Luminaire and lighting system

Abstract

This invention relates to a lighting fixture comprising: a stack of parallel transparent light-transmitting plates, including a light guide plate and an optical plate. The light guide plate includes first and second main light-guiding surfaces and circumferential edge walls, and is edge-illuminated by LEDs. At least one main light-guiding surface is equipped with an external optical coupling structure, the external optical coupling structure including external optical coupling elements arranged at a first spacing P1. The optical plate includes first and second main optical surfaces, the first main optical surface facing a second main light guide surface, and only one of the first and second main optical surfaces is provided with an optical structure including optical elements arranged at a second spacing P2. The second main light guide surface and the first main optical surface are spaced apart by a spacing S in a direction perpendicular to the main light guide surfaces, wherein S is in the range of 0-12 mm. P1 and P2 are in the range of 1-7 mm, and the ratio between P1 and P2 is in the range of 0.5-2.

Description

Technical Field

[0001] The present invention relates to a lamp and a lighting system comprising a plurality of said lamps. Background Technology

[0002] In offices, luminaires must meet office compliance requirements. For example, office compliance indicators prioritize characteristics such as glare, efficiency, and comfort, second only to other specifications. Typically, glare is indicated by a Uniform Glare Ratio (UGR) and an L65 value. The UGR value for offices should generally be 19 or less, and the L65 value is the maximum luminance of the luminaire component directly visible at a screen angle >= 65 degrees (perpendicular to the office ceiling). For more details, see European standards EN12464-1 and CIE117-1995. Luminaires are also expected / required to provide a minimum level of illumination with a specified minimum efficiency, a characteristic defined by the Light Output Ratio (LOR).

[0003] For example, in offices, lighting comfort is becoming increasingly important. Lighting comfort involves the minimum level of illumination, as well as the level of glare and distraction from the luminous portion of the fixture, and preferably should be as low as possible. To this end, known luminaires providing general ambient lighting in offices are mounted on the ceiling and equipped with optics and screens to evenly distribute the generated light, guide it in a specific direction, and protect people from direct view of the high-brightness portion of the fixture within a specific angular range. Typically, these optics include optical panels with an optical structure comprising a pattern of optical elements. It appears that, for known luminaires, the combination of all the above requirements cannot be achieved while simultaneously providing sufficiently comfortable lighting. Furthermore, known luminaires have the disadvantages that their optical panels are relatively expensive, difficult to manufacture, and often cause distraction for people walking under them. Therefore, it is desirable to manufacture an efficient office luminaire that is cost-effective, meets standard office compliance requirements, and provides comfortable lighting.

[0004] US20100026703 discloses a light-emitting component including a light source configured to illuminate a stack of parallel-arranged light guide plates and optical plates. Summary of the Invention

[0005] The object of this invention is to provide a lamp of the type described in the opening paragraph, wherein at least one disadvantage is overcome. To this end, the lamp of this invention comprises:

[0006] The stacking of parallel light-transmitting plates, including light guide plates and optical plates,

[0007] The light guide plate includes first and second main light guide surfaces connected by circumferential edge walls, and is edge-illuminated by LEDs during operation. At least one of the main light guide surfaces is equipped with an external coupling structure, which includes external coupling elements arranged at a substantially constant first spacing P1 in the x-direction and at a substantially constant first spacing P1a in the y-direction perpendicular to the x-direction.

[0008] The optical plate includes first and second main optical surfaces, the first main optical surface facing the second main light guide surface, and only one of the first and second main optical surfaces is provided with an optical structure including optical elements arranged at a substantially constant second spacing P2.

[0009] The second main optical guide surface and the first main optical surface are spaced apart by a distance S in a direction perpendicular to the main optical guide surface, wherein S is in the range of 0-25 mm (preferably 5-9 mm).

[0010] Wherein P1, P1a and P2 are in the range of 1-7 mm (preferably 1.5-6 mm), and the ratio of P1 and P1a to P2 is in the range of 0.5-2 (preferably 0.8-1.25), that is, 0.5≤P1 / P2, P1a / P2≤2, preferably 0.8≤P1 / P2, P1a / P2≤1.25, and more preferably P1 / P2, P1a / P2 are substantially equal (i.e. P1 / P2, P1a / P2=1).

[0011] The light guide is also referred to as the first optical plate or simply the first stage, and the optical plate is also referred to as the second optical plate or simply the second stage. The first spacing P1 (also called P1x) is related to both the first spacing P1 (or P1x) in the x-direction and the first spacing P1a (also called P1y) in the y-direction perpendicular to the x-direction. P1 can be different from or equal to P1a. In the description, the discussion refers only to P1, which can be considered to include both P1a and P11.

[0012] The inventors have discovered that luminaires with the construction and arrangement of the plates and optical elements as described above provide an attractive 3D moiré effect. This moiré effect is achieved due to the stacked arrangement of the external coupling structure and the optical structure (i.e., effectively a superposition of the structures), and due to the mutual arrangement of the external coupling elements of the external coupling structure and the optical elements of the optical structure. The moiré effect can be controlled by variations in the arrangement (e.g., by variations in the pitch S) and by variations in the pitch ratio P1 / P2. As a result, the luminaire can be given an attractive appearance while simultaneously exhibiting an acceptablely low level of disturbance to people. Specific construction features further allow the height of the luminaire (measured, for example, along an axis perpendicular to the second main light guide surface) to be limited to a maximum of 20 mm, thereby making the luminaire even more attractive and, in principle, suitable for use as recessed, surface-mounted, or suspended luminaires. In the context of this invention, the expression "substantially constant" means a range of ±10% around a specific value.

[0013] It appears that features, particularly the similarity between the external coupling structure of the light guide plate and the optical structure of the optical plate, determine the attractiveness of the obtained moiré effect. This similarity typically involves the arrangement of the corresponding external coupling elements and optical elements, as well as their respective spacings P1 and P2, which should not deviate too much from each other, i.e., 0.5 ≤ P1 / P2 ≤ 2. Furthermore, it appears that the spacing between the external coupling structure and the optical structure determines the depth and magnitude of the observed moiré effect. By varying these features within a given range, the intensity of the obtained moiré effect can be tuned.

[0014] Preferably, the first-level structures (external coupling elements) are spaced apart from each other at a certain distance; otherwise, the desired moiré effect will eventually disappear. The second-level structures are preferably close to each other to best control glare. For the second level, all structures are closely aligned so that they provide the optimal moiré effect. Furthermore, if any structure becomes too shallow, the moiré effect will eventually be invisible to the human eye. Typically, the distance S between the second primary light guide surface and the first primary optical surface is related to the first distance P1 between the external coupling elements on the light guide surface, i.e., 0.5*P1≤S≤4*P1, preferably 1*P1≤S≤2*P1. Typically, the light guide and / or optical plate are made of transparent materials, such as polycarbonate (PC) or polymethyl methacrylate (PMMA); however, other transparent materials are also possible, such as polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP).

[0015] The luminaire may have the following characteristics: the external coupling elements and optical elements are arranged in a 2D arrangement according to at least one of the following arrangements: an octagonal arrangement (i.e., each element is surrounded by eight adjacent elements, generally / preferably all at the same distance), a hexagonal arrangement (i.e., each element is surrounded by six adjacent elements, generally / preferably all at the same distance), a square or rectangular arrangement (cube, i.e., each element has four adjacent elements, preferably all at the same distance), or a triangular arrangement (i.e., all elements are surrounded by three adjacent elements, preferably all at the same distance). This is a convenient way to arrange the external coupling elements and optical elements. Combinations of these arrangements are possible, such as combinations of hexagonal and triangular arrangements and combinations of octagonal and square arrangements. These arrangements are preferred because they provide an improved 3D effect in terms of attractiveness and because they can be arranged to form a closed tessellated surface. Furthermore, the transparent plate with such an arrangement of external coupling elements or optical elements can be relatively easily manufactured via extrusion and embossing processes. On the optical plate, the optical elements are preferably sized such that they contact each other and form a closed surface to obtain a further improved beam shaping effect, since no light can propagate through the optical plate without being shaped by the optical elements.

[0016] The luminaire may have the following characteristics: the arrangement of the external coupling elements and the arrangement of the optical elements have relative rotational positions about an axis A perpendicular to the second main light guide surface; for a hexagonal arrangement of the external coupling elements and the optical elements, they rotate relative to each other at an angle α of approximately 30 degrees; for a square / rectangular arrangement of the external coupling elements and the optical elements, they rotate relative to each other at an angle α of approximately 45 degrees; and for a triangular arrangement of the external coupling elements and the optical elements, they rotate relative to each other at an angle α of approximately 90 degrees. It appears that, in addition to the foregoing features, the characteristics of the relative rotational positions of the arrangements largely determine the attractiveness of the obtained moiré effect.

[0017] In particular, mutually oriented arrangements within a given angular range of various configurations provide a highly desirable 3D moiré effect. The optimal results for the desired moiré effect are obtained when both the optical elements and the light guide elements are arranged in a hexagonal configuration and rotated relative to each other at an angle α of 30 degrees. However, the external coupling element and the optical element can also be arranged in different configurations, for example, the external coupling element in a hexagonal configuration and the optical element in a square configuration, or vice versa. In the context of this invention, the expression "substantially" means a range of less than ±5% (e.g., 2%) around a specific angle.

[0018] Expressed as a formula, it can be summarized as follows:

[0019] The rotation angle α is (360° / side) * 0.5. For various pyramid shapes, the following formula applies:

[0020] Triangle → Sides = 3 → Rotation angle α is 120 * 0.5 = 60°;

[0021] Square → Sides = 4 → Rotation angle α is 90 * 0.5 = 45°;

[0022] Hexagon → Sides = 6 → Rotation angle is 60 * 0.5 = 30°;

[0023] Hexagons combined with triangles, such as the BWF Diamond, show in experiments that although the triangle requires a rotation of α=60°, a good 3D effect can be obtained with a rotation of α=30°.

[0024] Octagon → Sides = 8 → Rotation angle α is 45 * 0.5 = 22.5°. However, if octagonal elements are used, the tessellation surface is always a combination of octagonal elements and rectangular / square elements. For rectangular / square elements, a rotation angle α of 45° is required, but good results are still achieved with α = 22.5°. Therefore, to further improve the moiré effect, not only spacing but also arrangement is important. Preferably, for optimal 3D effect without dispersing the moiré effect, the arrangement of both the first and second levels needs to be similar or identical, but this arrangement should rotate relative to each other in a manner that is different from their phase (i.e., rotates relative to each other), as indicated above.

[0025] The luminaire may have the following characteristics: the external coupling structure is disposed only on the first main light guide surface, and the optical structure is disposed only on the second main optical surface. The inventors have found that luminaires with these specific construction features are attractive, provide comfortable illumination, and can meet office lighting requirements regarding UGR, L65, and LOR. The external coupling element and the optical element can be serrated or protruding. However, it appears that the comfort of illumination is further improved when the optical element is protruding, and either the external coupling element is serrated and disposed on the first main light guide surface, or the external coupling element is protruding and disposed on the second main light guide surface. However, serrated external coupling elements are preferred over protruding ones because it is easier and more precise to manufacture a light guide plate with serrated external coupling elements than to manufacture one with protruding external coupling elements. Alternatively or additionally, the external coupling structure may include external coupling elements embodied as virtually flat elements, i.e., non-protruding or non-serrated elements (e.g., printed dots or etched dots) on either side or both sides of the light guide plate.

[0026] The luminaire can have the following characteristics: the external coupling element and the optical element have a conical shape, preferably a circular cone or a 4-faceted or 6-faceted cone. It appears that the combination of parameters (such as UGR, L65, and LOR) is further improved. This positive effect is further enhanced if it is combined with the optional characteristics of the optical element's cone having an apex angle in the range of 100-120 degrees (preferably 103-110 degrees) and the external coupling element's cone having an apex angle in the range of 60-140 degrees (preferably 70-90 degrees). It appears that the UGR, L65, and LOR parameters can be changed and controlled by varying the conical shape and the characteristics of the apex angle. This variation can be obtained substantially independently of the resulting moiré effect. The pyramid or cone can also be embodied as a truncated pyramid or cone, with the virtual apex formed having a virtual vertex angle in the range of 60-140 degrees (preferably 70-90 degrees) by virtually extending the facets or circumferential walls of the pyramid or cone (also referred to as the sidewalls of the pyramid or cone). Preferably, the truncated pyramid or cone is embodied such that the truncated portion is slightly rounded, i.e., the circle has a radius R of, for example, about 0.5 mm. This allows the light guide plate with this external coupling structure to be easily and inexpensively manufactured by extrusion, i.e., at about 25% of the cost of the known Jungbecker MLO plate, which requires thermoforming.

[0027] In short, the moiré effect obtained by the luminaire is mainly determined by the mutual spacing between the light guide plate and the optical plate, as well as by the (mutual) arrangement of the external coupling element and the optical element, while the UGR, L65 and LOR obtained by the luminaire are mainly determined by the shape of both the external coupling element and the optical element.

[0028] The luminaire may have the following features: a transparent plate has a rectangular shape with two opposing short edge walls and two opposing long edge walls as the perimeter of the rectangle, wherein LEDs are arranged at at least one long edge wall. In this luminaire construction with LEDs arranged along the long edge walls, the maximum distance light travels into the light guide is essentially only along the length of the short edge walls. This makes it easier to control the uniform light output emitted from the light guide optical plate, and thus control the uniformity of light output across the entire surface of the optical plate. When the luminaire has an optional feature, the control and the resulting uniformity of light output are further improved. This optional feature is that the LEDs are arranged at the two long edge walls, and wherein the external coupling element has a protruding size and / or serrated depth that gradually increases in a direction transverse to the long edge walls along essentially the entire distance from the long edge wall to the (long) centerline of the light guide plate. The increase in the size and / or depth of the external coupling element with increasing distance from the LEDs improves the uniformity of external coupling of light from the light guide.

[0029] The luminaire may feature a diffuser between the light guide plate and the optical plate, with a diffuser intensity in the range of 10-30%. Because light coupling from the light guide primarily occurs only at the location of the external coupling element, the luminous surface of the luminaire (i.e., the optical plate) may exhibit speckles, which are generally considered undesirable and can interfere with the desired moiré effect. The diffuser is provided to reduce the risk of speckles and distortion due to the moiré effect. Both speckles and the moiré effect can be adjusted by the degree of diffuser and the distance of the diffuser from the optical plate; for example, the closer the diffuser is to the optical plate, the stronger the diffuser effect, and therefore the fewer speckles, and the less (undisturbed) the moiré effect, i.e., the moiré effect will be smoothed out.

[0030] The luminaire may have the following characteristics: it includes a reflector facing and extending parallel to the first main light guide surface, the reflector preferably being a diffuse reflector. In practice, a portion of the light coupled from outside the light guide plate into the optical plate is always reflected back as back-reflected light from the optical plate to the light guide plate, and passes through the light guide plate because the light is at an angle outside the TIR angle of the light guide plate. To compensate for this loss of back-reflected light, the reflector is provided for recycling the back-reflected light. This not only has the advantage of improving the light output efficiency (LOR) of the luminaire, but also achieves uniform, relatively low background illumination superimposed on the luminous moiré effect. Preferably, the reflector is not in optical contact with the light guide plate, because this means a (partial) loss of the TIR properties of the LG plate, and thus results in lower luminaire efficiency, since some light is lost with each reflection at the reflective layer. In the case of TIR, this light loss with each reflection does not occur. However, from the perspective of reducing the cost of the luminaire, optical contact between the reflective layer and the light guide plate is acceptable, but at the cost of some loss of LOR.

[0031] The luminaire may have the following characteristics: the plate is an extruded plate made of a transparent material (such as PMMA, PC, and / or PE). These materials are conventional and suitable materials commonly used for light guide plates and optical plates.

[0032] The luminaire may have the following characteristics: a light guide plate has a thickness Dl, and an LED has a light-emitting surface with a height Hl in a direction perpendicular to the first main light guide surface, where 0.3 ≤ Hl / Dl ≤ 0.7. This feature results in effective light coupling into the light guide plate because it cancels out the fact that a relatively large portion of the light emitted by the LED is not guided to the circumferential wall of the light guide plate; that is, there is little to no light loss when light from the LED is coupled into the light guide via the edge of the light guide, and the light coupling occurs within a desired angular range relative to the main surface of the light guide for TIR in the light guide. The luminaire may also have the following characteristics: the depth or height Doe of the external coupling element is in the range of 10-70% of the thickness Dl of the light guide plate. DH may be constant throughout the light guide, or it may gradually increase in the direction from the long edge wall to the (long) centerline of the light guide plate. With a depth (or height) of at least 10%, sufficient light propagating inside the light guide is illuminated on the external coupling element, while the upper limit of 70% results in sufficient light propagating to the external coupling element furthest from the light source (LED) and being externally coupled by the external coupling element furthest from the light source (LED).

[0033] The luminaire may have the following characteristics: no external coupling elements are present in the region of the first main light guide surface along the edge wall of the light guide plate (where LEDs are arranged), said region being between L1 and L2, wherein:

[0034]

[0035] Where D = the distance between the first main light guide surface and the LED in the direction perpendicular to the first main light guide surface;

[0036] Dl = the thickness of the light guide plate in the direction perpendicular to the surface of the first main light guide; and

[0037] n = the refractive index of the material of the light guide plate.

[0038] In offices, luminaires that meet office compliance requirements are preferred, such as the maximum UGR and maximum L65 for specific areas and emitting lumens. Office compliance indicates low glare, high comfort, and a variety of other specifications (to make it comprehensive). The goal is to manufacture a new, efficient office luminaire that is cost-effective, meets standard office compliance requirements, and, where possible, exceeds some. Additionally, the luminaire should be aesthetically pleasing, and its height is preferably limited to within 20 mm, allowing it to be used as a recessed, surface-mount, or pendant luminaire. It appears that bright spots appear at certain locations on the surface of the externally coupled element of the first main light guide, which is detrimental to meeting the UGR and L65 office compliance requirements. These bright spots depend on the presence of the externally coupled element in a critical region, which appears to be between L1 and L2, indicating distances from the incident surface of the light guide. Before L1, light from an LED source located on the edge wall (or the incident surface of the light guide) cannot reach the externally coupled element due to refraction. Beyond L2, the virtual image of the LED light source can no longer be formed, thus avoiding bright spots. However, if the first reachable external coupling element extends too far beyond L2, a dark gap occurs. Therefore, the optimal position of the first reachable external coupling element is at L2. Accordingly, this feature itself can be considered an independent invention.

[0039] The present invention also relates to a lighting system comprising at least two luminaires according to the present invention and as described above, wherein the luminaires are aligned with each other and / or form a closed inlaid surface, wall, and / or ceiling. The alignment of the luminaires and / or the closed inlaid surface formed by multiple luminaires provides an attractive, coherent, and immersive 3D effect.

[0040] In short, this invention relates to achieving an attractive moiré pattern through optical coupling between an external coupling structure of a light guide and the optical elements of an optical plate, while also satisfying a Uniform Glare Ratio (UGR), which for offices is typically 19 or less, an L65 value (the maximum luminance of the luminaire component directly visible at a screen angle >= 65 degrees (perpendicular to the office ceiling), and the luminaire also providing a minimum level of illumination with a specified minimum efficiency, a characteristic defined by the Light Output Ratio (LOR). For this purpose, the following parameters are typically used to obtain the desired moiré effect:

[0041] Changes in the mutual orientation of the external coupling structure and the optical structure;

[0042] Variations in the shape and size of external coupling elements and optical elements, such as cones, pyramids, inverted tops, round tops, pointed tops, etc.;

[0043] Variations in serrated or protruding shape, i.e., the optical element is serrated or protruding and the external coupling element is serrated;

[0044] Variations in the arrangement of external coupling elements and optical elements, such as hexagons, triangles, and squares;

[0045] Variations in the spacing between external coupling elements and optical elements, as well as variations in the spacing of external coupling elements within a single external coupling structure. Attached Figure Description

[0046] To better understand the invention and to more clearly illustrate how it can be practiced, reference will now be made to the accompanying drawings by way of example only, in which:

[0047] Figures 1A-1D The images show bottom views of the light fixture (with LEDs on both long sides). Figure 1A A partial perspective section of the lamp fixture construction according to the first embodiment of the present invention ( Figure 1B ), partial cross-sections of two other embodiments of the lamps according to the present invention ( Figure 1C + Figure 1D );

[0048] Figures 2A-2D Various arrangements of optical structures and / or external coupling structures are shown;

[0049] Figures 3A-3E This illustrates various moiré effects obtained through different combinations of external coupling structures and optical elements;

[0050] Figures 4A-4B Details of examples of external coupling elements for optical components are shown respectively;

[0051] Figures 5A-5BA perspective view of a light guide plate with an external coupling structure is shown, along with details of an example arrangement of the external coupling elements;

[0052] Figures 6A-6D The beam profiles obtained by some different hexagon-hexagon combinations for the external coupling structure and optical elements are shown, with variations made in the sawtooth external coupling structure of the light guide (first stage);

[0053] Figure 7 The optimal location of the external coupling element closest to the edge wall of the light guide plate is shown; and

[0054] Figure 8 A lighting system comprising an aligned arrangement of luminaires according to the invention is shown. Detailed Implementation

[0055] The invention will be described with reference to the figures. It should be understood that while the detailed description and specific examples indicate exemplary embodiments of the apparatus, systems, and methods, they are intended for illustrative purposes only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems, and methods of this disclosure will become better understood from the following description, the appended claims, and the accompanying drawings. It should be understood that the figures are merely schematic and not necessarily drawn to scale; sometimes dimensions may be exaggerated for ease of interpretation. It should also be understood that throughout the figures, the same reference numerals are used to indicate the same or similar parts.

[0056] Figure 1A and Figure 1B A bottom view and a partial perspective view of the main structure of the lamp 1 according to the present invention are shown respectively. The lamp 1 includes a square housing 3 housing a stack 5 of parallel transparent light-transmitting plates, the stack 5 including a light guide plate 7 and an optical plate 9, which, as in... Figure 1BThis is particularly evident in a partial cross-section of the luminaire shown. The light guide plate 7 is edge-illuminated by two LED arrays 11 mounted on opposite sidewalls 13 of the housing. An external coupling structure 17 is provided on the first main light guide surface 15 of the light guide plate 7, comprising a grid of serrated conical external coupling elements 19 spaced at regular intervals P1. During operation of the LEDs 11, light generated by the LEDs 11 is coupled into the light guide plate 7 and redirected towards the optical plate 9 by the external coupling elements 19. The redirected light propagates into the optical plate 9 via the second main light guide surface 21 of the light guide plate 7 and via the first main optical surface 23. Finally, before being emitted to the outside, the light is shaped by an optical structure 24 of optical elements 25 provided on the second main optical plate surface 27 of the optical plate 9. The optical elements 25 are protruding square pyramids arranged in a grid at regular intervals P2 on the second main optical plate surface 27. Here, the intervals P1 and P2 are approximately the same, approximately 4 mm. The second main light guide surface 21 and the first main optical surface 23 are spaced apart by a distance S in a direction perpendicular to the second main light guide surface 21, where S is approximately 5 mm. As shown, the grid of the external coupling element 19 and the grid of the optical element 25 are rotated about 45° relative to each other about an axis A perpendicular to the main surfaces of the light guide plate 7 and the optical plate 9.

[0057] Figure 1C A partial cross-section of a first basic embodiment of a luminaire 1 according to the present invention is shown. The luminaire 1 includes a housing 3 having a back side 4 and sidewalls 13. An array of LEDs 11 arranged on a PCB 12 is mounted on the housing 3 in a side-illumination configuration with an edge 8 having a light guide plate 7. The LEDs 11 are configured to emit LED light 12 into the light guide plate 7 during operation. The light guide plate 7 has a first main light guide surface 15 facing the back side 4 of the housing 3, thereby creating a space 31. The first main light guide surface 15 is equipped with a grid of external coupling elements 19 arranged at regular intervals P1. Figure 1CIn this design, the external coupling element 19 is embodied as a sawtooth-shaped square pyramid. The second main light guide surface 21 faces the first main optical plate surface 23 of the optical plate 9, and is spaced apart by a distance S. The light from the LED light 12 is guided inside the light guide plate 7 via total internal reflection until it encounters the external coupling element 19, through which it is redirected as redirected light 14 to the optical plate 9. The optical plate 9 includes a grid of optical elements 25 arranged at regular intervals P2 on the surface 27 of the second main optical plate. These optical elements 25 shape the redirected light 14 and emit it to the outside as shaped light 16. The grids of the external coupling element 19 and the optical elements 25 are rotated about an angle of 45° relative to each other about an axis A perpendicular to the light guide plate 7 and the optical plate 9. By changing the shape of the external coupling element 19 and the optical elements 25, the intervals P1 and P2, the relative arrangement of the grids of the light guide element 19 and the optical elements 25, and changing the distance S, differences in the characteristics of the shaped light emitted from the lamp 1 to the outside can be obtained. As further shown, the light guide plate has a thickness Dl, and the LED has a light-emitting surface with a height Hl in a direction perpendicular to the first main surface of the light guide plate, where Hl / Dl≈0.6. Furthermore, the external coupling element has a depth Doe, where Doe / Dl≈0.15.

[0058] Figure 1D A partial cross-section of a second embodiment of a lamp 1 according to the present invention is shown, the lamp 1 being similar to Figure 1C The lamp is shown. However, in this second embodiment, a reflector 29 is provided in the space 31 between the back side 4 of the housing 3 and the first main light guide surface 15 to reduce light loss by recirculating light unintentionally emitted from the light guide plate 7 to the back side 4 of the housing 3. In addition, a diffuser 33 is disposed between the light guide plate 7 and the optical plate 9, thereby causing the lamp 1 to emit light to the outside in a more uniform manner.

[0059] Figures 2A-2D Various arrangements of optical structures and / or external coupling structures are shown. The arrangement of elements in the structures is discussed in the context of external coupling structures, but the same applies to optical structures. Figure 2A In this design, the external coupling element 19 is embodied as a square pyramid and arranged in a square grid with regular spacings P1 and P1a in the x and y directions, respectively. The x and y directions define the first primary optical guide surface 15, where P1 = P1a. Figure 2B In the middle, the external coupling element 19 is a square pyramid with decreasing spacing P1''', P1'', P1' as the distance from the edge 8 of the light guide plate 7 increases in the x-direction, and a constant spacing P1a in the y-direction. Figure 2CIn this design, the external coupling element 19 is embodied as a regular hexagonal truncated pyramid with a constant spacing P1 in the x-direction and a constant spacing P1a in the y-direction, different from the spacing P1. The external coupling elements 19 are arranged in a regular hexagonal arrangement, and the lines connecting the six truncated vertices 30 of the six hexagonal external coupling elements around the central hexagonal external coupling element 19a form an equilateral hexagon 26. Figure 2D In this design, the external coupling element 19 is embodied as a regular triangular truncated pyramid with a constant spacing P1 in the x-direction and a constant spacing P1a in the y-direction different from P1. The external coupling elements 19 are arranged in a hexagonal arrangement, and the lines connecting the six truncated vertices 30 of the six adjacent triangular external coupling elements 19 that point to each other form a stretched hexagon 26 in the y-direction.

[0060] Figures 3A-3E Various moiré effects are shown through various combinations of an external coupling structure of a light guide plate and an optical plate with optical elements spaced 2 mm apart, wherein:

[0061] Figure 3A The diagram illustrates a regular, zigzag hexagonal grid arrangement of external coupling elements on an optical guide, combined with a regular, protruding hexagonal and triangular hexagonal grid arrangement on an optical plate. This arrangement features aligned grids, meaning there is no mutual rotation of the grids; the mutual rotation angle α is 0°. The moiré effect obtained through this configuration is considered too strong. In the combined hexagonal and triangular grid, the hexagons contact each other not through their edges but through their points, thus forming a triangular space shaped like a triangular pyramid. This optical arrangement is known on a foil material with the trademark name BWFDiamond.

[0062] Figure 3B The diagram shows a regular, zigzag hexagonal grid arrangement of external coupling elements on a light guide, combined with a regular, protruding hexagonal and triangular hexagonal grid arrangement on an optical plate, featuring a mutually rotating grid arrangement, i.e., the mutual rotation angle α of the grids is essentially 30°. The moiré effect obtained through this configuration is considered very attractive.

[0063] Figure 3C The diagram shows a hexagonal arrangement of protruding hexagonal pyramids in the grid of external coupling elements on a light guide plate, combined with a square arrangement of protruding square pyramids on an optical plate, wherein the grids are aligned such that some sides of the hexagonal pyramids extend parallel to some sides of the square pyramids. The observed moiré effect obtained through this configuration is considered plausible.

[0064] Figure 3DThe diagram shows a hexagonal arrangement of protruding hexagonal pyramids of a grid of external coupling elements on an optical guide plate, combined with a square arrangement of protruding square pyramids on an optical plate, wherein the grids are rotated relative to each other by an angle α, and the sides of the hexagonal pyramids do not extend parallel to the sides of the square pyramids. The observed moiré effect obtained through this configuration is considered acceptable.

[0065] Figure 3E The diagram shows a partial overlap between a regular, zigzag square grid arrangement of external coupling elements on the light guide and a regular, protruding square grid arrangement of square pyramids on the optical plate, with mutually rotating grid arrangements, i.e., where the mutual rotation angle α of the grids is essentially 45°. The moiré effect obtained by this configuration is considered very attractive. A portion of the light guide plate 7 that does not overlap with the optical plate 9 clearly shows the square grid arrangement of the square pyramidal external coupling elements 19 on the light guide plate 7.

[0066] Figure 4A Details of an example of an external coupling element 19 disposed on the surface of a first main light guide (not shown) are shown. The external coupling element 19 is a cone with smooth annular sides 34. The cone has a height of approximately 1.0 mm and a apex angle of 2*35° (slightly rounded). The bottom 32 and top 30 of the cone are both circular, with diameters of approximately 2.0 mm and 0.7 mm, respectively. Figure 4B Details of an example of optical element 25 are shown. Optical element 25 is a square pyramid with four identically shaped sides 36. The truncated pyramid has a height of approximately 0.4 mm and a square base 38 of approximately 1.4 x 1.4 mm and a truncated top 40, wherein the truncated portion is slightly rounded, i.e., the truncated portion here has a 2 x 50° apex angle and is rounded, where the radius R of this circle is approximately 0.5 mm. This allows the light guide plate with this external coupling structure to be easily and inexpensively manufactured via extrusion, costing approximately 25% of Jungbecker's known MLO plate, which requires thermoforming.

[0067] Figures 5A-5B A perspective view of an optical guide plate with an externally coupled element 19 having a size gradient is shown. Figure 5AA complete optical light guide plate 7 is shown, which is provided with a square grid of serrated square pyramids as external coupling elements 19, which increase in depth and size in a direction from the edge 8 of the light guide plate 7—where LEDs (not shown) are positioned toward the centerline 10 of the light guide plate. The square grid has constant spacing P1 and P1a in both the x and y directions, which define a first primary light guide surface 15, where P1 = P1a. Alternatively or additionally, the external coupling elements may be shaped as protruding elements, and / or cones, triangles, hexagons, octagons, or rectangular pyramids, and / or planar elements (such as printed dots or frosted dots).

[0068] Figures 6A-6D Polar coordinate intensity maps (or beam profiles) measured in the x-direction (i.e., 0–180°) and y-direction (i.e., 90–270°) are shown, obtained for several different hexagonal arrangements of the external coupling elements combined with a constant hexagonal arrangement of the optical elements. Specifically, the sawtooth external coupling structure of the light guide (first stage) is varied. Figures 6A-6D In all the figures, the optical elements are prominent grids of hexagons and triangles, with the hexagons contacting each other not by their edges but by their points, thus forming a triangular space shaped like a triangular pyramid. This optical arrangement is known on a foil material trademarked as BWF Diamond (and further known as BWF Diamond). Table 1 below shows the characteristics of the obtained beam profile as a function of variations in some parameters of the external coupling element structure.

[0069] picture Optical structure External coupling element Top corner mutual rotation α LOR UGR L65 6A BWF Diam cone 2*35° 30° 82% 18.0 2500 6B BWF Diam hexagonal pyramid 2*35° 30° 84% 17.8 2250 6C BWF Diam cone 2*50° 30° 83% 18.8 2650 6D BWF Diam Square pyramid 2*50° 30° 87% 17.8 2411

[0070] Table 1: Comparable examples of the hexagonal arrangement of the BWF Diamond's prominent optical elements combined with various shapes of sawtooth external coupling elements arranged hexagonally on the first main surface of the light guide plate.

[0071] exist Figure 6A In this context, a given combination results in the luminaire providing a beam of light that is highly symmetrical in both the x and y directions. Figure 6B In this context, a given combination results in the luminaire providing a beam that is not entirely asymmetrical in the x and y directions, but has a high light output ratio (LOR), which is the ratio between output power and input power. Figure 6C In this context, the given combination results in the luminaire providing a batwing-shaped beam profile in the x-direction. Figure 6D In this context, the given combination results in the luminaire providing a symmetrical beam in both the x and y directions, which is combined with a high LOR and a desired low UGR.

[0072] Figure 7The optimal position of the external coupling element 19 closest to the edge wall 8 of the light guide plate 7 is shown.

[0073]

[0074] D = the distance between the first main light guide surface 15 and the LED 11 in the direction perpendicular to the first main light guide surface 15;

[0075] Dl = the thickness of the light guide plate 7 in the direction perpendicular to the first main light guide surface 15; and

[0076] n = the refractive index of the material of the light guide plate 7.

[0077] By avoiding the presence of external coupling elements in the area defined by L1 to L2, bright spots that would be detrimental to meeting UGR and L65 office compliance requirements are avoided. L1 and L2 indicate the distance from edge wall 8 (i.e., the incident surface of light guide 7) to the external coupling element 19 closest to edge wall 8, shown as the colored laser point in the figure. If the external coupling element 19 is located closer to edge wall 8 than L1, light from the LED light source located on edge wall 8 (incident surface) cannot reach the external coupling element 19 due to refraction occurring at the critical angle θc. When the external coupling element 19 is located further away from edge wall 8 than L2, a virtual image of the LED light source can no longer be formed, thus avoiding bright spots. However, if the first reachable external coupling element 19 extends too far beyond L2 (and therefore too far from edge wall 8), a dark gap occurs. Therefore, the optimal position of the first reachable external coupling element 19 is at position L2, i.e., external coupling element 19b. Accordingly, this feature can be considered an independent invention in itself.

[0078] Figure 8 A lighting system 100 is shown, comprising a plurality of luminaires 1 according to the invention, which are aligned in a grid and together form a suspended false ceiling 200. The luminaires 1 can be individually controlled to achieve dynamic lighting effects.

Claims

1. A lighting fixture, comprising: A stack of parallel light-transmitting plates, including light guide plates and optical plates. The light guide plate includes a first main light guide surface and a second main light guide surface connected by edge walls. LEDs are arranged along the edge walls and provide edge illumination during operation. At least one of the main light guide surfaces is provided with an external coupling structure, which includes external coupling elements arranged at a substantially constant first spacing P1 in the x-direction and at a substantially constant first spacing P1a in the y-direction perpendicular to the x-direction. The optical plate includes a first main optical surface and a second main optical surface, the first main optical surface facing the second main light guide surface, and only one of the first main optical surface and the second main optical surface is provided with an optical structure including optical elements arranged at a substantially constant second spacing P2. The second main optical guide surface and the first main optical surface are spaced apart by a distance S in a direction perpendicular to the main optical guide surface, wherein S is in the range of 0-25 mm. P1, P1a, and P2 are in the range of 1-7 mm, and the ratios P1 / P2 and P1a / P2 are in the range of 0.5-2.

2. The lighting fixture according to claim 1, wherein, P1, P1a, and P2 are further within the range of 1.5–6 mm.

3. The lighting fixture according to claim 2, wherein, The ratios P1 / P2 and P1a / P2 are further within the range of 0.8-1.

25.

4. The lighting fixture according to claim 1, wherein, The ratios P1 / P2 and P1a / P2 are further within the range of 0.8-1.

25.

5. The luminaire according to any one of claims 1-4, wherein, S further falls within the range of 5-9 mm.

6. The lighting fixture according to claim 1, wherein, The external coupling element and the optical element are arranged in at least one of an octagonal, hexagonal, square, rectangular and triangular arrangement.

7. The luminaire according to claim 6, wherein, The external coupling element and the optical element have relative rotational positions about an axis A perpendicular to the second main light guide surface. For a hexagonal arrangement of the external coupling element and the optical element, they rotate relative to each other at an angle α of approximately 30 degrees; for a square / rectangular arrangement of the external coupling element and the optical element, they rotate relative to each other at an angle α of approximately 45 degrees; and for a triangular arrangement of the external coupling element and the optical element, they rotate relative to each other at an angle α of approximately 90 degrees.

8. The lighting fixture according to claim 1, wherein, The external coupling structure is disposed only on the first main optical guide surface, and the optical structure is disposed only on the second main optical surface.

9. The luminaire according to claim 8, wherein, The external coupling element is serrated, and the optical element is protruding.

10. The lighting fixture according to claim 1, wherein, The external coupling element and the optical element have a conical shape.

11. The luminaire according to claim 1, wherein, The external coupling element and the optical element have a circular cone or a 4-faceted or 6-faceted cone.

12. The luminaire according to claim 10, wherein, The cone of the optical element has an apex angle in the range of 100-120 degrees, and the cone of the external coupling element has an apex angle in the range of 60-140 degrees.

13. The luminaire according to claim 10, wherein, The cone of the optical element has an apex angle in the range of 105-100 degrees, and the cone of the external coupling element has an apex angle in the range of 60-140 degrees.

14. The luminaire according to claim 10, wherein, The cone of the optical element has an apex angle in the range of 100-120 degrees, and the cone of the external coupling element has an apex angle in the range of 70-90 degrees.

15. The luminaire according to claim 10, wherein, The cone of the optical element has an apex angle in the range of 105-100 degrees, and the cone of the external coupling element has an apex angle in the range of 70-90 degrees.

16. The luminaire according to claim 1, wherein, The light guide plate has a rectangular shape with two opposing short edge walls and two opposing long edge walls, and the LED is arranged at at least one long edge wall.

17. The luminaire according to claim 16, wherein, The LEDs are arranged at two long edge walls, and the external coupling structure has a protruding size and / or a serrated depth, which gradually increases in a direction transverse to the long edge walls over substantially the entire distance from the long edge walls to the long center line of the light guide plate parallel to the long edges.

18. The luminaire according to claim 1, wherein, A diffuser is provided between the light guide plate and the optical plate, wherein the diffuser is in the range of 10-30%.

19. The luminaire according to claim 1, wherein, The luminaire includes a reflector that faces the first main light guide surface and extends parallel to the first main light guide surface.

20. The luminaire according to claim 1, wherein, The parallel light-transmitting plate is an extruded plate made of a transparent material, which is selected from polymethyl methacrylate, polycarbonate, and polyethylene.

21. The lamp according to claim 1, wherein, In a direction perpendicular to the first main light guide surface of the light guide plate, the light guide plate has a thickness Dl, and the LED has a light-emitting surface with a height Hl, where 0.3≤Hl / Dl≤0.

7.

22. The luminaire according to claim 1, wherein, There are no external coupling elements in the region between L1 and L2 on the first main light guide surface along the edge wall of the light guide plate, and the LEDs are arranged along the region, where L1 and L2 are distances from the incident surface of the light guide, and wherein: Where D = the distance between the first main light guide surface and the LED in a direction perpendicular to the first main light guide surface; Dl = the thickness of the light guide plate in the direction perpendicular to the first main light guide surface; and n = the refractive index of the material of the light guide plate.

23. A lighting system comprising at least two luminaires as described in any one of claims 1-22, wherein the luminaires are aligned with each other and / or form an enclosed inlaid wall / ceiling.

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