Elongated lamp

Abstract

The invention relates to a light fixture (100) having: an elongate light source, which is formed by multiple LEDs (60) or LED clusters arranged one behind the other in the longitudinal direction; a primary optical system (20), which is assigned to the light source and is formed by multiple pot-like reflectors (25), which are arranged one behind the other in the longitudinal direction and each widen in a divergent manner from the light source in a light emission direction of the light fixture (100); and a secondary optical system (30), which follows the primary optical system (20) in the light emission direction and is formed by a planar element consisting of a transparent material, wherein the element has light-refractive structures (35).

Description

[0001] The present invention relates to an elongated luminaire designed to emit a high amount of light without glare over a narrow light emission area.

[0002] Linear lighting solutions are used in a variety of ways in lighting technology and are available both as individual luminaires and as elongated strip lights. Due to their narrow design, these luminaires or strip lights are often distinguished by their elegant appearance compared to large-area luminaires, which is why they are used in a wide variety of applications.

[0003] If such luminaires are to be used to illuminate workplaces, they must emit a sufficiently high amount of light to meet the requirements of standard workplace lighting. The usual solution to date for creating a narrow, linear luminaire has been to use several LED modules arranged one behind the other, enclosed in a white or mirrored trough reflector. Below the reflector is an optical sandwich consisting of diffusing foils and light-refracting structures to ensure the glare control required for workplace lighting. Alternatively, pot-shaped reflectors associated with the LEDs have been used to influence the light. These reflectors are open at the bottom, allowing direct visibility into the luminaire.

[0004] Currently, there is a clear trend toward making luminaires increasingly narrower, while still aiming to increase the amount of light emitted. For example, it would be desirable to provide luminaires with a light emission area of ​​only approximately 30 mm. At the same time, however, the light-emitting surface of the luminaire should appear as homogeneous as possible, which rules out the use of the aforementioned individual reflectors open at the bottom. Instead, solutions are being sought that, despite a narrow light emission opening and homogeneous light emission, can emit a high amount of light, while also meeting the requirements for glare control suitable for work purposes.

[0005] EP 2 636 943 A1 discloses an LED lamp set for improving illumination and eliminating ghost images. The lampshade (20), a diffusion membrane (10), and a circuit board (30), comprise a plurality of light shells (23), each of which has a housing chamber (24) for accommodating at least one LED (40). The diffusion membrane (10) covers the light-exit surface (271), is made of a transparent material, and has a plurality of transparent bumps (11) on its surface.

[0006] US 2018 / 0022268 A1 provides an LED automotive lamp comprising an outer shell, two support components, a main control board, and an illumination lamp group, wherein the illumination lamp group comprises a plurality of LED illumination lamp spheres equidistantly welded to the main control board and a plurality of illumination light shell components arranged side by side on the main control board and covering the plurality of LED illumination lamp spheres, respectively.

[0007] KR 101275514 B1 specifies a lighting device for a zebra crossing that can adjust the beam angle of the light. This lighting device for a zebra crossing is provided to radiate light far toward the opposite side of a road.

[0008] The present invention is based on the object of providing a corresponding luminaire which meets the above-mentioned criteria with regard to its light output.

[0009] The stated object is achieved by a luminaire having the features of claim 1. Advantageous developments of the invention are the subject of the dependent claims.

[0010] In the solution according to the invention, the elongated light source is formed by several LEDs or LED clusters arranged one behind the other in the longitudinal direction. Homogeneous light emission across the entire surface of the elongated, narrow light exit opening is achieved with the aid of a plate-shaped element made of a transparent material with light-refracting structures. However, according to the invention, a primary optic is provided upstream of this plate-shaped element. This primary optic is formed by several pot-shaped reflectors arranged one behind the other in the longitudinal direction, each of which diverges from the light source in a light emission direction of the luminaire.It has been shown that the interaction of the pot-shaped reflectors with the light-refracting secondary optics allows for efficient light control even at high so-called lumen outputs, such that the light ultimately emitted by the luminaire meets the requirements for satisfactory glare control, in particular such that the condition UGR<19 can be met.

[0011] According to the present invention, a luminaire is thus proposed which comprises: an elongated light source which is formed by a plurality of LEDs or LED clusters arranged one behind the other in the longitudinal direction, a primary optic assigned to the light source which is formed by a plurality of pot-shaped reflectors arranged one behind the other in the longitudinal direction, each of which diverges from the light source in a light emission direction of the luminaire, a secondary optic following the primary optic in the light emission direction, which is formed by a plate-shaped element made of a transparent material, wherein the plate-shaped element has light-refracting structures.

[0012] According to the invention, the light-refracting structures of the secondary optics are prism-like structures, in particular pyramid-shaped prism structures. Such structures are already known and serve to control the light distribution of a beam entering the input side and to reduce glare. It has now been shown that the glare-reducing efficiency of such scattering structures is highest when the incident light hits the secondary optics in a nearly ideally focused manner. This task is achieved according to the invention by utilizing the primary optics, which, with the aid of the pot-like reflectors, redirects the light emitted by the LEDs or LED clusters into nearly perfectly parallel light beams.This allows for extremely efficient control of the light output, ensuring the desired glare-free light distribution, especially with high light levels and narrow light exit openings.

[0013] Preferably, the pot-shaped reflectors have light exit openings located in a common plane, with the secondary optics then being arranged at a distance from this plane, in particular at a distance of approximately 4 mm. This measure ensures that no individual beams impinge on the light entry side of the secondary optics. Instead, an overlap occurs in the transition area between two adjacent pot-shaped reflectors, reducing or compensating for differences in luminance. This thus homogenizes the overall appearance of the light-emitting area of ​​the luminaire.

[0014] According to the invention, the pot reflectors have sidewall regions that, viewed in the longitudinal direction, have a parabolic shape, with the LEDs or LED clusters then being arranged at the focal point of this parabolic shape. In this case, the parabolic shape ensures particularly efficient light bundling, which – as explained above – is important with regard to the functioning of the secondary optics.

[0015] In principle, a corresponding parabolic shape for the pot-shaped reflectors would also be advantageous in the transverse direction of the luminaire. However, since the distance between the individual LEDs or LED clusters should be relatively small to achieve a high light output, and the pot-shaped reflectors are therefore positioned close together, a continuous parabolic shape of the reflector walls would result in an overlap between two adjacent reflectors. To avoid this and still enable a compact arrangement of the LED light sources, the invention therefore provides that the side wall regions of the pot-shaped reflectors extending transversely to the longitudinal direction of the luminaire transition into inclined, flat side surfaces.

[0016] The pot-shaped reflectors each have light entry openings, with each light entry opening assigned to an LED or LED cluster. As already mentioned, in the case of parabolic reflector walls, the LEDs or LED clusters are located at the focal point of the parabola.

[0017] To further enhance the appearance of the luminaire, an additional light-diffusing element, in particular a diffusing film, can be arranged between the primary optics and the secondary optics. This can, for example, be arranged on the light entry side of the secondary optics, resting on the latter.

[0018] The luminaire according to the present invention preferably has an elongated housing forming a narrow light exit opening, wherein the light exit opening is completely closed by the secondary optics or a translucent cover adjacent to the secondary optics. All light exiting the luminaire is thus influenced in the desired manner by the previously described inventive measures, so that, with a preferred width of the light exit opening of approximately 3 cm, a high quantity of high-quality light can still be emitted.

[0019] The invention will be explained in more detail below with reference to the accompanying drawings. They show: Figure 1 shows an embodiment of a luminaire according to the invention in a perspective view; Figure 2 shows a sectional view of the luminaire according to the invention in the transverse direction; Figure 3 shows a sectional view of the luminaire according to the invention in the longitudinal direction; Figures 4 and 5 show two perspective views of the component forming the primary optics; Figure 6a shows the influence of the primary optics on the light emitted by the LEDs; Figure 6b shows the light distribution achievable by the primary optics; Figure 7a shows the further influence of the light on the light by the secondary optics, and Figure 7b shows the distribution of the light ultimately emitted by the luminaire according to the invention.

[0020] The inventive concept is explained below using an elongated individual luminaire, which is intended, for example, to illuminate an office workplace and is intended to emit light at high intensity, yet homogeneously, across a narrow light-emitting surface in such a way that glare is reduced to achieve a so-called UGR value of less than 19. This UGR value (Unified Glare Rating) describes the psychological glare effect of a lighting system in a specific viewing position, whereby the UGR value of 19 is decisive for office spaces and should not be exceeded in order to ensure glare-free work at a computer workstation.

[0021] However, it should be noted that the concept for influencing light described below is not limited to the individual luminaire shown and corresponding applications, but can be used whenever high-intensity light is to be emitted homogeneously over a relatively narrow area in such a way that the risk of glare to the viewer is largely avoided. In particular, the optical concept described below would also be suitable, for example, for so-called elongated light strips, which form narrow, elongated strips in a wall or ceiling area of ​​a room, emitting light homogeneously across their entire length.

[0022] The Figure 1 in perspective view and in the Figures 2 and 3The luminaire 100 shown in section therefore initially has an elongated housing 50, which is essentially formed by an elongated profile part 55. This profile part 55, which in the illustrated embodiment is designed for attachment to a support rail, but could equally well be mounted on or in the ceiling of a room or suspended, has a C- or H-shaped cross-section and thus forms an elongated receiving space for storing the components responsible for light generation and light emission. Furthermore, an operating device 110 is arranged on the upper side of the profile part 55, which converts the supply voltage made available to the luminaire 100 into a suitable operating voltage for the lamps.

[0023] The profile part 55 consists, for example, of a corresponding extruded profile, for example made of aluminum, although other materials are also conceivable. On the underside of the housing 50, an elongated light exit opening 51 is defined by the two side walls 52 of the profile part 55, through which the light of the luminaire 100 is emitted. As already mentioned, it is desired that light be emitted evenly and homogeneously across the entire length and width of the light exit opening 51, whereby the width of the light exit opening 51 should be as narrow as possible, preferably on the order of approximately 3 cm. Nevertheless, intensive light with a lumen output of approximately 2000 lm / m should be emitted.

[0024] The luminaire 100 according to the present invention uses LEDs 60 as light sources, which are positioned in the longitudinal direction of the housing 50 on one or more LED boards 65 arranged one behind the other. In the following, it is assumed that these are individual LEDs 60. However, it would also be conceivable to use LED clusters consisting of multiple LEDs instead of these individual LEDs 60. If these are designed to emit light in different colors or color temperatures, it would be possible to influence the color or color temperature of the overall light emitted by the luminaire 100 by individually controlling the various LEDs. The LED board(s) 65 is / are arranged on a web 56 extending essentially horizontally through the profile part 55.

[0025] The inventive influencing of the light generated by the LEDs 60 is achieved with the aid of an optical system 10, the structure and function of which will be explained in more detail below. The optical system 10 essentially consists of two components: a primary optic 20, which is directly associated with the LEDs 60, and a secondary optic 30 located in the region of the light exit opening 51 of the luminaire 100.

[0026] In the following, the design and operation of the primary optics 20 will be explained. This is a component which can also be individually installed in the Figures 4 and 5is shown and forms a plurality of pot-shaped reflectors 25 arranged one behind the other in the longitudinal direction of the luminaire 100, which are intended to bundle the light emitted by the LEDs 60 in a first step. This primary optic 20 is preferably formed by an injection-molded plastic part, which is then coated or mirrored with a correspondingly highly reflective coating. Several of the pot-shaped reflectors 25, preferably all of them, are combined in one piece to form the illustrated component.

[0027] The primary optics 20 is designed in such a way that each LED 60 (or each LED cluster) is assigned a reflector cup 25, which is intended to bundle the light of this LED 60 accordingly. The reflector cup 25 has a light inlet opening 26 on its side facing the LEDs 60, in which the LED 60 is positioned or into which the LED 60 protrudes. Starting from this light inlet opening 26, the side walls of the reflector cup 25 diverge downwards, thus widening in the light emission direction of the luminaire 100, wherein they each enclose a corresponding light outlet opening 27 at the lower end. From the lateral regions of these light outlet openings 27 extend - as can be seen particularly in the Figure 2 , 4 and 5can be seen - lateral webs 21 with locking arms 22 arranged thereon, via which locking with corresponding projections of the profile part 55 forming the housing 50 takes place. In this way, a simple, tool-free fastening of the primary optics 20 in the luminaire housing 50 is possible.

[0028] The webs 21 are inclined outward in such a way that they do not fulfill any significant function for light emission. At most, rays reflected or scattered on the surface of the secondary optics 30, described in more detail below, could be additionally reflected by these surfaces. However, the actual light influence occurs, as explained below, through the side walls of the pot-shaped reflectors 25.

[0029] The function of the pot reflectors 25 is to focus the light emitted by the LEDs 60 as tightly as possible, in particular such that the resulting beam has a full width at half maximum (FWHM) of less than 10°. A correspondingly strong focusing of the light can be achieved, for example, by the highly reflective side walls of the pot reflectors 25 being parabolic in shape, i.e., following a parabolic shape, with the LEDs 60 arranged at the focal point of the parabola.

[0030] In the primary optics 20 of the luminaire 100 according to the invention, it is accordingly provided that in particular the lateral wall regions 25a of the pot reflectors, seen in relation to the longitudinal direction of the luminaire 100, have this parabolic shape and, with respect to the central axis I (see Figure 2 ) are rotationally symmetrical.

[0031] Ideally, the pot reflectors 25 should be rotationally symmetrical over their entire circumference. However, as mentioned at the beginning, a relatively high amount of light should be generated and emitted in the present luminaire 100, which results in the LEDs 60 or LED clusters being arranged one behind the other in the longitudinal direction of the luminaire 100 at a relatively short distance. This short distance between the LEDs 60 means that in the case of complete rotational symmetry of the pot reflectors 25, they would overlap accordingly. To avoid this, it is therefore provided that in a direction transverse to the longitudinal direction of the luminaire 100, the corresponding side wall regions 25b transition from the parabolic shape to a planar shape, as is particularly the case in Figure 3 is recognizable.

[0032] The pot reflectors 25 are thus formed from two different side wall areas 25a, 25b, on the one hand the lateral wall areas 25a in comparison to the longitudinal center plane of the lamp 100, which are completely or over their entire height parabolic and rotationally symmetrical with respect to the axis I, and on the other hand the wall areas 25b extending transversely thereto, which merge into a planar form and thereby Figure 3 recognizable V-shaped transverse lamellar structures.

[0033] The effect of the primary optics 20 on the light emitted by the associated LEDs 60 is shown in the Figures 6a and 6b shown, where Figure 6a shows the simulated beam path of the LED light while Figure 6b The resulting light distribution curve is shown. The ray path in Figure 6ashows that the light initially emitted by the LEDs 60 over a wide angular range is reflected by the side wall areas 25a and 25b of the pot reflectors 25 in such a way that it is directed downwards as an almost perfectly parallelized beam. This is also shown by the corresponding light distribution curve in Figure 6b , which reveals an extremely strong bundling of the light with an extremely narrow half-width. It is also evident that the planar design of the transversely oriented sidewall regions 25b has no negative effects on the light bundling, and the light rays are also efficiently parallelized in the longitudinal direction of the luminaire 100.

[0034] The light bundled in the manner described above is then further modified, in particular expanded, by the aforementioned secondary optics 30 before being emitted via the light emission opening 51 of the luminaire 100. This secondary optics 30 is a microprism plate made of a transparent material and having pyramid-like microprism structures 35 on its surface facing away from the LEDs 60. The angle of inclination of the individual pyramids is in the range of 111°. Such structures are already known and are widely used in lighting technology. They serve to slightly direct the incident light in order to adapt the light output to a desired light distribution and glare control.

[0035] For the luminaire 100 according to the invention, it is now essential that the effectiveness of the secondary optics 30 is improved the more strongly the light incident on it is focused. This is the reason why the pot reflectors 25 of the primary optics 20 are designed, as described above, to extremely strongly focus the light emitted by the LEDs 60.

[0036] The incident light can then be directed in a defined manner by the prism structures 35, as shown in the Figures 7a and 7b These figures show, in an analogous manner to the Figures 6a and 6bthe ray path of the light and the ultimately resulting light distribution. It can be seen that the pyramid-shaped prism structures 35 expand the initially highly parallelized light again and emit it over a desired angular range, which is selected such that a half-width of approximately 60° is not exceeded, thus meeting the requirement for a UGR value below 19.

[0037] However, this controlled expansion is only possible due to the light beam tightly focused by the primary optics 20. The combination of the primary optics 20 and the secondary optics 35 thus enables a very high amount of light to be emitted through the light exit opening 51 of the luminaire 100, while still remaining consistent with the desired light distribution, particularly a light distribution that can be used to illuminate office workstations.

[0038] As can also be seen from the figures, the light exit openings 27 of the pot reflectors 25, which lie in a common plane E, have a certain distance d from the surface O of the secondary optics 30 (see Figure 2 This distance d is necessary to prevent the beams generated by the pot reflectors 25 from impinging separately on the secondary optics 30. Instead, light can now also impinge on areas of the secondary optics 30 that are not directly below the opening 27 of a pot reflector 25. The distance d between the two optical components 20 and 30, which is preferably in the range of approximately 4 mm, ensures that light is emitted homogeneously over the entire length of the luminaire 100. This means that the light exit opening 51 appears essentially uniformly bright over its entire length and width.

[0039] In the illustrated embodiment, the secondary optics 30 does not form the final light-emitting element of the luminaire 100. Instead, a flat cover 40 made of a transparent material is provided, which is arranged in the region of the light-emitting opening 51 of the housing 50 and on which the secondary optics 30 is mounted. However, this cover 40 is not important for the light emission, since it is not intended to significantly influence the light rays.

[0040] Furthermore, it can be provided that a diffusing film or generally a light-diffusing element 45 is positioned on the upper side of the secondary optics 30 facing the LEDs 60. This is intended to prevent a direct view into the luminaire 100, so that the individual LEDs 60 or LED clusters as well as the individual pot reflectors 25 are not visible to an observer. However, just like the cover 40, this only slightly diffusing film 45 should not significantly influence the previously explained function of the primary optics 20 and the secondary optics 30.

[0041] Overall, the optical concept according to the invention opens up the possibility of creating luminaires with extremely narrow light exit openings (for example in the range of only about 3 cm), which nevertheless emit a very high amount of light homogeneously and glare-free.

Claims

1. Luminaire (100), comprising: • an elongate light source which is formed by a plurality of LEDs (60) or LED clusters arranged one behind the other in the longitudinal direction, • a primary optical system (20) which is assigned to the light source and is formed by a plurality of pot-like reflectors (25) which are arranged one behind the other in the longitudinal direction, and each widen in a divergent manner from the light source in a light emission direction of the luminaire (100), • a secondary optical system (30) which follows the primary optical system (20) in the light emission direction and is formed by a plate-shaped element made of a transparent material, the element having light-refracting structures (35), characterized in that the light-refracting structures (35) are prisms, in particular pyramid-shaped prisms, and the pot reflectors (25) having parabolically shaped side wall regions (25a) when viewed in the longitudinal direction, each of the pot reflectors (25) having a central axis (I), the parabolically shaped side wall regions (25a) being rotationally symmetrical with respect to the central axis (I), and the LEDs (60) each being arranged at the focal point of the parabola, and the pot reflectors (25) having side wall regions (25b) inclined in a direction perpendicular to the longitudinal direction.

2. Luminaire according to claim 1, characterized in that the pot-like reflectors (25) have light outlet openings (27) which lie in a common plane (E), the secondary optical system (30) being arranged at a distance (d) from this plane (E), in particular at a distance (d) of approximately 4 mm.

3. Luminaire according to any of the preceding claims, characterized in that the pot-like reflectors (25) have light inlet openings (26), each light inlet opening (26) being assigned to an LED (60) or an LED cluster.

4. Luminaire according to any of the preceding claims, characterized in that a plurality of pot-like reflectors (25), preferably all of them, are combined to form a one-piece component, in particular an injection-molded plastics part.

5. Luminaire according to any of the preceding claims, characterized in that a light-scattering element (45), in particular a scattering film, is arranged between the primary optical system (20) and the secondary optical system (30).

6. Luminaire according to any of the preceding claims, further comprising an elongate housing (50) which forms a light outlet opening (51), wherein the light outlet opening (51) is completely closed by the secondary optical system (30) or a translucent cover (40) resting against the secondary optical system (30).

7. Luminaire according to claim 6, characterized in that the light outlet opening (51) has a width of approximately 3 cm.

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