A LED filament arrangement

Abstract

A LED filament arrangement (1) configured to, in operation, emit LED filament arrangement light (2) and comprising a LED filament (31), the LED filament (31) being configured to, in operation, emit LED filament light (41), wherein the LED filament (31) is arranged in a collimator (51), wherein the collimator (i) is reflective and elongated, (ii) comprises a light exit window (61), and (iii) is configured to redirect the LED filament light (41) in a direction towards the light exit window (61), wherein the LED filament arrangement (1) further comprises a plurality of reflecting lamellae (71) arranged in the collimator (51), and wherein the plurality of reflecting lamellae (71) are arranged extending perpendicular to the LED filament (31).

Description

[0001] 2025PF80051

[0002] 1

[0003] A LED FILAMENT ARRANGEMENT

[0004] FIELD OF THE INVENTION

[0005] The invention relates to a LED filament arrangement configured to, in operation, emit LED filament arrangement light and comprising a LED filament, the LED filament being configured to, in operation, emit LED filament light, the LED filament being arranged in a collimator.

[0006] BACKGROUND OF THE INVENTION

[0007] A trend in lighting is LED filament lamps. A LED filament lamp is a lamp which is designed to resemble a traditional incandescent light bulb with a visible filament for aesthetic and light distribution purposes, but with the high efficiency of LEDs. LED filaments being designed for LED retrofit lamps, where LED filament is fixed to supporting metal stem and enclosed in protective glass bulb cover, are widely used. However, standard LED filaments within glass bulbs have to be cooled by means of gas cooling via a special atmosphere, such as an atmosphere of Helium.

[0008] LED filaments are one of most efficient LED light sources on the market, and LED luminaires could benefit from use of LED filaments as a light source. Therefore, LED filaments are now also considered to be used in luminaires.

[0009] However, LED luminaires bring new challenges when incorporating of LED filaments as a light source. It requires additional means to protect the fragile LED filament from mechanical forces during assembly, transportation, installation, and use of such filament-based LED luminaires.

[0010] Also, there are some optical challenges with LED filaments for use in luminaires. These include the following. LED filaments emit light in all directions, while in most cases luminaires, and especially office-compliant luminaires, will require light to be directed into a narrower angular space within a cone less than 71 steradians, or so. Also, LED filaments have quite small and bright light sources which results in significant glare, which might be not appreciated by consumers or will not be accepted in office luminaires as a light source due to not meeting unified glare rating, UGR, specification limits.2025PF80051

[0011] 2

[0012] US 2013 / 141925 Al discloses a low glare overhead lighting fixture for a transit vehicle comprising a lighting fixture base assembly for mounting one or more light sources (e.g., LEDs in the form of a light strip or fluorescent tubes), and a light permeable cover adapted to reduce glare. The light permeable cover may include a light guide embodied as a grid-like structure with holes or perforations for directing the light from the light source in a manner reducing light spread. The light guide may be disposed between front and rear lens covers. The lighting fixture may also utilize a light permeable cover having an anti-glare surface element, such as a privacy filter screen or mesh which may be formed using micro louver technology. The lighting fixture base assembly may have separate compartments, each lined with a highly reflective coating, housing one or more deeply set LEDs.

[0013] It is desired to improve the optical performance of LED filament luminaires, and especially to provide a LED filament arrangement and a LED filament luminaire with a light output having an improved directionality and a reduced glare.

[0014] SUMMARY OF THE INVENTION

[0015] It is an object of the present invention to overcome this problem, and to provide a LED filament arrangement and a luminaire with such a LED filament arrangement, which LED filament arrangement is capable of providing LED filament arrangement light with an improved directionality and a reduced glare, and therefore an improved optical performance.

[0016] According to a first aspect of the invention, this and other objects are achieved by means of a LED filament arrangement configured to, in operation, emit LED filament arrangement light and comprising at least one LED filament, the at least one LED filament being configured to, in operation, emit LED filament light, wherein the at least one LED filament is arranged in a collimator, wherein the collimator (i) is reflective and elongated, (ii) comprises a light exit window, and (iii) is configured to redirect the LED filament light in a direction towards the light exit window, wherein the at least one LED filament arrangement further comprises a plurality of reflecting lamellae arranged in the collimator, and wherein the plurality of reflecting lamellae are arranged extending perpendicular to the LED filament.

[0017] By placing one or more LED filaments in an elongated reflective collimator, it becomes possible to efficiently redirect light into a well-controlled beam. Additionally, providing a set of lamellas allows to achieve light beam control and minimize glare in direction along the filament length. All in all, such a LED filament arrangement provides superior collimated LED filament arrangement light and an improved optical performance.2025PF80051

[0018] 3

[0019] The LED filament arrangement may comprise a plurality of LED filaments, each LED filament of the plurality of LED filaments being configured to, in operation, emit respective LED filament light, wherein each LED filament of the plurality of LED filaments is arranged in a respective associated collimator, wherein each collimator (i) is reflective and elongated, (ii) comprises a respective associated light exit window, and (iii) is configured to redirect the LED filament light in a direction towards the light exit window, wherein each collimator further comprises a plurality of respective associated reflecting lamellae, each plurality of reflecting lamellae being arranged extending perpendicular to the LED filament arranged in the collimator.

[0020] Thereby an improved light quality and efficiency, and thus an improved optical performance, is provided for.

[0021] The LED filament arrangement light may be white light having a correlated color temperature in a range from 1700K to 6500K and / or a color rendering index of at least 80.

[0022] The LED filament light may be white light having a correlated color temperature in a range from 1700K to 6500K and / or a color rendering index of at least 80.

[0023] At least one of the collimator and the plurality of reflecting lamellae may be specularly reflecting.

[0024] At least one of each collimator and each plurality of reflecting lamellae may be specularly reflecting.

[0025] This provides further improved collimation and focusing and thus directionality of the LED filament light in a predefined direction, and thus improved accuracy of the achieved beam shape of the LED filament arrangement light.

[0026] The at least one LED filament may be arranged in an optical center of the collimator.

[0027] Each LED filament of the plurality of LED filaments may be arranged in an optical center of a collimator.

[0028] The obtained effect is even further improved collimation because it in this way is ensured that the majority of the LED filament arrangement light is indirect light, that is majority of the LED filament light is projected towards the reflector.

[0029] The at least one LED filament may comprise a substrate with a first major surface, and a second major surface opposite to the first major surface, wherein the at least one LED filament comprises an array of LED light sources arranged on the first major2025PF80051

[0030] 4

[0031] surface, and wherein the at least one LED filament is arranged in the collimator in such a way that the array of LED light sources face a bottom part of the collimator.

[0032] Alternatively, the at least one LED filament may comprise a substrate with a first major surface, and a second major surface opposite to the first major surface, wherein the at least one LED filament comprises a first array of LED light sources arranged on the first major surface and a second array of LED light sources arranged on the second major surface, and wherein the at least one LED filament is arranged in the collimator in such a way that the first array of LED light sources and the second array of LED light sources face mutually opposite side parts of the collimator.

[0033] Each LED filament of the plurality of LED filaments may comprise a substrate with a first major surface, and a second major surface opposite to the first major surface, wherein at least one LED filament of the plurality of LED filaments comprises an array of LED light sources arranged on the first major surface, and wherein the at least one LED filament of the plurality of LED filaments is arranged in the collimator in such a way that the array of LED light sources face a bottom part of the collimator.

[0034] Alternatively, each LED filament of the plurality of LED filaments may comprise a substrate with a first major surface, and a second major surface opposite to the first major surface, wherein at least one LED filament of the plurality of LED filaments comprises a first array of LED light sources arranged on the first major surface and a second array of LED light sources arranged on the second major surface, and wherein the at least one LED filament of the plurality of LED filaments is arranged in the collimator in such a way that the first array of LED light sources and the second array of LED light sources face mutually opposite side parts of the collimator.

[0035] Thereby, a LED filament arrangement with a simple structure and improved collimation of the arrangement light is provided since the LED filament light is directed directly towards the collimator.

[0036] The plurality of reflecting lamellae and the at least one LED filament may be one or more of mechanically attached to one another and thermally connected to one another.

[0037] Each plurality of reflecting lamellae may be one or more of mechanically attached and thermally connected to the LED filament arranged in the same collimator.

[0038] The at least one LED filament and the collimator may be one or more of mechanically attached to one another and thermally connected to one another.

[0039] Each LED filament of the plurality of LED filaments may be one or more of mechanically attached and thermally connected to the collimator in which it is arranged.2025PF80051

[0040] 5

[0041] Mechanical attachment provides improved rigidity of LED filament arrangement. Mechanical attachment between LED filaments and collimator further keeps the LED filaments in the desired position in a particularly simple manner and can support cooling of LED filaments. Sufficient mechanical fixation between lamellae and LED filament (and / or LED filament and reflector), as well as between lamellae and reflector, further provides rigidity to the LED filament arrangement and mechanical protection to LED filament(s).

[0042] Thermal connection provides improved cooling of the LED filaments.

[0043] Sufficient cooling of the LED filaments may be required to ensure long-term operation, especially since the LED filament’s own outer surface often is insufficiently small for effective cooling by air. Keeping the LED filament temperature low is in any event essential not only for lifetime, but also for improved efficiency in application since LED efficiency is negatively affected by elevated temperatures. Furthermore, if the lamellae have good mechanical contact to the outer surface of the LED filament(s) and are made out of metal sheets or other thermally conductive materials, it will help to improve cooling of LED filament within such modular light source element to air and avoid use of a dedicated cooling atmosphere of for instance Helium.

[0044] A spacing may be provided between the at least one LED filament and at least one lamella of the plurality of reflecting lamellae.

[0045] A spacing may be provided between at least one LED filament of the plurality of LED filaments and at least one lamella of the plurality of reflecting lamellae arranged in the same collimator.

[0046] The spacing is at most 1 mm, at most 0.75 mm, or at most 0.5 mm.

[0047] Thereby, a good compromise between rigidity and flexibility and the advantages associated with each of these is obtained.

[0048] A spacing may be provided between the at least one LED filament and the collimator.

[0049] A spacing may be provided between at least one LED filament of the plurality of LED filaments and the collimator in which it is arranged.

[0050] Thereby, an improved light guidance and thus light quality is obtained.

[0051] At least one lamella of the plurality of reflecting lamellae may comprise two parts, wherein one or more of the following applies: (i) the at least one LED filament is arranged between the two parts, and (ii) at least one of the two parts comprises a recess2025PF80051

[0052] 6

[0053] configured to enable arranging the at least one LED filament at least partly recessed in the recess.

[0054] At least one lamella of each plurality of reflecting lamellae may comprise two parts, wherein one or more of the following applies: (i) a LED filament of the plurality of LED filaments is arranged between the two parts, and (ii) at least one of the two parts comprises a recess configured to enable arranging a LED filament of the plurality of LED filaments at least partly recessed in the recess.

[0055] The plurality of reflecting lamellae may comprise through holes, wherein the at least one LED filament is arranged in the through holes. The lamella may fully surround the respective through hole, and may hence fully encircle the inserted LED filament.

[0056] Each plurality of reflecting lamellae may comprise through holes, wherein a LED filament of the plurality of LED filaments is arranged in the through holes.

[0057] Fixing the LED filament within an opening or through hole in the lamellae and combining this with a shaped elongated reflector will provide mechanical stiffness and rigidity to the whole LED filament arrangement such as to protect the rather fragile LED filament(s) from breaking during assembly, transportation, and use.

[0058] At least one lamella of the plurality of reflecting lamellae may be arranged at only one side of the at least one LED filament.

[0059] At least one lamella of each plurality of reflecting lamellae may be arranged at only one side of the respective LED filament of the plurality of LED filaments.

[0060] Thereby, the glare in the direction of curvature of the lamella is limited.

[0061] A surface of at least one lamella of the plurality of reflecting lamellae adjacent to the at least one LED filament may be shaped such that at least a part of the lamella is provided with the shape of a wedge tapering away from the LED filament.

[0062] A surface of at least one lamella of each plurality of reflecting lamellae adjacent to the respective LED filament of the plurality of LED filaments may be shaped such that at least a part of the lamella is provided with the shape of a wedge tapering away from the respective LED filament of the plurality of LED filaments.

[0063] Thereby, light from the part of the filament under the base of the lamella or lamellae will be blocked. To limit the light loss, the filament architecture can be optimized by ensuring that no LED light sources are placed at those parts of the LED filament(s) as will be described below.

[0064] The at least one LED filament may be free from LED light sources at a position directly adjacent to the plurality of lamellae.2025PF80051

[0065] 7

[0066] At least one LED filament of the plurality of LED filaments may be free from LED light sources at a position directly adjacent to the plurality of lamellae arranged in the same collimator.

[0067] The at least one LED filament may be free from LED light sources in segments, which in an assembled condition of the LED filament arrangement are arranged directly adjacent to the plurality of lamellae.

[0068] At least one LED filament of the plurality of LED filaments may be free from LED light sources in segments, which in an assembled condition of the LED filament arrangement are arranged directly adjacent to the plurality of lamellae arranged in the same collimator.

[0069] Providing the LED filament(s) with LED light source free segments and / or positions as described above will improve optical efficiency of the LED filament arrangement, since locally there will be no light emission from LED filament to the directly adjacent portion of the lamellae, and light losses will be minimized.

[0070] At least one lamella of the plurality of reflecting lamellae may comprise a base configured to be positioned directly adjacent to the at least one LED filament, wherein at least the base is transparent.

[0071] At least one lamella of each plurality of reflecting lamellae may comprise a base configured to be positioned directly adjacent to the LED filament of the plurality of LED filaments arranged in the same collimator, wherein at least the base is transparent.

[0072] At least a part of at least one lamella of the plurality of reflecting lamellae may comprise a reflective coating, a reflective foil, or a reflective layer.

[0073] At least a part of at least one lamella of each plurality of reflecting lamellae may comprise a reflective coating, a reflective foil, or a reflective layer.

[0074] Providing lamellae being transparent or reflective will limit loss of light by absorption in lamellae.

[0075] The collimator may comprise a first collimator part and a second collimator part, wherein the first collimator part and the second collimator part comprise mutually different shapes.

[0076] Each collimator may comprise a first collimator part and a second collimator part, wherein the first collimator part and the second collimator part comprise mutually different shapes.

[0077] This makes further improved collimation and further embodiments and shapes of LED filament arrangements possible.2025PF80051

[0078] 8

[0079] The collimator, or the second collimator part of the collimator, may be a parabolic reflector, or a reflector shaped as a small letter omega, co, or a m-shaped reflector.

[0080] Each collimator, or the second collimator part of each collimator, may be a parabolic reflector, or a reflector shaped as a small letter omega, co, or a m-shaped reflector.

[0081] This makes further improved collimation and further embodiments of LED filament arrangements possible.

[0082] The LED filament arrangement may further comprise a controller configured to control the at least one LED filament.

[0083] The LED filament arrangement may further comprise a controller configured to individually control each LED filament of the plurality of LED filaments.

[0084] Providing such a controller allows for beam shaping and beam control such as collimation control. Providing such a controller also allows for controlling light parameters of the LED filament light such as correlated color temperature, CCT, and color rendering index, CRI.

[0085] The at least one LED filament may comprise a substrate, wherein the substrate may comprise one or more of the following: (i) mutually opposite end sections being free from LED light sources and configured to, in an assembled condition of the LED filament arrangement, extend into or be attached to the collimator, (ii) local or continuous extensions configured to, in an assembled condition of the LED filament arrangement, extend towards a lamella of the plurality of lamellae, (iii) a local or continuous extension configured to, in an assembled condition of the LED filament arrangement, extend towards the collimator, and (iv) a first major surface and a second major surface opposite to the first major surface, and a luminescent encapsulant arranged on one or both major surfaces of the substrate. The substrate may be a light-transmissive substrate.

[0086] At least one LED filament of the plurality of LED filaments may comprise a substrate, wherein the substrate may comprise one or more of the following: (i) mutually opposite end sections being free from LED light sources and configured to, in an assembled condition of the LED filament arrangement, extend into or be attached to a collimator, (ii) local or continuous extensions configured to, in an assembled condition of the LED filament arrangement, extend towards a lamella of a plurality of lamellae, (iii) a local or continuous extension configured to, in an assembled condition of the LED filament arrangement, extend towards a collimator, and (iv) a first major surface and a second major surface opposite to the first major surface, and a luminescent encapsulant arranged on one or both major surfaces of the substrate. The substrate may be a light-transmissive substrate.2025PF80051

[0087] 9

[0088] Providing mutually opposite end sections being free from LED light sources enables a further improved heat transfer from the LED filament(s) to the collimator is achieved.

[0089] Providing local or continuous extensions allows for simpler fixation and enables sufficient heat transfer from LED filament to lamellas for improved cooling.

[0090] Providing a luminescent element enables providing improved white LED filament arrangement light in terms of one or more of CCT and CRI.

[0091] The collimator and / or the second part of the collimator may comprise a reflective foil or a reflective coating or a reflective layer on a surface facing the plurality of LED filaments.

[0092] Thereby, a collimator, and thus a LED filament arrangement, with a simple construction is provided for.

[0093] The collimator and / or the second part of the collimator may be one or more of molded and shaped in one piece.

[0094] Thereby, the mechanical stability is improved even further.

[0095] The plurality of reflecting lamellae may be made of or comprise a heat conductive material, such as a metal.

[0096] Thereby, improved cooling of the LED filament(s) is provided for.

[0097] The plurality of LED filaments may be rigid or flexible.

[0098] The plurality of LED filaments may comprise a light transparent outer cover. Such a cover serves to protect the LED filaments from mechanical damages during assembly of the LED filaments, the collimator, and the lamellae. Also, such a cover may protect the LED filaments during transportation and use.

[0099] The transparent outer cover may comprise light scattering particles.

[0100] Such particles serve to hide a yellow appearance of the LED filaments, and additionally to reduce the brightness of the light emitting surface of the LED filaments, thereby reducing glare.

[0101] The LED filament arrangement may comprise a light exit window and a light diffusing or light beam shaping optical element arranged at the light exit window.

[0102] Thereby, the visual appearance and comfort of such a LED filament arrangement is further improved.

[0103] The lamellae may each comprise a length, LI, a width, Wl, and a height, Hl. The length, LI, of the lamellae may be in a range from 3 mm to 30 mm. The height, Hl, of the2025PF80051

[0104] 10

[0105] lamellae may be in a range from 3 mm to 30 mm. The width, Wl, of the lamellae may be in a range from 0.1 mm to 1 mm.

[0106] The collimator may comprise a length, Lc, a width, Wc, and a height, He. The height, He, of the collimator may be in a range from 3 mm to 30 mm. The width, Wc, of the collimator may be in a range from 3 mm to 30 mm. The length, Lc, of the collimator may be at least 30 mm, or at least 60 mm.

[0107] Each, or at least one, of the LED filaments may comprise a length, Lf, a width, Wf, and a thickness or diameter, Df. The length, Lf, of each, or the at least one, LED filament may be at least 30 mm, or at least 60 mm. The width, Wf, of each, or the at least one, LED filament may be in a range from 1 mm to 5 mm. The thickness or diameter, Df, of each, or the at least one, LED filament may be in a range from 1 mm to 5 mm.

[0108] The invention further relates to a luminaire comprising at least one LED filament arrangement according to the invention.

[0109] The luminaire may be a modular luminaire. The luminaire may comprise at least two modules configured to be assembled, for instance by a snap-locking or a frictionlocking mechanism. At least one module of the at least two modules is a LED filament arrangement according to the invention comprising at least one LED filament.

[0110] The luminaire may be any type of luminaire, and in particular any type of luminaire for directional lighting, such as panels, pendants, troffers, (trunking) line fixtures, standing luminaires, wall hung luminaires, a chandeliers, reading luminaires, outdoor luminaires, and table luminaires. Often, the luminaire at least comprises electrical contacting means to a power supply, such as a terminal block, and means to hold and / or (partly) accommodate the at least one LED filament arrangement, such as a housing.

[0111] It is noted that the invention relates to all possible combinations of features recited in the claims.

[0112] BRIEF DESCRIPTION OF THE DRAWINGS

[0113] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

[0114] Fig. 1 shows a perspective view of a LED filament arrangement according to the invention and comprising a LED filament, a first reflective collimator, and a first plurality of reflecting lamellae.

[0115] Fig. 2 shows a cross-sectional side view of the LED filament arrangement according to Fig. 1.2025PF80051

[0116] 11

[0117] Fig. 3 shows a graph illustrating an example of a target light distribution from LED filament arrangement according to Figs. 1-2.

[0118] Fig. 4 shows a perspective view of an alternative embodiment of a lamella of a LED filament arrangement according to the invention.

[0119] Figs. 5 and 6 shows further cross-sectional side views of the LED filament arrangement according to Fig. 1 but showing different embodiments of the reflecting collimator.

[0120] Figs. 7A and 7B show further cross-sectional side views of the LED filament arrangement according to Fig. 1 but showing different embodiments of a LED filament of the plurality of LED filaments.

[0121] Fig. 8 shows a bottom view of another LED filament arrangement according to the invention, and comprising a first and a second LED filament, a first and a second reflective collimator, and a first and a second plurality of reflecting lamellae.

[0122] Fig. 9 shows a cross-sectional side view of the LED filament arrangement according to Fig. 8 taken at the line IX in Fig. 8 and showing a lamella.

[0123] Fig. 10 shows a cross-sectional side view of the LED filament arrangement according to Fig. 8 taken at the line X in Fig. 8.

[0124] Figs. 11 to 14 shows further exemplary cross-sectional side views of the LED filament arrangement according to Fig. 8 taken at the line IX in Fig. 8 but showing different embodiments of the lamella.

[0125] Fig. 15 shows a cross-sectional side view of another LED filament arrangement according to the invention.

[0126] Fig. 16 shows a cross-sectional side view of another LED filament arrangement according to the invention.

[0127] Fig. 17 shows a cross-sectional side view of another LED filament arrangement according to the invention.

[0128] Fig. 18 shows a cross-sectional side view of another LED filament arrangement according to the invention.

[0129] Figs. 19-21 show schematical views of three different luminaires, each comprising a LED filament arrangement according to the invention.

[0130] As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.2025PF80051

[0131] 12

[0132] DETAILED DESCRIPTION

[0133] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0134] Fig. 1 shows a perspective view of a LED filament arrangement 1 according to the invention. Fig. 2 shows a cross-sectional side view of the LED filament arrangement 1. Generally, and irrespective of the embodiment, the LED filament arrangement 1 comprises a LED filament 31, a first reflective collimator 51, and a first plurality of reflecting lamellae 71. The LED filament arrangement 1 is configured to, in operation, emit LED filament arrangement light 2.

[0135] The LED filament 31 is configured to, in operation, emit LED filament light 41. The LED filament 31 is arranged in the collimator 51. The LED filament 31 may be arranged in an optical center, C, of the collimator 51. The LED filament 31 may be rigid or flexible. The LED filament 31 and the collimator 51 may be mechanically attached to one another. Alternatively, or additionally, the LED filament 31 and the collimator 51 may be thermally connected to one another.

[0136] Referring also to Fig. 8, the LED filament 31 comprises a length, Lf, a width, Wf, and a thickness or diameter, Df. The length, Lf, of the LED filament 31 may be at least 30 mm, or at least 60 mm. The width, Wf, of the LED filament 31 may be in a range from 1 mm to 5 mm. The thickness or diameter, Df, of the LED filament 31 may be in a range from 1 mm to 5 mm.

[0137] The collimator 51 is reflective and elongated. The collimator 51 comprises a longitudinal direction or axis AL (cf. Fig. 1) and a transversal direction or axis AT (cf. Fig.

[0138] 2). The collimator 51 comprises a light exit window 61. The collimator 51 is configured to redirect the LED filament light 41 in a direction towards the light exit window 61. The collimator 51 may comprise a reflective foil or a reflective coating or a reflective layer on a surface 56 (cf. Fig. 2) facing the LED filament 31. The collimator 51 may be molded. The collimator 51 may be shaped in one piece. The collimator 51 is as shown in Fig. 1 a reflector shaped as a small letter omega, co. Alternatively, the collimator 51 may be a m-shaped reflector. The collimator 51 may be specularly reflecting.2025PF80051

[0139] 13

[0140] Referring also to Fig. 8, the collimator 51 comprises a length, Lc, a width, Wc, and a height, He. The height, He, of the collimator 51 may be in a range from 3 mm to 30 mm. The width, Wc, of the collimator 51 may be in a range from 3 mm to 30 mm. The length, Lc, of the collimator 51 may be at least 30 mm, or at least 60 mm.

[0141] As illustrated in Fig. 2, the LED filament arrangement 1 further comprises an optional optical element 8. The optical element 8 is a light diffusing or light beam shaping optical element. The optical element 8 is arranged at the light exit window 61.

[0142] The plurality of reflecting lamellae 71 is arranged in the collimator 51. The plurality of reflecting lamellae 71 is arranged extending perpendicular to the LED filament 31. The plurality of reflecting lamellae 71 is arranged such that each lamella extends perpendicular to the LED filament 31. For instance, the LED filament 31 is arranged extending along the longitudinal direction AL of the collimator 51, and each lamella of the plurality of reflecting lamellae 71 is arranged extending along the transversal direction AT of the collimator 51. The plurality of reflecting lamellae 71 may be made of or comprise a heat conductive material, such as a metal. At least a part of at least one lamella of the plurality of reflecting lamellae 71 may comprise a reflective coating, a reflective foil, or a reflective layer. The plurality of reflecting lamellae 71 may be specularly reflecting. The plurality of reflecting lamellae 71 and the LED filament 31 may be mechanically attached to one another. Alternatively, or additionally, the plurality of reflecting lamellae 71 and the LED filament 31 may be thermally connected to one another.

[0143] Referring also to Fig. 8, each lamella of the plurality of lamellae 71 comprises a thickness, Tl, a width, Wl, and a height, Hl. The width, Wl, of the lamellae may be in a range from 3 mm to 30 mm. The height, Hl, of the lamellae may be in a range from 3 mm to 30 mm. The thickness, Tl, of the lamellae may be in a range from 0.1 mm to 1 mm.

[0144] As is best seen in Fig. 2, the lamellae of the plurality of lamellae 71 of the light emitting device 1 extend from the light exit window 61 of the collimator 51 to about level with a center of the LED filament 31. The lamellae of the plurality of lamellae 71 of the light emitting device 1 comprises a height Hl which is smaller than, and more particularly about half of, the height He of the collimator 51, 52.

[0145] The LED filament arrangement 1 further comprises a controller 13 (cf. Fig. 1). The controller 13 is configured to control the LED filament 31.

[0146] Fig. 3 shows a graph illustrating an example of a target LED filament arrangement light distribution from LED filament arrangement 1 according to Fig. 1. Fig. 3 indicates the light distribution perpendicular to the longitudinal axis of the LED filament2025PF80051

[0147] 14

[0148] arrangement (C90-C270) and the light distribution in direction of the longitudinal axis of the LED filament arrangement (C0-C180). As may be seen, the LED filament arrangement light comprises an improved directionality. Therefore, the LED filament arrangement 1 described above exhibits an improved optical performance.

[0149] Fig. 4 shows a perspective view of an alternative embodiment of a lamella 71 of a plurality of lamellae 71 of a LED filament arrangement according to the invention.

[0150] The lamella 71 comprises a surface 77. The surface 77 of the lamella 71 is, at least adjacent to the LED filament 31, shaped such that at least a part of the lamella 71 is provided with the shape of a wedge which tapers away from the LED filament 31. One or more lamellae of the plurality of lamellae 71, or of each plurality of reflecting lamellae 71, 72, may be shaped in this way.

[0151] Furthermore, the lamella 71 comprises a base 78. The base 78 is configured to be positioned directly adjacent to the LED filament 31. At least the base 78 of the lamella 71 is transparent.

[0152] Irrespective of the embodiment, the LED filament 31 may be free from LED light sources 33, 34 at a position directly adjacent to the lamella 71. The LED filament 31 comprises a segment 35 which in an assembled condition of the LED filament arrangement 1 is arranged directly adjacent to the lamella 71. The segment 35 may be free from LED light sources 33, 34.

[0153] Figs. 5 and 6 shows further cross-sectional side views of the LED filament arrangement 1 according to Fig. 1 but showing two different variants of the reflecting collimator.

[0154] Fig. 5 shows a variant in which the LED filament 31 is arranged close to or touching the collimator 51. Especially, the collimator 51 comprises a surface segment 57 configured for being in contact with or receiving the LED filament 31. The surface segment 57 is arranged at the bottom 53 of the collimator 51 at a center of symmetry CS of the collimator 51. The surface segment 57 may comprise a shape conforming to or almost conforming to the outer surface of the LED filament 31. Positioning the LED filament 31 in this way ensures good focusing of the LED filament light in a predefined direction. Thereby a more accurate beam shape of the LED filament arrangement light is obtained. Additionally, arranging the LED filament 31 touching the surface segment 57, or the reflector 51, may enhance the cooling of the LED filament 31 via heat transfer into the collimator 51.

[0155] Fig. 6 shows a variant in which the LED filament 31 is arranged in a distance d2 from the collimator 51. A spacing 10 is formed between the LED filament 31 and the2025PF80051

[0156] 15

[0157] collimator 51. In addition to the surface segment 57 described above, the collimator 51 to this end comprises an extension 58. The extension 58 is arranged extending between the bottom 53 of the collimator 51 and the surface segment 57. Thereby an improved optical efficiency of the LED filament arrangement 1 and / or other shapes of the beam as compared to the variant shown in Fig. 5 may be obtained. Preferably, the distance d2 is chosen such that the LED filament 31 is arranged in the optical center C of the collimator 51.

[0158] Fig. 7A shows a further cross-sectional side view of the LED filament arrangement 1 according to Fig. 1 but showing a different embodiment of the LED filament 31.

[0159] The LED filament 31 comprises a substrate 36 and a first array of LED light sources 33. The first array of light sources 33 is arranged on one of the mutually opposite major surfaces 361 and 362 of the substrate 36, as shown in Fig. 7A on the major surface 361. The LED filament 31 is arranged in the collimator 51 in such a way that the first array of LED light sources 33 face one of the mutually opposite side parts 54, 55 of the collimator 51 as shown in Fig. 7 A the side part 55.

[0160] The LED filament 31 is again arranged in a distance d2 from the collimator 51. A spacing 10 is formed between the LED filament 31 and the collimator 51. To this end, the substrate 36 comprises a local or continuous extension 367. The extension 367 is configured to, in an assembled condition of the LED filament arrangement 1, extend towards the collimator 51.

[0161] The LED filament 31 further comprises a luminescent encapsulant 14, 15. As shown on Fig. 7A, the luminescent encapsulant 14, 15 is arranged on both major surfaces 31, 32 of the substrate 36. It is also feasible that the luminescent encapsulant is arranged on only the one of the major surfaces 31, 32 of the substrate 36 on which the first array of light sources 33 is arranged. The substrate 36 may be a light-transmissive substrate.

[0162] Fig. 7B shows a further cross-sectional side view of the LED filament arrangement 1 according to Fig. 1 but showing a different embodiment of the LED filament 31.

[0163] The LED filament 31 comprises a substrate 36, a first array of LED light sources 33 and a second array of LED light sources 34. The first and second array of light sources 33 and 34 are arranged on mutually opposite major surfaces 361 and 362 of the substrate 36. The LED filament 31 is arranged in the collimator 51 in such a way that the first array of LED light sources 33 and the second array of LED light sources 34 face mutually opposite side parts 54, 55 of the collimator 51.2025PF80051

[0164] 16

[0165] The LED filament 31 is again arranged in a distance d2 from the collimator 51. A spacing 10 is formed between the LED filament 31 and the collimator 51. To this end, the substrate 36 comprises a local or continuous extension 367. The extension 367 is configured to, in an assembled condition of the LED filament arrangement 1, extend towards the collimator 51.

[0166] The LED filament 31 further comprises a luminescent encapsulant 14, 15. In the embodiment shown, the luminescent encapsulant 14, 15 is arranged on both major surfaces 31, 32 of the substrate 36.

[0167] Such a LED filament 31 may for instance be made by taking two LED filaments, each with only an array of LED light sources 33 arranged on the first major surface 361, and attach, such as glue, them together back to back. Alternatively, such a LED filament 31 may for instance be made by folding a metal strip having two rows of LED light sources such that one row of LED light sources form the first array of LED light sources 33 and the other row of LED light sources form the second array of LED light sources 34.

[0168] Fig. 8 shows a bottom view of another LED filament arrangement 100 according to the invention. Fig. 9 shows a cross-sectional side view of the LED filament arrangement 100 taken at the line IX in Fig. 8 and showing a lamella. Fig. 10 shows a cross-sectional side view of the LED filament arrangement 100 taken at the line X in Fig. 8, where no lamella is present. The LED filament arrangement 100 shown in Figs. 3-5 differs from the LED filament arrangement 1 shown in Figs. 1 and 2 and described above in virtue of the following features.

[0169] The LED filament arrangement 100 comprises a plurality of LED filaments 31, 32. In the embodiment shown, two LED filaments 31, 32 are shown, although more than two LED filaments may also be provided. Each LED filament of the plurality of LED filaments 31, 32 is configured to, in operation, emit LED filament light 41, 42 (cf. Fig. 9). Each LED filament of the plurality of LED filaments 31, 32 is arranged in a collimator 51, 52. Each LED filament of the plurality of LED filaments 31, 32 may be arranged in an optical center C of a respective collimator 51, 52. Each LED filament of the plurality of LED filaments 31, 32 may be mechanically attached to the collimator 51, 52 in which it is arranged. Alternatively, or additionally, each LED filament of the plurality of LED filaments 31, 32 may be thermally connected to the collimator 51, 52 in which it is arranged.

[0170] Therefore, the LED filament arrangement 100 also comprises a plurality of collimators 51, 52. As shown in Fig. 8, two collimators 51, 52 are shown, although more than two collimators may also be provided. The two collimators 51 and 52 are identical in shape.2025PF80051

[0171] 17

[0172] Each collimator 51, 52 is reflective and elongated. Each collimator 51, 52 comprises a light exit window 61, 62. Each collimator 51, 52 is configured to redirect the LED filament light 41, 42 in a direction towards the respective light exit window 61, 62. As shown in Figs. 9 and 10, each collimator 51, 52 is a parabolic reflector.

[0173] Each collimator 51, 52 further comprises a plurality of reflecting lamellae 71, 72. In the embodiment shown, two pluralities of reflecting lamellae 71, 72 are shown, although more than two pluralities of reflecting lamellae may also be provided. The lamellae of each plurality of lamellae 71, 72 are arranged extending perpendicular to the respective LED filament 31, 32 arranged in the respective collimator 51, 52. Each plurality of reflecting lamellae 71, 72 may be specularly reflecting. Each plurality of reflecting lamellae 71, 72 may be mechanically attached to the LED filament 31, 32 arranged in the same collimator 51, 52. Alternatively, or additionally, each plurality of reflecting lamellae 71, 72 may be thermally connected to the LED filament 31, 32 arranged in the same collimator 51, 52.

[0174] As is best seen in Fig. 9, the lamellae of each plurality of lamellae 71, 72 fills the entire cross section of the collimator 51, 52, except for where the LED filament 31, 32 passes through the lamella. Thus, the lamellae of each plurality of lamellae 71, 72 comprises a height Hl which is equal to the height He of the collimator 51, 52.

[0175] Figs. 11 to 14 shows further exemplary cross-sectional side views of the LED filament arrangement according to Fig. 8 taken at the line IX in Fig. 8 but showing different embodiments of a lamella of each plurality of reflecting lamellae 71,72.

[0176] As shown in Fig. 11, each lamellae of each plurality of reflecting lamellae 71, 72, comprise through holes 73 for inserting a LED filament of the plurality of LED filaments 31, 32. Each lamella 71,72 may fully surround the respective through hole73, and may hence fully surround the inserted LED filament. Furthermore, a spacing 9 is provided between the respective LED filament 31, 32 and the respective lamella 71, 72 arranged in the same collimator. The spacing 9 may be less than 2 mm. Also, a spacing 10 is provided between the respective LED filament 31, 32 and the collimator 51, 52 in which it is arranged.

[0177] As shown in Fig. 12, at least one lamella of each plurality of reflecting lamellae 71, 72 comprises two parts 74, 75. The respective LED filament of the plurality of LED filaments 31, 32 is then arranged between the two parts 74, 73. At least one, or as shown in Fig. 12 both, of the two parts 74, 75 may then comprise a recess 76. The recess 76 is configured to enable arranging a LED filament of the plurality of LED filaments 31, 32 at least partly recessed in the recess 76.2025PF80051

[0178] 18

[0179] As shown in Figs. 13 and 14, each lamella of each plurality of reflecting lamellae 71, 72 is arranged at only one side of the respective LED filament of the plurality of LED filaments 31, 32. As shown in Fig. 13, each lamella of each plurality of reflecting lamellae 71, 72 is arranged extending from a bottom part 53 of the respective collimator 51, 52 to about level with an optical center C of the collimator 51, 52, and thus only at a lower side of the respective LED filament of the plurality of LED filaments 31, 32. As shown in Fig. 14, each lamella of each plurality of reflecting lamellae 71, 72 is arranged extending from the light exit window 61, 62 of the respective collimator 51, 52 to about level with an optical center C of the collimator 51, 52, and thus only at an upper side of the respective LED filament of the plurality of LED filaments 31, 32.

[0180] Referring again to Fig. 8, each LED filament of the plurality of LED filaments 31, 32 comprises a substrate 36. The substrate 36 comprises mutually opposite end sections 363, 364. The mutually opposite end sections 363, 364 are free from LED light sources 33, 34 (cf. Fig. 15). The mutually opposite end sections 363, 364 are configured to, in an assembled condition of the LED filament arrangement 100, extend into or be attached to a collimator 51, 52.

[0181] The controller 13 of the light emitting device 100 is configured to individually control each LED filament of the plurality of LED filaments 31, 32.

[0182] Fig. 15 shows a cross-sectional side view of a LED filament arrangement 101 according to the invention. The LED filament arrangement 101 illustrates a number of features which are not described in relation to Figs. 1 to 14 above, but which may apply to any LED filament arrangement according to the present invention.

[0183] Each LED filament 31, 32 comprises a substrate 36. The substrate 36 comprises a first major surface 361, and a second major surface 362 opposite to the first major surface 361.

[0184] Generally, a LED filament 31, 32 of a light generating device according to the present invention comprises at least one array of LED light sources 33, 34. The at least one array of LED light sources 33, 34 is configured to, in operation emit LED light source light.

[0185] As a first example, see the right hand side of Fig. 15, the LED filament 32 comprises an array of LED light sources 33 arranged on the first major surface 361 (as shown) or the second major surface 362. The LED filament 32 is arranged in the collimator 52 in such a way that the array of LED light sources 33 face a bottom part 53 of the collimator 52.2025PF80051

[0186] 19

[0187] As a second example, see the left hand side of Fig. 15, the LED filament 31 comprises a first array of LED light sources 33 arranged on the first major surface 361 of the substrate 36 and a second array of LED light sources 34 arranged on the second major surface 362 of the substrate 36. The LED filament 31 is arranged in the collimator 51 in such a way that the first array of LED light sources 33 a bottom part 53 of the collimator 51 and the second array of LED light sources 34 face the light exit window 61. Such a LED filament 31 may for instance be made by taking two LED filaments, each with only an array of LED light sources 33 arranged on the first major surface 361, and attach, such as glue, them together back to back. Alternatively, such a LED filament 31 may for instance be made by folding a metal strip having two rows of LED light sources such that one row of LED light sources form the first array of LED light sources 33 and the other row of LED light sources form the second array of LED light sources 34.

[0188] The substrate 36 may further comprise local or continuous extensions 365, 366, see the right hand side of Fig. 15. The local or continuous extensions 365, 366 are configured to, in an assembled condition of the LED filament arrangement 101, extend towards a lamella of the plurality of lamellae 71, 72.

[0189] The LED filaments 31, 32 may further comprise a light transparent outer cover 37. The transparent outer cover 37 may comprise light scattering particles.

[0190] As shown in Fig. 15, the two collimators 51 and 52 have different shapes. The collimator 51 is hemispherical in cross-sectional shape. The collimator 52 is hemi-elliptical in cross-sectional shape.

[0191] Fig. 16 shows a cross-sectional view of another LED filament arrangement 102 according to the invention. The LED filament arrangement 102 differs from the LED filament arrangements 1, 100 and 101 shown in Figs. 1 to 15 and described above in virtue of the following features.

[0192] The collimator 51 comprises a first collimator part 11 and a second collimator part 12. The first collimator part 11 and the second collimator part 12 comprise mutually different shapes. The second collimator part 12 of the collimator 51 is shaped as a small letter omega, co, or a m-shaped reflector. The plurality of lamellae 71 are mounted or integrated in the first collimator part 11. The first collimator part 11 of the collimator 51 may but need not be a parabolic reflector.

[0193] Such a collimator 51 provides for a LED filament arrangement which is easy to assemble, that is easy to assemble. In more detail, one first mounts the second collimator part 12, then one mounts the LED filament(s) 31 in the second collimator part 12, and finally2025PF80051

[0194] 20

[0195] one attaches the first collimator part 11 with the integrated plurality of lamellae 71 to the second collimator part 12.

[0196] Fig. 17 shows a cross-sectional view of another LED filament arrangement 103 according to the invention. The LED filament arrangement 103 differs from the LED filament arrangements 1, 100, 101 and 102 shown in Figs. 1 to 16 and described above in virtue of the following features.

[0197] The LED filament arrangement 103 comprises a plurality of reflectors 51, a plurality of pluralities of reflecting lamellae 71, and a plurality of LED filaments 31. More particularly eight reflectors 51, eight pluralities of reflecting lamellae 71, and eight LED filaments 31 are provided, although other numbers lower or higher than eight are also feasible. The reflectors 51, and therefore also the pluralities of lamellae 71 and the LED filaments 31, are arranged in a circular formation with their respective longitudinal axes pointing toward a common center. The LED filament arrangement 103 may be described as an assembly of eight LED filament arrangements 1 of the type described above and shown in Figs. 1 and 2.

[0198] Fig. 18 shows a cross-sectional view of another LED filament arrangement 104 according to the invention. The LED filament arrangement 104 differs from the LED filament arrangements 1, 100, 101, 102 and 103 shown in Figs. 1 to 17 and described above in virtue of the following features.

[0199] The LED filament arrangement 104 comprises a plurality of reflectors 51, 52, a plurality of pluralities of reflecting lamellae 71, 72, and a plurality of LED filaments 31, 32. More particularly eight reflectors 51, 52, eight pluralities of reflecting lamellae 71, 52, and eight LED filaments 31, 32 are provided, although other numbers lower or higher than eight are also feasible. The reflectors 51, 52, and therefore also the pluralities of lamellae 71, 72 and the LED filaments 31, 32, are arranged in a side-by-side formation, or in parallel, with their respective longitudinal axes extending parallel to one another. The LED filament arrangement 104 may be described as an assembly of four LED filament arrangements 100 of the type described above and shown in Fig. 8.

[0200] Turning now to Fig. 19, an exemplary luminaire in the form of a downlight pendant 400 is shown. The pendant 400 comprises a plurality of LED filament arrangements 1, 100, 101, 102, 103, 104 according to any embodiment of the invention. In the embodiment shown, the pendant 400 comprises a plurality of LED filament arrangements 1 of the type shown in Figs. 1 and 2 being connected in series.2025PF80051

[0201] 21

[0202] The pendant 400 further comprises an electrical connection element 401, such as a socket or another suitable electrical connection element for connecting the plurality of LED filament arrangements 1, 100, 101, 102, 103, 104, to the pendant 400. The electrical connection element 401 may be adapted to cooperate with an electrical outlet of the plurality of LED filament arrangements 1, 100, 101, 102, 103, 104. The pendant 400 further comprises a mechanical connection element 406. The mechanical connection element 406 may be adapted for supporting the pendant 400. The pendant 400 further comprises a reflector or screen 403, which in the embodiment shown may be identical with or formed by the reflective collimator 51.

[0203] The pendant 400 may further comprise a driver 402 configured for controlling the plurality of LED filament arrangements 1, 100, 101, 102, 103, 104. The driver 402 may or may not be the same unit as the controller 13 of each LED filament arrangement 1, 100, 101, 102, 103, 104 of the plurality of LED filament arrangements.

[0204] The pendant 400 further comprises an electrical wiring 404 for connection to a source of electricity, such as a mains. The pendant 400 may further comprise mechanical wiring 405. The mechanical wiring 405 may be adapted for supporting the pendant 400. The pendant 400 may further comprise a mechanical connection element 406 configured to connect the mechanical wiring 405 and the plurality of LED filament arrangements 1, 100, 101, 102, 103, 104.

[0205] Turning now to Fig. 20, an exemplary luminaire in the form of a troffer panel 410 is shown. The troffer panel 410 comprises a plurality of LED filament arrangements 1, 100, 101, 102, 103, 104 according to any embodiment of the invention. In the embodiment shown, the troffer panel 410 comprises nine LED filament arrangements 1 of the type described in relation to Figs. 1 and 2. The plurality of LED filament arrangements 1, 100, 101, 102, 103, 104 may be assembled by means of snap-locking or click-locking or frictionlocking mechanisms.

[0206] Turning finally to Fig. 21, an exemplary luminaire in the form of a panel or tile 420 is shown. The panel or tile 420 comprises a plurality of LED filament arrangements 1, 100, 101, 102, 103, 104 according to any embodiment of the invention used as side-lit lighting elements for coupling light into a (thin) light guide 408. In the embodiment shown, the panel or tile 420 comprises two LED filament arrangements 1 of the type described in relation to Figs. 1 and 2.

[0207] The light guide 408 comprises a reflective top side 409 and bottom light-outcoupling surface 407. Such a configuration allows for making a very thin and efficient2025PF80051

[0208] 22

[0209] light panel or tile 420 capable of providing a very uniform and comfortable low-brightness light emission from the bottom light-outcoupling surface 407. The light guide 408 may be made of a solid material. Alternatively, the light guide 408 may be a structure with an empty core and with reflective walls and top side 409. A light diffusing or scattering window 411 may be arranged at the bottom light-outcoupling surface 407. In case the light guide part 408 and the LED filament arrangements 1 are both made out of a solid material, it may be advantageous to ensure good optical contact between the light guide part 408 and the LED filament arrangements 1, or to make both the light guide part 408 and the LED filament arrangements 1 out of one solid light transparent body.

[0210] It is noted that the luminaires 400, 410 and 420 shown in Figs. 19-21 are only examples of a luminaire according to the invention. Any suitable type of luminaire, particularly luminaire for directional lighting, may be envisaged, such as but not limited to, a standing luminaire, a wall hung luminaire, a chandelier, a reading luminaire, an outdoor luminaire, and a table luminaire.

[0211] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0212] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Claims

2025PF8005123CLAIMS:

1. A LED filament arrangement (1) configured to, in operation, emit LED filament arrangement light (2) and comprising at least one LED filament (31), the at least one LED filament being configured to, in operation, emit LED filament light (41), wherein the at least one LED filament (31) is arranged in a collimator (51), wherein the collimator (i) is reflective and elongated, (ii) comprises a light exit window (61), and (iii) is configured to redirect the LED filament light (41) in a direction towards the light exit window, whereinthe LED filament arrangement (1) further comprises a plurality of reflecting lamellae (71) arranged in the collimator (51), whereinthe plurality of reflecting lamellae (71) is arranged extending perpendicular to the at least one LED filament (31), andwherein at least one of the following applies:(i) each lamella of the plurality of reflecting lamellae (71) comprises two parts (74, 75) and the at least one LED filament (31) is arranged between the two parts (74, 75), and / or at least one of the two parts (74, 75) comprises a recess (76) configured to enable arranging the at least one LED filament (31) at least partly recessed in the recess, and (ii) each lamella of the plurality of reflecting lamellae (71) comprises a through hole (73) being entirely enclosed by the respective lamella, wherein the at least one LED filament (31) is arranged in the through holes (73).

2. The LED filament arrangement (1) according to claim 1, and comprising a plurality of LED filaments (31, 32), each LED filament of the plurality of LED filaments being configured to, in operation, emit respective LED filament light (41, 42), wherein each LED filament of the plurality of LED filaments (31, 32) is arranged in a respective associated collimator (51, 52), whereineach collimator (i) is reflective and elongated, (ii) comprises a respective associated light exit window (61, 62), and (iii) is configured to redirect the LED filament light (41, 42) in a direction towards the light exit window, wherein2025PF8005124each collimator (51, 52) further comprises a plurality of respective associated reflecting lamellae (71, 72), each plurality of reflecting lamellae (71, 72) being arranged extending perpendicular to the LED filament (31, 32) arranged in the collimator, and wherein at least one of the following applies:(i) each lamella of each plurality of respective associated reflecting lamellae (71, 72), comprises two parts (74, 75), and each LED filament of the plurality of LED filaments (31, 32) is arranged between the two parts (74, 75) of the plurality of respective associated reflecting lamellae (71, 72), and / or at least one of the two parts (74, 75) comprises a recess (76) configured to enable arranging a LED filament of the plurality of LED filaments (31, 32) at least partly recessed in the recess, and(ii) each plurality of respective associated reflecting lamellae (71, 72), comprises through holes (73), wherein a LED filament of the plurality of LED filaments (31, 32), is arranged in the through holes (73).

3. The LED filament arrangement according to any one of the above claims, wherein at least one of the collimator (51) and the plurality of reflecting lamellae (71), or at least one of each collimator (51, 52) and each plurality of reflecting lamellae (71, 72), is / are specularly reflecting.

4. The LED filament arrangement according to any one of the above claims, wherein the at least one LED filament (31) is arranged in an optical center of the collimator (51), or each LED filament of the plurality of LED filaments (31, 32) is arranged in an optical center of the respective associated collimator (51, 52).

5. The LED filament arrangement according to any one of the above claims, wherein the at least one LED filament (31), or each LED filament of the plurality of LED filaments (31, 32), comprises a substrate (36) with a first major surface (361), and a second major surface (362) opposite to the first major surface, and wherein one of the following applies:the at least one LED filament (31), or at least one LED filament of the plurality of LED filaments (31, 32), comprises an array of LED light sources (33) arranged on the first major surface (361), and wherein the at least one LED filament (31), or the at least one LED filament of the plurality of LED filaments (31, 32), is arranged in the2025PF8005125collimator in such a way that the array of LED light sources (33) face a bottom part (53) of the collimator, andthe at least one LED filament (31), or at least one LED filament of the plurality of LED filaments (31, 32), comprises a first array of LED light sources (33) arranged on the first major surface (361) and a second array of LED light sources (34) arranged on the second major surface (362), and wherein the at least one LED filament (31), or the at least one LED filament of the plurality of LED filaments (31, 32), is arranged in the collimator in such a way that the first array of LED light sources (33) and the second array of LED light sources (34) face mutually opposite side parts (54, 55) of the collimator.

6. The LED filament arrangement according to any one of the above claims, wherein the plurality of reflecting lamellae (71) and the at least one LED filament (31) are mechanically attached to one another and thermally connected to one another, or each plurality of reflecting lamellae (71, 72) is mechanically attached and thermally connected to the LED filament (31, 32) arranged in the same collimator.

7. The LED filament arrangement according to any one of the above claims, whereinthe at least one LED filament (31) and the collimator (51) are mechanically attached to one another and thermally connected to one another, or each LED filament (31, 32) of the plurality of LED filaments is mechanically attached and thermally connected to the collimator (51, 52) in which it is arranged.

8. The LED filament arrangement according to any one of the above claims, wherein a spacing (9) is provided between the at least one LED filament (31) and at least one lamella of the plurality of reflecting lamellae (71), or between at least one LED filament of the plurality of LED filaments (31, 32) and at least one lamella of the plurality of reflecting lamellae (71, 72) arranged in the same collimator, wherein the spacing (9) is at most 1 mm.

9. The LED filament arrangement according to any one of the above claims, wherein at least one of the following applies:a surface (77) of at least one lamella of the plurality of reflecting lamellae (71) adjacent to the at least one LED filament (31) is shaped such that at least a part of the lamella is provided with the shape of a wedge tapering away from the at least one LED filament (31), and2025PF8005126a surface (77) of at least one lamella of each plurality of reflecting lamellae (71, 72) adjacent to the respective LED filament of the plurality of LED filaments (31, 32) is shaped such that at least a part of the lamella is provided with the shape of a wedge tapering away from the respective LED filament of the plurality of LED filaments (31, 32).

10. The LED filament arrangement according to any one of the above claims, wherein one or more of the following apply:the at least one LED filament (31) is free from LED light sources (33, 34) at a position directly adjacent to the plurality of lamellae (71),at least one LED filament of the plurality of LED filaments (31, 32) is free from LED light sources (33, 34) at a position directly adjacent to the plurality of lamellae (71, 72) arranged in the same collimator,the at least one LED filament (31) is free from LED light sources (33, 34) in segments (35), which in an assembled condition of the LED filament arrangement are arranged directly adjacent to the plurality of lamellae (71), andat least one LED filament of the plurality of LED filaments (31, 32) is free from LED light sources (33, 34) in segments (35), which in an assembled condition of the LED filament arrangement are arranged directly adjacent to the plurality of lamellae (71, 72) arranged in the same collimator,11. The LED filament arrangement according to any one of the above claims, wherein one or more of the following apply:at least one lamella of the plurality of reflecting lamellae (71) comprises a base (78) configured to be positioned directly adjacent to the at least one LED filament (31), wherein the base (78) is transparent, andat least one lamella of each plurality of reflecting lamellae (71, 72) comprises a base (78) configured to be positioned directly adjacent to the LED filament of the plurality of LED filaments (31, 32) arranged in the same collimator, wherein the base (78) is transparent.

12. A LED filament arrangement according to any one of the above claims, wherein at least one of the following applies:2025PF8005127the collimator (51) comprises a first collimator part (11) and a second collimator part (12), wherein the first collimator part and the second collimator part comprise mutually different shapes,each collimator (51, 52) comprises a first collimator part (11) and a second collimator part (12), wherein the first collimator part and the second collimator part comprise mutually different shapes,the collimator (51), or the second collimator part (12) of the collimator (51), is a parabolic reflector, or a reflector shaped as a small letter omega, co, or a m-shaped reflector, and, where provided,each collimator (52), or the second collimator part (12) of each collimator (51, 52), is a parabolic reflector, or a reflector shaped as a small letter omega, co, or a m-shaped reflector.

13. A LED filament arrangement according to any one of the above claims, further comprising a controller (13) configured to control the at least one LED filament (31), or to individually control each LED filament of the plurality of LED filaments (31, 32).

14. A LED filament arrangement according to any one of the above claims, wherein one or more of the following apply:the at least one LED filament (31) comprises a substrate (36), or at least one LED filament of the plurality of LED filaments (31, 32) comprises a substrate (36), wherein the substrate comprises one or more of the following:mutually opposite end sections (363, 364) being free from LED light sources (33, 34) and configured to, in an assembled condition of the LED filament arrangement, extend into or be attached to the collimator (51), or a collimator (51, 52),local or continuous extensions (365, 366) configured to, in an assembled condition of the LED filament arrangement, extend towards a lamella of the plurality of lamellae (71) or a lamella of a plurality of lamellae (71, 72),a local or continuous extension (367) configured to, in an assembled condition of the LED filament arrangement, extend towards the collimator (51) or a collimator (51, 52), anda first major surface (361) and a second major surface (362) opposite to the first major surface, and a luminescent encapsulant (14, 15) arranged on one or both major surfaces (361, 362) of the substrate, the substrate (36) being a light-transmissive substrate.2025PF800512815. A luminaire comprising at least one LED filament (1) arrangement according to any one of the above claims.

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