 2D on the outside.

[0021] In the direction of radiation directly in front of the LEDs 10, rectangular light openings 4I are provided which are associated with them and which allow the light emitted by the LEDs 10 to pass through directly below to generate the direct light.

[0022] For each LED 10 on the LED strip 8, such a light opening 4I is provided within the direct area of ​​the light guide 4, 6. The Fig. 4 and Fig. 5, has spacer collars 4J projecting in the direction of radiation on the underside of each light opening 4I, which extend circumferentially along the entire underside of the light opening 4I transversely to this light opening downwards. By means of these circumferential spacer collars 4J, the Fig. 6, Fig. 8 and Fig. 9, the test fingers 16 can no longer penetrate far enough into the light openings 4I to touch the current-carrying components, so that SELV conformity is ensured.

[0023] In addition, insert reflectors 18 are snapped into the light troughs of the light guides 4, 6 for glare control. These insert reflectors have a pyramidal or conical reflector surface 18A for each light opening 4I of the light guides 4, 6, widening in the beam direction. The height of the reflector surface is determined depending on the geometric arrangement of the reflector to the LED such that a beam from the outermost edge of the LED, forming an angle of less than or equal to 60 degrees to the plane defined by the surface of the LED, enters the inside of the reflector, thus reducing glare. In the present case, the insert reflector 18 is provided with a vapor-deposited aluminum layer to increase its reflective properties. This insert reflector 18 serves as a glare control device to prevent a user from directly viewing the LEDs 10 up to an angle of 60° below or with the horizontal.

[0024] The Fig. 6 to 8 show an alternatively designed spacer element which, in the area immediately adjacent to the rectangular LEDs 10, has projections 4K, 4L extending from the edge of the light opening 4I to the LEDs 10 instead of the spacer webs 4J, which also prevent the penetration of the test finger 16 into the light opening 4I. These projections 4K, 4L extend in the Z direction only approximately over one-third of the length of the LEDs 10 and nevertheless have the advantage that, due to their larger surface area, they can absorb significantly greater contact forces of over 10 Newtons without permanent damage, thus enabling even better SELV-compliant voltage protection.

[0025] The Fig.Figure 9 shows an exploded view of the assembly comprising the LED strip 8, a light guide 4, 6 completely enclosed by a light guide frame 20 surrounding the light guide, and the reflector insert 18. The light guide 4, 6 is snapped into corresponding openings in the top of the luminaire housing 2 in the area of ​​the light spaces 2C, 2D by means of several locking lugs 20A spaced apart in the longitudinal direction by the frame 20. Alternatively, the light guide 4, 6 can be directly equipped with fastening means for attachment to the luminaire housing without an additional light guide frame 20. List of reference symbols 2 luminaire housings 2A frame 2B Connection compartment 2C clearance 2D light space 2E Cover 4 light guides 4A Obersteg 4B Obersteg 4C Arm 4D Arm 4E light area 4F light area 4G outer bridge 4H outer bridge 4I Light opening 4J spacer collar 4K advantage 4L advantage 6 light guides 8 LED strips 10 LED 16 test fingers 18 Insert reflector 18A reflector surface 20 light guide holding frames 20A locking hook

Claims

[1] Luminaire with a luminaire housing (2) comprising a light exit surface, a light source arranged in the luminaire housing (2) comprising LEDs (10) for generating a luminous flux and operating devices for operating the LEDs (10) and a light guide (4) arranged in front of the light source in the radiation direction, which light guide distributes the light over a partial area of ​​the light exit surface and / or glares, wherein the light guide (4) comprises a diffuse light-generating, translucent material and has a transparent material in a direct area directly in front of the LEDs (10) in a radiation direction, MARKED BY that the transparent material in the direct area is designed to be insertable into the light guide (4). [2] Luminaire according to claim 1, MARKED BY that the light guide (4) has a light trough and that an insert reflector (18) can be inserted into this light trough. [3] Luminaire according to claim 2, MARKED BYthat the height of the light trough is about 3 times its width.

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