Lighting equipment used to provide a shimmering appearance

Abstract

The present invention relates to a lighting device having a relatively simple structure, which is arranged to provide a flashing light effect. The lighting device comprises: (i) a lens array (110) having a plurality of lenses (110a-d) and a focal surface (111) located at a focal length from the lens array (110), and (ii) a light source array (120) having a plurality of light sources (120a-d), each light source (120a-d) being arranged to emit light towards the lens array (110), wherein the light output is distributed around a main axis (121a-d), and the light sources (120a-d) together define a light emitting surface (122) of the light source array (120). The light emitting surface (122) of the light source array (120) substantially coincides with the focal surface (111) of the lens array (110). In a projection plane (130) perpendicular to the main axis (121a-d), each light source (120a-d) forms a combination (132a-p) with a nearest lens, each combination (132a-p) having a displacement distance (131), the displacement distance (131) having a displacement length (L) and a displacement direction (d), so that the lighting device (100) has a plurality of displacement lengths (L) and a plurality of displacement directions (d). The plurality of displacement lengths (L) include at least two different displacement lengths (L), and the plurality of displacement directions (d) include at least two different displacement directions (d).

Description

Technical Field

[0001] The present invention relates to a lighting device for providing a glittering appearance. Background Art

[0002] Many different types of lamps are available in the market today. Examples of such lamps are panel lamps for use in or on a ceiling or wall. Other examples are hanging lamps. Lamps are typically designed to have a spatially uniform brightness appearance. In other words, when looking at a lamp, one typically sees an area of ​​uniform brightness.

[0003] Generally speaking, it is difficult for lamp manufacturers to stand out from the competition. To this end, lamps with a more interesting or dramatic appearance are needed.

[0004] The aforementioned needs can be met, for example, by customizable lighting systems consisting of light-emitting architectural panels. Although such lighting systems are very versatile and high-end, a need still remains for a simpler way to generate interesting (dynamic) light effects in a luminaire.

[0005] US-2019 / 120460 discloses a lamp comprising a plurality of light sources arranged in a planar array, each light source having a light emitting diode (LED) and an optical element. The optical element comprises a substantially transparent first portion having a first refractive index, the first portion being configured to receive light from the LED. The optical element further comprises a substantially transparent second portion having a second refractive index greater than the first refractive index, the second portion having an emitting surface having a two-petal shape. Summary of the invention

[0006] It is an object of the present invention to provide a lighting device which is able to produce interesting (dynamic) light effects while the lighting device itself has a relatively simple structure.

[0007] According to one aspect of the present invention, the object is achieved by means of a lighting device, which includes (i) a lens array having a plurality of lenses and a focal surface located at a focal length from the lens array, (ii) a light engine having one or more light-emitting elements and a light exit window, and (iii) a covering layer covering the light exit window. The covering layer has a surface portion defining a plurality of light exit areas, each light exit area having a higher transmittance than the surface portion. The light exit areas constitute a light source array having a plurality of light sources, each light source being arranged to emit light toward the lens array, wherein the light output is distributed around a main axis, and the light sources together define a light emitting surface of the light source array. The light emitting surface of the light source array substantially coincides with the focal surface of the lens array. In a projection plane perpendicular to the main axis, each light source forms a combination with the nearest lens. Each such combination of a light source and its associated nearest lens has a displacement distance, which has a displacement length and a displacement direction. Therefore, the lighting device has a plurality of displacement lengths and a plurality of displacement directions.

[0008] The plurality of displacement lengths consists of n displacement lengths, and the plurality of displacement directions consists of n displacement directions, where n is equal to 2 or greater.

[0009] n displacement lengths are distributed in m 1 On a subset of displacement lengths, m 1 Each of the subsets consists of one or more identical displacement lengths. The n displacement directions are distributed in m 2 On a subset of displacement directions, m 2 Each of the subsets consists of one or more identical displacement directions. 1 and m 2 Each of is equal to 2 or greater.

[0010] In other words, the plurality of displacement lengths includes at least two different displacement lengths, and the plurality of displacement directions includes at least two different displacement directions.

[0011] Quantitym 1 and / or quantity m 2 It may be at least 10% of the number n, such as at least 20%, at least 50%, at least 75% or at least 90%. For example, if the light source array of the lighting device has 1000 light sources, the plurality of displacement lengths consists of 1000 displacement lengths and the plurality of displacement directions consists of 1000 displacement directions (n=1000). The 1000 displacement lengths may be distributed in at least 100 identical displacement lengths (m 1 ≥100), such as at least 200, at least 500, at least 750 or at least 900 subsets. Simultaneously or alternatively, the 1000 displacement directions may be distributed over subsets of at least 100 identical displacement directions (m 2≥100), such as at least 200, at least 500, at least 750, or at least 900 subsets.

[0012] The above described lighting device has a relatively simple structure and is arranged to provide a flashing light effect to an observer.

[0013] The plurality of displacement lengths may be distributed within a displacement length range having an upper displacement length limit, wherein a ratio of the upper displacement length limit to the focal length is at least 0.18.

[0014] In the above lighting device, the light exit area may be a through opening, and the surface portion of the cover layer may be reflective or light transmissive, such as diffusely light transmissive and / or colored.

[0015] The light engine may have a light mixing cavity having an inner surface arrangement having a back surface opposite to the light exit window and a side surface separating the back surface from the light exit window, wherein one or more light emitting elements are arranged on at least one of the back surface and the side surface, and wherein the one or more light emitting elements are arranged to emit light toward the light exit window directly or via reflection on the inner surface arrangement.

[0016] The light engine may have a light guide element having a light incoupling surface and a light outcoupling surface, wherein the one or more light emitting elements are arranged to emit light into the light guide element via the light incoupling surface, wherein the light guide element comprises light extraction features to redirect light out of the light guide element via the light outcoupling surface, and wherein the light outcoupling surface of the light guide element constitutes a light exit window of the light engine.

[0017] The focal surface of the lens array and the light emitting surface of the light source array may be flat surfaces oriented parallel to each other.

[0018] Each of the plurality of lenses and the plurality of light sources may be arranged on a regular grid or on an irregular grid.

[0019] The term "grid" should be interpreted as referring to a pattern of positions. This grid or pattern of positions can be regular or irregular. In a regular grid, the positions that make up the pattern repeat in a predictable manner. In an irregular grid, the positions that make up the pattern repeat in an unpredictable manner. An irregular grid is a pattern of positions that is not defined by any symmetry, shape, formal arrangement, or continuity.

[0020] The plurality of lenses may be distributed on a regular lens grid with a shortest lens spacing. Each displacement length may be equal to or less than half of the shortest lens spacing. The regular lens grid may be one of a rectangular grid, a square grid, or a hexagonal grid. The plurality of light sources may also be distributed on a regular light source grid, wherein the regular lens grid and the regular light source grid are rotated relative to each other.

[0021] The plurality of lenses may be distributed on an irregular lens grid, while the plurality of light sources are distributed on a regular light source grid.

[0022] The plurality of lenses may be distributed on an irregular lens grid, and the plurality of light sources may be distributed on an irregular light source grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] A lighting device according to the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which corresponding reference numerals indicate corresponding parts, and in which:

[0024] Figure 1 shows a cross-sectional view of a lighting device;

[0025] Figure 2 When viewed from the lens array toward the light source array Figure 1 lighting equipment;

[0026] Figure 3 When viewed from the lens array toward the light source array Figure 1 lighting equipment;

[0027] Figure 4 When viewed from the lens array toward the light source array Figure 1 lighting equipment;

[0028] Figure 5 Shows Figure 1 an enlarged portion of a cross-sectional view of which focuses on a combination of a light source and its associated nearest lens;

[0029] Figure 6 shows a cross-sectional view of a lighting device;

[0030] Figure 7 shows a cross-sectional view of a lighting device;

[0031] Figure 8 shows a cross-sectional view of a lighting device;

[0032] Fig. 9 shows the lighting device when viewed from the direction of the lens array towards the light source array;

[0033] Fig.10 shows the lighting device when viewed from the direction of the lens array towards the light source array; and

[0034] Fig.11 Three different light distributions are shown as seen by an observer moving from left to right in front of the lighting device.

[0035] The schematic drawings are not necessarily to scale. DETAILED DESCRIPTION

[0036] Figure 1 A cross-sectional view of a lighting device 100 is shown. The lighting device 100 has a lens array 110 having a plurality of lenses 110a-d. The lens array 110 is a microlens array, wherein the lenses 110a-d are spherical lenses. The lens array 110 also has a focal surface 111, which is a surface containing the focal points of the lenses 110a-d.

[0037] The lighting device 100 also has a light source array 120 having a plurality of light sources 120a-d. Each light source 120a-d is arranged to emit light towards the lens array 110, wherein the light output is distributed around a main axis 121a-d.

[0038] The light sources 120a-d together define a light emitting surface 122 of the light source array 120. The light emitting surface 122 of the light source array 120 substantially coincides with the focal surface 111 of the lens array 110.

[0039] In the lighting device 100, the focal surface 111 of the lens array 110 and the light emitting surface 122 of the light source array 120 are flat surfaces oriented parallel to each other. The main axes 121a-d are oriented parallel to each other and are perpendicular to each of the focal surface 111 of the lens array 110 and the light emitting surface 122 of the light source array 120.

[0040] Alternatively, the focal surface of the lens array and the light emitting surface of the light source array can be curved surfaces or any other type of surface, as long as the light emitting surface of the light source array substantially coincides with the focal surface of the lens array. For example, the lens array can be shaped in the form of a spherical dome or an ellipsoidal dome.

[0041] Figure 2 Again, it shows Figure 1 , but now when viewed in a direction from the lens array 110 towards the light source array 120.

[0042] Figure 2 A projection plane 130 is shown. The projection plane 130 is oriented perpendicular to the major axes 121a-d. The projections of the lenses (larger circles) and light sources (smaller circles) are shown in the projection plane 130. The centers of the projections of the lenses and light sources are shown as black dots.

[0043] If you can Figure 2 As can be seen in FIG. 1 , the lighting device 100 has sixteen lenses distributed on a square lens grid with a lens pitch p. The lighting device 100 also has sixteen light sources distributed in an irregular light source grid.

[0044] Alternatively, the lighting device can have any number of lenses and any number of light sources, where the number of lenses can be equal to or different from the number of light sources. In addition, each of the plurality of light sources and the plurality of lenses can be arranged on a regular or irregular grid. Examples of suitable regular grids are rectangular grids (such as square grids) and hexagonal grids. Examples of suitable irregular grids are randomized grids.

[0045] In projection plane 130, each light source is combined with the closest lens. In order to find the combination of a light source and its associated closest lens, one must look at the projection centers of the light source and the lens in projection plane 130. Each projection center of the light source is separated from the projection center of the lens by a certain distance (which can be zero). The lens whose projection center is separated from the projection center of the light source in projection plane 130 by the shortest distance is the closest lens relative to the light source. For example, light source 120a is combined with closest lens 110a, light source 120b is combined with closest lens 110b, light source 120c is combined with closest lens 110c, and light source 120d is combined with closest lens 110d.

[0046] Figure 3 Again, it shows Figure 2 For the sake of clarity, the projection of the light source and the lens has been omitted, and only the projection centers of the light source and the lens are shown. In the projection plane 130, each combination of the light source and its associated nearest lens has a displacement distance 131, which is the distance between the projection centers of the light source and its associated nearest lens.

[0047] Each displacement distance 131 is characterized by a displacement length L and a displacement direction d. The displacement direction d represents the orientation of the displacement distance 131 in the projection plane 130. Figure 3 Indicated by a dotted straight line.

[0048] All displacement distances 131 together represent a plurality of displacement lengths L and a plurality of displacement directions d.

[0049] In the lighting device 100, each displacement length L is equal to or less than half of the lens pitch p, but this need not necessarily be the case. When the lens array has different pitches in two mutually orthogonal directions, each displacement length L may be equal to or less than half of the shortest lens pitch, but again, this need not necessarily be the case.

[0050] Figure 4 Again, it shows Figure 2 and Figure 3The projection plane 130. For the sake of clarity, the dotted line representing the displacement direction d has been omitted, and only the projection center of the light source and the lens and the displacement distance are still shown. Figure 4 Combinations 132a-p of light sources and associated proximal lenses are shown, each combination 132a-p having a displacement distance characterized by a displacement length L and a displacement direction d.

[0051] Figures 1 to 4 The lighting device 100 shown in has sixteen combinations of light sources and associated closest lenses, each combination having a displacement length L. In alternative lighting devices, there may be more or less than sixteen combinations of light sources and associated closest lenses, such as at least 50 combinations, or at least 100 combinations, or at least 500 combinations, or at least 1000 combinations.

[0052] Two or more combinations of light sources and associated nearest lenses may have the same displacement length L and the same displacement direction d, as long as there are at least two different displacement lengths L and at least two different displacement directions d within all combinations of light sources and associated nearest lenses.

[0053] exist Figure 4 In the embodiment, the combinations 132b, 132k and 132n have the same displacement length L and the same displacement direction d. The same applies to the combinations 132d and 132j ​​and the combinations 1321 and 132o, respectively.

[0054] Combinations 132a and 132g have the same displacement length L but opposite displacement directions d. The same applies to combinations 132h and 132m and combinations 132i and 132o, respectively.

[0055] The combinations 132f and 132p have the same displacement length L but mutually perpendicular displacement directions d.

[0056] The combinations 132c and 132f have the same displacement direction d but different displacement lengths L. The same applies to the combinations 132e, 132g, 1321 and 132o.

[0057] All combinations 132a-p together represent a plurality of displacement lengths L and a plurality of displacement directions d. The plurality of displacement lengths L includes several different displacement lengths L, and the plurality of displacement directions d includes several different displacement directions d.

[0058] The displacement length L is distributed in the displacement length range. The displacement length range has a displacement length lower limit L min and the upper limit of displacement length L max .

[0059] exist Figures 1 to 4 In the lighting device 100 shown in FIG. 1 , the lower limit of the displacement length Lmin In the alternative lighting device, the lower limit of the displacement length L min Can be zero.

[0060] In operation, Figures 1 to 4 The lighting device 100 provides a light output that is perceived by an observer as a shimmering light effect.

[0061] Figure 5 Shows Figure 1 1 is an enlarged portion of a cross-sectional view of FIG. 1 , which focuses on the combination of light source 120a and its associated nearest lens 110a. Figure 5 1 and 2 are also shown the displacement length L of the combination of the projection plane 130 and the light source 120a and the lens 110a. The displacement length L has a non-zero value because the centers of the light source 120a and the lens 110a are offset relative to each other by an offset angle α. The offset angle α is the angle between the principal axis 121a and the line connecting the center of the light source 120a and the center of the nearest lens 110a. The tangent of the offset angle α is equal to the ratio of the displacement length L and the focal length F.

[0062] For each combination of a light source and its associated nearest lens, the imaginary line segment connecting the center of the light source and the center of the lens lies on the surface of an imaginary cone whose cone aperture is equal to twice the offset angle α, whose cone height is equal to the focal length F, and whose cone base radius is equal to the displacement length L.

[0063] The inventors have found that in order to optimize the light effect of the flash, the cone aperture should be at least 20 degrees, such as at least 40 degrees, or at least 90 degrees. For a cone aperture of 20 degrees, the ratio between the cone base radius and the cone height is about 0.18, which corresponds to the ratio between the displacement length L and the focal length F. For a cone aperture of 40 degrees, the ratio between the cone base radius and the cone height is about 0.36, which corresponds to the ratio between the displacement length L and the focal length F. For a cone aperture of 90 degrees, the ratio between the cone base radius and the cone height is equal to 1, which corresponds to the ratio between the displacement length L and the focal length F.

[0064] Figure 6 A cross-sectional view of a lighting device 400 is shown. The lighting device 400 has a lens array 410 having a plurality of lenses 410a-d. The lens array 410 also has a focal surface 411, which is a surface containing the focal points of the lenses 410a-d.

[0065] The lighting device 400 also has a light engine 430. The light engine 430 has a light mixing cavity 431, which has an inner surface arrangement. The inner surface arrangement has a back surface 433 opposite to the light exit window 432 and a side surface 434 separating the back surface 433 and the light exit window 432. A plurality of light emitting elements 435a-f are arranged on the back surface 433. The light emitting elements 435a-f are light emitting diodes. Alternatively, the light emitting elements may be other types of light emitting elements, such as laser diodes.

[0066] The light emitting elements 435 a - e are arranged to emit light directly towards the light exit window 432 .

[0067] In the lighting device 400, a cover layer 440 covers a light exit window 432 of a light engine 430. The cover layer 440 has a surface portion 441 that defines a plurality of light exit areas 442a-d. The surface portion 441 is reflective, and each of the light exit areas 442a-d is a through opening in the cover layer 440. Because the surface portion 441 is reflective, light emitted through the light exit window 432 of the light engine 430 but not incident on the light exit areas 442a-d of the cover layer 440 is reflected by the surface portion 441 back into the mixing chamber 431 of the light engine 430, thereby improving the overall efficiency and providing a flashing light effect that enhances contrast.

[0068] Alternatively, the surface portion can be light-transmissive, and the light exit area does not have to be a through opening, as long as the light exit area has a higher transmittance than the surface portion. The light exit area can be a transparent area defined by a diffuse light-transmissive and / or colored surface portion, not necessarily a through opening. For example, the cover layer can be a foil with through holes in a blue diffuse light-transmissive surface portion, so that the lighting device is arranged to provide a flashing light effect on a blue diffuse background lighting. The cover layer can also include imaging (imagery) - such as a blue sky with clouds, or cherry trees, or a night sky scene - so that the flashing light effect adds a dynamic effect to a static background image.

[0069] In the lighting device 400, the light exit areas 442a-d of the cover layer 440 constitute a light source array 420 having a plurality of light sources 420a-d. The light sources 420a-d are arranged to emit light toward the lens array 410, wherein the light output is distributed around the main axes 421a-d. The light sources 420a-d together define a light emitting surface 422 of the light source array 420.

[0070] Figure 7 An alternative layout of the lighting device 400 is shown, wherein a plurality of light emitting elements 435a-f are arranged on a side surface 434 of the light mixing cavity 431. The light emitting elements 435a-e are now arranged to emit light towards the light exit window 432 indirectly, i.e. via reflection on an inner surface arrangement of the light mixing cavity 431.

[0071] Figure 8 A cross-sectional view of a lighting device 500 is shown. The lighting device 500 has a lens array 510 having a plurality of lenses 510a-d. The lens array 510 also has a focal surface 511, which is a surface containing the focal points of the lenses 510a-d.

[0072] The lighting device 500 further has a light engine 530. The light engine 530 has a light guide element 531 having a first light incoupling surface 533a and a second light incoupling surface 533b positioned opposite the first light incoupling surface 533a. The light guide element 531 further has a light outcoupling surface 532. A light emitting element 535a is arranged to emit light into the light guide element 531 via the first light incoupling surface 533a, and a light emitting element 535b is arranged to emit light into the light guide element 531 via the second light incoupling surface 533b. The light emitting elements 535a and 535b are light emitting diodes, but they may alternatively be other types of light emitting elements, such as laser diodes.

[0073] The light guide element 531 has light extraction features 534a-f on a surface opposite to the light outcoupling surface 532. The light extraction features 534a-f are used to redirect light out of the light guide element 531 via the light outcoupling surface 532. The light outcoupling surface 532 of the light guide element 531 constitutes a light exit window of the light engine 530.

[0074] In the lighting device 500, the cover layer 540 covers the light exit window 532 of the light engine 530. The cover layer 540 is similar to Figure 6 and Figure 7 The cover layer 440 is shown in FIG.

[0075] The cover layer 540 has a surface portion 541 defining a plurality of light exit areas 542a-d. The surface portion 541 is reflective, and each light exit area 542a-d is a through opening in the cover layer 540. The light exit areas 542a-d of the cover layer 540 constitute a light source array 520 having a plurality of light sources 520a-d. The light sources 520a-d are arranged to emit light toward the lens array 510, wherein the light output is distributed around the main axis 521a-d. The light sources 520a-d together define a light emitting surface 522 of the light source array 520.

[0076] Similar to Figure 2 , Fig. 9 The lighting device is shown when viewed from the direction of the lens array towards the light source array.

[0077] Fig. 9A projection plane 130 is shown. The projections of the lens (larger circle) and the light source (smaller circle) are shown in the projection plane 130. The centers of the projections of the lens and the light source are shown as black dots.

[0078] Fig. 9 The lighting device shown in FIG. 1 has a lens spacing p. 1 The lighting device also has sixteen lenses distributed at a light source spacing of p 2 Sixteen light sources in a square light grid. Lens spacing p 1 Equal to the light source spacing p 2 Alternatively, the lens pitch p 1 Can be different from the light source spacing p 2 The square lens grid and the square light source grid are rotated relative to each other.

[0079] Fig.10 Shows Fig. 9 1 , wherein for the sake of clarity, the projection of the light source and the lens has been omitted, and only the projection centers of the light source and the lens are still shown. In the projection plane 130, each combination of the light source and its associated nearest lens has a displacement distance 131, which is the distance between the projection centers of the light source and its associated nearest lens.

[0080] Each displacement distance 131 is characterized by a displacement length L and a displacement direction d. The displacement direction d represents the orientation of the displacement distance 131 in the projection plane 130. Fig.10 Indicated by a dotted straight line.

[0081] All displacement distances 131 together represent a plurality of displacement lengths L and a plurality of displacement directions d. In all combinations of light sources and associated closest lenses, there are at least two different displacement lengths L and at least two different displacement directions d.

[0082] Fig.11 Three different light distributions are shown as seen by an observer moving from left to right in front of the lighting device according to the invention.

[0083] Each light source of the light source array has a nearest lens of the lens array. The lens array has 800 lenses arranged on a square grid with a lens pitch of 3.0 mm (± 0.5 mm) in a matrix of 25 rows and 32 columns. The lens array also has a focal length F of 12 mm.

[0084] Each combination of a light source and its associated nearest lens is arranged to produce a light output component of the lighting device. Light emitted by a light source may also be incident on and pass through a lens that is not the nearest lens of the light source, such as an adjacent or next adjacent lens. This so-called crosstalk will also give a light output component.

[0085] All light output components together constitute the light output of the lighting device. Depending on the viewing position of the observer, only a portion of the light output of the lighting device will be visible as a lighting pattern.

[0086] for Fig.11 For each viewing position shown in , the visible illumination pattern is indicated by white squares surrounded by black squares, which represent the output components of visible and invisible light in that viewing position, respectively.

[0087] When an observer moves from left to right in front of the lighting device, a (random) flashing light effect can be observed.

[0088] for Fig.11 At each viewing position shown in , the light output components that together constitute the illumination pattern are distributed in a circular area with a diameter of D. The circular area with a diameter of D represents the area in which the flash occurs, and this area moves with the observer.

[0089] The diameter D of the area where the flash occurs depends on the viewing distance V between the lighting device and the observer, the maximum displacement length L max , and the focal length F of the lens array, according to:

[0090]

[0091] for Fig.11 Lighting equipment, maximum displacement length L max is 0.5 mm, and the focal length F is 12 mm. When the observer is at a distance V of 2 meters from the lighting device, the diameter D of the area where the flash occurs is approximately 17 cm. Alternatively, if the maximum displacement length L max Increasing to 2.0 mm, the diameter D of the area where the flash occurs increases to approximately 67 cm, which will essentially cover the entire area of ​​a 60 cm by 60 cm lighting panel.

[0092] In addition to lighting devices in the form of panels of 60 cm by 60 cm, the invention can also be applied in smaller lighting devices, such as 10 cm by 10 cm or even smaller. The flashing light effect, which is difficult to replicate, can then be used as a copy protection measure or anti-counterfeiting measure.

[0093] In the above lighting device, the lens array and the light source array are stationary and in a fixed relationship relative to each other. Alternatively, the lens array and the light source array may be movable relative to each other to provide a dynamic flashing light effect, even for a stationary observer.

[0094] It should be noted that the above-mentioned lighting devices illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative lighting devices based on the invention without departing from the scope of the appended claims.

[0095] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0096] The mere fact that certain features are cited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage. The various aspects discussed above may be combined in order to provide additional advantages. Furthermore, it will be understood by those skilled in the art that the features of two or more different dependent claims may be combined.

Claims

1. A lighting device (400), comprising: - a lens array (410) having a plurality of lenses (410a-d) and a focal surface (411) located at a focal length from the lens array (410), - a light engine (430) having one or more light emitting elements (435a-f) and a light exit window (432), and - a covering layer (440) covering the light exit window (432), wherein the cover layer (440) has a surface portion (441) defining a plurality of light exit areas (442a-d), each light exit area (442a-d) having a higher transmittance than the surface portion (441), wherein the light exit regions (442a-d) constitute a light source array (420) having a plurality of light sources (420a-d), each light source (420a-d) being arranged to emit light towards the lens array (410), wherein the light output is distributed around a main axis (421a-d), and the light sources (420a-d) together define a light emitting surface (422) of the light source array (420), wherein the light emitting surface (422) of the light source array (420) substantially coincides with the focal surface (411) of the lens array (410), wherein in a projection plane (130) perpendicular to the principal axis (421a-d), each light source (420a-d) forms a combination (132a-p) with a nearest lens, each combination (132a-p) having a displacement distance (131), the displacement distance (131) being the distance between the projection centers of the light source (420a-d) and its associated nearest lens, the displacement distance (131) having a displacement length (L) and a displacement direction (d), so that the lighting device (400) has a plurality of displacement lengths (L) and a plurality of displacement directions (d), and wherein the plurality of displacement lengths (L) comprises at least two different displacement lengths (L), and the plurality of displacement directions (d) comprises at least two different displacement directions (d), and wherein the surface portion (441) of the cover layer (440) is light-transmissive, and wherein the light exit regions (442a-d) are through-openings.

2. The lighting device (400) according to claim 1, wherein the plurality of displacement lengths (L) are distributed in a range having an upper displacement length limit (L max ) within the displacement length range, the upper limit of the displacement length (L max The ratio of the focal length (F) to the focal length (F) is at least 0.

18.

3. The lighting device (400) according to claim 1, wherein a surface portion (441) of the cover layer (440) is diffusely light-transmissive and / or colored.

4. The lighting device (400) according to claim 2, wherein a surface portion (441) of the cover layer (440) is diffusely light-transmissive and / or colored.

5. The lighting device (400) according to claim 1, wherein a surface portion (441) of the cover layer (440) is light reflective, and wherein the light exit areas (442a-d) are through-openings.

6. An illumination device (400) according to any one of claims 1 to 5, wherein the light engine (430) has a light mixing cavity (431), the light mixing cavity (431) having an inner surface arrangement, the inner surface arrangement having a back surface (433) opposite to the light exit window (432) and a side surface (434) separating the back surface (433) and the light exit window (432), wherein the one or more light-emitting elements (435a-f) are arranged on at least one of the back surface (433) and the side surface (434), and wherein the one or more light-emitting elements are arranged to emit light toward the light exit window (432) directly or via reflection on the inner surface arrangement.

7. The lighting device (500) according to any one of claims 1 to 5, wherein the light engine (530) has a light guide element (531), the light guide element (531) having a light incoupling surface (533a-b) and a light outcoupling surface (532), wherein the one or more light emitting elements (535a-b) are arranged to emit light into the light guide element (531) via the light incoupling surface (533a-b), wherein the light guide element (531) comprises light extraction features (534a-f) to redirect light out of the light guide element (531) via the light outcoupling surface (532), and wherein the light outcoupling surface (532) of the light guide element (531) constitutes a light exit window of the light engine (530).

8. The lighting device (400) according to any one of claims 1 to 5, wherein the focal surface (411) of the lens array (410) and the light emitting surface (422) of the light source array (420) are flat surfaces oriented parallel to each other.

9. The lighting device (400) according to any one of claims 1 to 5, wherein the plurality of lenses (410a-d) are distributed on a regular lens grid having a shortest lens spacing (p1), and wherein each displacement length (L) is equal to or less than half of the shortest lens spacing (p1).

10. The lighting device (400) of claim 9, wherein the regular lens grid is one of a rectangular grid, a square grid, or a hexagonal grid.

11. The lighting device (400) according to claim 9, wherein the plurality of light sources (420a-d) are distributed on an irregular light source grid.

12. The lighting device (400) of claim 9, wherein the plurality of light sources (420a-d) are distributed on a regular light source grid, and wherein the regular lens grid and the regular light source grid are rotated relative to each other.

13. The lighting device (400) according to any one of claims 1 to 5, wherein the plurality of lenses (410a-d) are distributed on an irregular lens grid, and wherein the plurality of light sources (420a-d) are distributed on a regular light source grid.

14. The lighting device (400) according to any one of claims 1 to 5, wherein the plurality of lenses (410a-d) are distributed on an irregular lens grid, and wherein the plurality of light sources (420a-d) are distributed on an irregular light source grid.

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