LED filament luminaire with enclosure

Abstract

A light-emitting diode, LED, filament luminaire (100) configured to provide, in operation, LED filament luminaire light, is provided. The LED filament luminaire comprises a plurality of LED filaments (110), first (170) and second (180) electrodes arranged at respective ends of the LED filament, and an enclosure extending along a principal axis, A. The enclosure comprises a reflective base portion (210), a reflective side wall (220), a light exit window (230), and a plurality of electrical contacts (240). Each LED filament is connected to a respective pair of electrical contacts, wherein the enclosure encloses the plurality of LED filaments and defines a mixing chamber (300) for the LED filament light, wherein the elongated encapsulant of each LED filament is arranged at least at a first minimum distance, D1, from the base portion and at least at a second minimum distance, D2, from the side wall.

Description

[0001] LED FILAMENT LUMINAIRE WITH ENCLOSURE

[0002] FIELD OF THE INVENTION

[0003] The present invention generally relates to a light emitting diode, LED, filament luminaire. More specifically, the present invention relates to a LED filament luminaire comprising an enclosure defining a mixing chamber for LED filament luminaire light.

[0004] BACKGROUND OF THE INVENTION

[0005] The use of light emitting diodes, LEDs, for illumination purposes continues to attract attention. Compared to incandescent lamps, fluorescent lamps, neon tube lamps, etc., LEDs provide numerous advantages such as a longer operational life, a reduced power consumption, and an increased efficiency related to the ratio between light energy and heat energy.

[0006] Many LED filament lamps or devices in the prior art comprise LED filaments for achieving the above-mentioned advantages, as well as achieving aesthetically appealing lamps. However, it should be noted that LED filaments, at least until now, are very rarely applied in luminaires, although it will be appreciated that LED filaments may improve several aspects and / or properties of luminaires.

[0007] Hence, it is an object of the present invention to propose a luminaire comprising LED filaments, whereby the luminaire provides a high efficiency, a reliable and cost-effective mechanical -electrical solution, whilst providing a desired aesthetical appearance and / or decorative aspect of the LED filaments and / or the luminaire.

[0008] SUMMARY OF THE INVENTION

[0009] It is of interest to explore the possibility of providing a luminaire by combining one or more of the numerous advantages of LED filaments comprising LEDs, whilst improving the light emission efficiency and improving the appearance and / or the decorative aspect of the LED filaments and / or luminaire comprising LED filaments. This and other objects are achieved by providing a LED filament luminaire having the features in the independent claim. Preferred embodiments are defined in the dependent claims.

[0010] According to the present invention, there is provided a LED filament luminaire configured to provide, in operation, LED filament luminaire light. The LED filament luminaire comprises a plurality of LED filaments configured to emit LED filament light. Each LED filament of the plurality of LED filaments comprises an elongated carrier comprising a first major surface, and an array of a plurality of LEDs arranged on the first major surface. Each LED filament further comprises an elongated encapsulant covering the plurality of LEDs and at least partly the first major surface, a first electrode arranged at a first LED filament end of the LED filament and a second electrode arranged at a second LED filament end of the LED filament, opposite to the first LED filament end, for electrical connection of the LED filament. The LED filament luminaire further comprises an enclosure extending along a principal axis, A, comprising a base portion having a reflective inner base surface, a side wall circumferential of the base portion and having a reflective inner side wall surface, and a light exit window, oppositely arranged the base portion. The LED filament luminaire further comprises a plurality of electrical contacts provided on an inner side of the side wall of the enclosure, wherein each LED filament of the plurality of LED filaments is connected to a respective pair of electrical contacts, comprising an anode and a cathode, of the plurality of electrical contacts via the first electrode and the second electrode. The enclosure encloses the plurality of LED filaments and defines a mixing chamber arranged to at least partially mix the LED filament light before exiting the LED filament luminaire through the light exit window as the LED filament luminaire light, wherein at least a major portion of the elongated encapsulant of each LED filament of the plurality of LED filaments is arranged at least at a first minimum distance, DI, from the base portion and at least at a second minimum distance, D2, from the side wall.

[0011] Thus, the present invention is based on the idea of providing a LED filament luminaire, whereby LED filaments are arranged within an enclosure of the luminaire for a mixing of the LED filament light. By the arrangement of the LED filaments within the enclosure, the properties of the light emission from the luminaire are improved, whilst providing a desired aesthetical appearance and / or decorative aspect of the LED filaments and / or the LED filament luminaire.

[0012] The present invention is particularly advantageous by the arrangement of the

[0013] LED filaments in the enclosure at minimum distances from the base portion and side wall, achieving an effect of seemingly “floating” LED filaments. By this effect, the LED filament luminaire achieves a particularly attractive appearance.

[0014] The present invention is further advantageous by its achievement of lighting efficiency and aesthetical appearance. Albeit prior art arrangements may use LED filaments in lamps or devices for trying to improve the efficiency, the use of LED filaments in luminaires is rarely encountered, and does not, in any case, achieve the properties nor the effects due to the features of the luminaire as described for an improved appearance whilst taking into account efficiency and light distribution.

[0015] The present invention is further advantageous by its versatility concerning the choice of the arrangement of the plurality of LED filaments, whereby enhanced lighting properties and / or enhanced attractive aspects may be obtained accordingly.

[0016] The present invention is further advantageous by the combination of the reflective enclosure and the LED filaments, achieving a particular lighting effect of the LED filament luminaire in terms of lighting distribution and attractiveness.

[0017] The present invention is further advantageous in that the numerous advantages of using LED technology may be combined with the attractiveness and the appealing properties of the LED filament luminaire as disclosed.

[0018] The present invention is further advantageous in that the LED filament luminaire of the present invention comprises relatively few components. The low number of components is advantageous in that the LED filament luminaire is relatively inexpensive to fabricate. Moreover, the low number of components of the LED filament luminaire implies an easier recycling, especially compared to devices or arrangements comprising a relatively high number of components which impede an easy disassembling and / or recycling operation.

[0019] There is provided a LED filament luminaire configured to provide, in operation, LED filament luminaire light. The LED filament luminaire comprises a plurality of LED filaments configured to emit LED filament light. It will be appreciated that a LED filament is providing LED filament light and comprises a plurality of LEDs arranged in a linear array. The LED filament has a length, L, a width, W, and a thickness, T, wherein L > 5W, preferably L > 10W and L > 10T. The width, W, and the thickness, T, may typically be in a range from 1 to 5 mm. The length, L, may be in a range from 3 to 10 cm. The LED filament may be arranged in a straight configuration or in a non-straight configuration such as for example a curved configuration, a 2D / 3D spiral or a helix. Each LED filament of the plurality of LED filaments comprises an elongated carrier comprising a first major surface, and an array of a plurality of LEDs arranged on the first major surface. The elongated carrier may, for instance, be a substrate, that may be rigid (made from e.g. a polymer, glass, quartz, metal or sapphire) or flexible (e.g. made of a polymer or metal e.g. a film or foil). The elongated carrier may be reflective or light transmissive, such as translucent and preferably transparent. By the term “array”, it is here meant a linear arrangement or chain of LEDs, or the like. Each LED filament further comprises an elongated encapsulant covering the plurality of LEDs and at least partly the first major surface. By the term “encapsulant”, it is here meant an elongated material, element, arrangement, or the like, which in the present context is configured or arranged to at least partially surround, encapsulate and / or enclose the carrier and the array(s) of the plurality of LEDs. The encapsulant may be a polymer material which may be flexible such as for example a silicone. The encapsulant may comprise a luminescent material that is configured to at least partly convert LED light into converted light. The luminescent material may be a phosphor such as an inorganic phosphor and / or quantum dots or rods. The encapsulant may furthermore comprise a light scattering material configured to at least partly scatter LED light into scattered light. Each LED filament further comprises a first electrode arranged at a first LED filament end of the LED filament and a second electrode arranged at a second LED filament end of the LED filament, opposite to the first LED filament end, for electrical connection of the LED filament. The LED filament luminaire further comprises an enclosure extending along a principal axis, A, comprising a base portion having a reflective inner base surface, a side wall circumferential of the base portion and having a reflective inner side wall surface, and a light exit window, oppositely arranged the base portion. Hence, the enclosure, e.g. in the form of a housing or cover, comprises a reflective base and side wall, and the light is arranged to exit the enclosure via the light exit window. By the term “reflective”, it is here meant a reflectivity which is at least 80%, preferably at least 85%, more preferred at least 88%, and most preferred at least 90%. The LED filament luminaire further comprises a plurality of electrical contacts provided on an inner side of the side wall of the enclosure, wherein each LED filament of the plurality of LED filaments is connected to a respective pair of electrical contacts, comprising an anode and a cathode, of the plurality of electrical contacts via the first electrode and the second electrode. Hence, each LED filament is connected to the side wall of the enclosure, whereby the first electrode thereof is connected to the anode (cathode) and the second electrode thereof is connected to the cathode (anode). The enclosure encloses the plurality of LED filaments and defines a mixing chamber arranged to at least partially mix the LED filament light before exiting the LED filament luminaire through the light exit window as the LED filament luminaire light. By “mixing chamber”, it is here meant that the reflectivity properties of the enclosure provide the possibility for the LED filament light to reflect and to mix before exiting the LED filament luminaire via the light exit window. At least a major portion of the elongated encapsulant of each LED filament of the plurality of LED filaments is arranged at least at a first minimum distance, DI, from the base portion and at least at a second minimum distance, D2, from the side wall. Hence, each LED filament is arranged or mounted in the enclosure in such a way that the elongated encapsulant is arranged at least at a first minimum distance, DI, from the base portion and at least at a second minimum distance, D2, from the side wall.

[0020] According to an embodiment of the present invention, the reflective inner base surface and the reflective inner side wall surface may mutually differ in at least one of diffusivity and reflectivity. Hence, the reflective inner base surface may have a (first) diffusivity and a (first) reflectivity, and the reflective inner side wall may have a (second) diffusivity and a (second) reflectivity, wherein the first and second diffusivities differ and / or the first and second reflectivities differ. The present embodiment is advantageous in that the properties of light distribution and / or aesthetic appearance of the LED filaments and / or LED filament luminaire may be customized to an even higher extent.

[0021] According to an embodiment of the present invention, a third distance, D3, between the anode and the cathode along the side wall, and a fourth distance, D4, between a first electrode end, El, of the first electrode and a second electrode end, E2, of the second electrode, may fulfil D3 > D4. The present embodiment is advantageous in that the LED filaments of the luminaire may be arranged in an even more advantageous and / or convenient manner, still fulfilling the requirement of minimum distances between the encapsulant of each LED filament and the base portion and side wall, respectively.

[0022] According to an example of the present invention, the fourth distance, D4, and a diameter, Da, of the enclosure, may fulfil Da > D4. For example, 3-Da > Da > LLD4, or even more preferred 1.5 -Da > Da > 1.1 -Da in case of a rectangular (e.g. square) enclosure.

[0023] According to an embodiment of the present invention, the LED filament luminaire may further comprise a flexible strip arranged on the inner side of the side wall of the enclosure, wherein the flexible strip comprises the plurality of electrical contacts. The present embodiment is advantageous in that the flexible strip provides a particularly convenient provision of the electrical contacts for electrical connection to the LED filaments.

[0024] According to an embodiment of the present invention, the flexible strip may comprise electrically conductive tracks electrically connected to one or more electrical contacts of the plurality of electrical contacts. The present embodiment is advantageous in that the flexible strip, comprising the electrically conductive tracks and the plurality of electrical contacts, provides a convenient and reliable mechanical-electrical support for the LED filaments, thereby even further augmenting the electrical and / or mechanical reliability and robustness of the LED filament luminaire.

[0025] According to an embodiment of the present invention, the LED filament luminaire may comprise a central cylindrical space, C, extending from the base to the light exit window, around the principal axis, A, with a radius, R, perpendicular to the principal axis, A, wherein the LED filaments are arranged peripheral of the central cylindrical space, C, and wherein a volume of the central cylindrical space, Vc, and a volume of the enclosure, VE, fulfil Vc > 0.25-VE. Hence, the central cylindrical space, C, defines a (central) volume of the LED filament luminaire, whereby all LED filaments are arranged or provided outside (peripheral) of the central cylindrical space, C. In other words, the central cylindrical space, C, defines a (central) volume of the LED filament luminaire in which no LED filament is arranged or provided. By the peripherally arranged LED filaments, the present embodiment is particularly advantageous concerning the light distribution properties and / or the attractiveness of the LED filaments and / or the LED filament luminaire.

[0026] According to an embodiment of the present invention, the plurality of LED filaments, in a projection parallel to the principal axis, A, may be arranged to form a polygon shape. Hence, seen along (parallel to) the principal axis, A, of the luminaire, the plurality of LED filaments may have the shape or form of a polygon, such as e.g. a triangle, a square, a rectangle, a pentagon, etc. The present embodiment is advantageous in that the LED filaments achieve an attractive shape, leading to an even further attractive LED filament luminaire.

[0027] According to an embodiment of the present invention, the LED filament luminaire may be cylinder-shaped. The present embodiment is advantageous in that this shape of the luminaire and / or enclosure may enhance the mixing properties of the luminaire, which in turn may augment the light distribution and / or attractiveness of the emitted LED filament light.

[0028] According to an embodiment of the present invention, a cross-section of the LED filament luminaire, perpendicular to the principal axis, A, may have a polygon shape. Furthermore, at least one of any LED filament of the plurality of LED filaments may be connected between a first side wall portion and a second side wall portion, wherein the first side wall portion and the second side wall portion are not oppositely arranged in a direction, B, perpendicular to the principal axis, A, and any LED filament of the plurality of LED filaments is connected between two adjacent side wall portions in a circumferential direction, F, perpendicular to the principal axis, A, may be fulfilled. Hence, seen along (parallel to) the principal axis, A, of the LED filament luminaire, the luminaire may have a polygon shape, e.g. a triangle, square, rectangle, pentagon, etc. Furthermore, one or more LED filaments may be connected between (two) side wall portions which are not oppositely arranged in a direction, B, perpendicular to the principal axis, A, and / or one or more LED filaments may be connected between two adjacent side wall portions in a circumferential direction, F, perpendicular to the principal axis, A. The present embodiment is advantageous in that the arrangement of LED filaments in the enclosure achieves a particularly advantageous light distribution and / or attractiveness of the LED filaments and / or the LED filament luminaire.

[0029] According to an example of the present invention, any (first) LED filament of the plurality of LED filaments may have a length which is different from a length of any (second) LED filament of the plurality of LED filaments. For example, all LED filaments may have different lengths. According to an example, a relation between a shortest length, Lmin, of a LED filament, and a longest length, Lmax, of a LED filament, of the plurality of LED filaments, 2-Lmin > Lmax 1.6’ min. According to yet another example, in case of an elliptical (e.g. circular) enclosure of diameter Dc, the relation 0.8-D3 > Lmin may be fulfilled.

[0030] According to an embodiment of the present invention, at least two LED filaments of the plurality of LED filaments may be arranged perpendicular to the principal axis, A. The present embodiment is advantageous in that symmetry of the LED filaments may be achieved, which may augment the light distribution and / or the aesthetic attractiveness of the LED filament luminaire.

[0031] According to an embodiment of the present invention, at least two LED filaments of the plurality of LED filaments may be obliquely arranged with respect to a direction, B, perpendicular to the principal axis, A. Hence, the LED filaments arranged on (along) the side wall may be inclined with respect to the direction, B.

[0032] According to an embodiment of the present invention, the at least two LED filaments of the plurality of LED filaments may intersect in a projection parallel to the principal axis, A. Hence, seen along (parallel to) the principal axis, A, of the luminaire, two or more LED filaments may intersect (cross). The embodiment may, for example, be achieved by double electrical contacts (pads). The present embodiment is advantageous in that particularly beautiful and attractive patterns of LED filaments may be provided, which consequently contributes to the LED filament luminaire attractiveness. According to an embodiment of the present invention, the first electrode, a LED filament portion between the first and second electrodes, and the second electrode, may together form a U-shape. Hence, the LED filament may be arranged “offset” from a position it would have otherwise. The present embodiment is advantageous by the achieved versatility of the LED filament luminaire.

[0033] According to an embodiment of the present invention, at least one of DI > 5 mm and D2 > 5 mm, and wherein the enclosure has a height, He, parallel to the principal axis, A, and a width, Ee, perpendicular to He, wherein 0.9-He > DI > 0.1-He and 0.4-Ee > D2 > 0.05-Ee, is fulfilled. Hence, both DI and D2 may be at least 5 mm, and / or the enclosure may have dimensions such that its height, He, parallel to the principal axis, A, and its width, Ee, perpendicular to He, fulfil 0.9-He > DI > 0.1-He and 0.4-Ee > D2 > 0.05-Ee.

[0034] According to an embodiment of the present invention, the LED filament luminaire may further comprise a controller configured to individually control the LED filaments of the plurality of LED filaments. By “controller”, it is here meant any device, unit, or the like, which is able to control the luminous flux either by wire or via wireless technology. The present embodiment is advantageous in that the LED filaments may be conveniently controlled (either automatically or manually (by an operator or user)), such that a desired light distribution and / or aesthetic effect may be achieved. According to an example, the controller may be configured to control the LED filaments such that at least two LED filaments of the plurality of LED filaments emit light having different correlated color temperatures, CCTs, whereby the correlated color temperature, CCT, of the LED filament luminaire light is varied. The present example is advantageous by the possibility of the controller to vary the correlated color temperature, CCT, of the LED filament light for even further enhancing the light distribution and / or the aesthetic appearance of the LED filaments. For example, the LED filament luminaire, via the difference in color temperature between its LED filaments, may provide a desired color temperature of the LED filament light. The present example is further advantageous in that this difference in color temperature may even further contribute to the aesthetical attractiveness of the LED filament luminaire during operation.

[0035] In embodiments, the plurality of LED filaments may be configured to emit white LED filament light. The white LED filament light may have a correlated color temperature, CCT, in a range from 1700K to 6500K and / or have a color rendering index, CRI, of at least 80 (or at least 85). The plurality of LED filaments may emit white light having a different correlated color temperature, e.g. a difference of at least 500K may be used.

[0036] In embodiments, the elongated encapsulant may cover at least partly a second major surface, opposite to the first major surface, of the elongated carrier.

[0037] Further objectives of, features of, and advantages with, the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims. Those skilled in the art will realize that different features of the present invention can be combined to create embodiments other than those described in the following.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS

[0039] 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.

[0040] Fig. 1 schematically shows a LED filament lamp according to the prior art, Fig. 2 schematically shows a LED filament luminaire according to an exemplifying embodiment of the present invention,

[0041] Figs. 3-5 schematically show views of LED filament luminaires according to exemplifying embodiments of the present invention,

[0042] Fig. 6 schematically shows an arrangement of LED filaments of a LED filament luminaire according to an exemplifying embodiment of the present invention, and Fig. 7 schematically shows an installation of a LED filament luminaire according to an exemplifying embodiment of the present invention.

[0043] DETAILED DESCRIPTION

[0044] Fig. 1 shows a LED filament lamp 10 according to the prior art, comprising a plurality of LED filaments 20. LED filament lamps 10 of this kind are highly appreciated as they are very decorative, as well as providing numerous advantages compared to incandescent lamps such as a longer operational life, a reduced power consumption, and an increased efficiency related to the ratio between light energy and heat energy. However, it should be noted that LED filaments, at least until now, are very rarely applied in luminaires, although it will be appreciated that LED filaments may improve several aspects and / or properties of luminaires. Hence, it is of interest to explore the provision of LED filaments in luminaires, and to provide a desired light distribution and / or decorative aspect of LED filaments and / or a LED filament luminaire. Fig. 2 shows a LED filament arrangement 100 according to an exemplifying embodiment of the present invention. The LED filament luminaire 100 is configured to provide, in operation, LED filament luminaire light 105. The LED filament luminaire 100 comprises a plurality of LED filaments 110 configured to emit LED filament light 115. One or more or all LED filaments 110 may emit white LED filament light. The white LED filament light may have a correlated color temperature, CCT, in a range from 1700K to 6500K and / or have a color rendering index, CRI, of at least 80. In Fig. 2, the LED filament luminaire 100, as an example, comprises four LED filaments 110, but it should be noted that the number of LED filaments 110 is arbitrary. For example, the plurality of LED filaments 110 may comprise at least 4 LED filaments 110, preferably at least 5 LED filaments 110, more preferably at least 6 LED filaments 110, and most preferably at least 7 LED filaments 110. Each LED filament 110 of the plurality of LED filaments 110 comprises an elongated carrier 120 comprising a first major surface 140, and an array of a plurality of LEDs 150 arranged on the first major surface 140. It should be noted that the LED filament 110 may comprise substantially any number of array(s) of a plurality of LEDs 150. The plurality of LEDs 150 preferably comprises more than 5 LEDs, more preferably more than 8 LEDs, and even more preferred more than 10 LEDs. The plurality of LEDs 150 may be direct emitting LEDs which provide a color. Each LED filament 110 further comprises an elongated encapsulant 160 covering the plurality of LEDs 150 and at least partly the first major surface 140. The encapsulant 160 may comprise at a light-scattering material configured to scatter at least part of the LED light into scattered light and / or a luminescent material configured to convert at least part of the LED light into converted light. The luminescent material of the encapsulant 160 may be a light-scattering material, e.g. a polymer matrix comprising BaSCU, AI2O3 and / or TiCE particles. The luminescent material may be a phosphor such as an inorganic phosphor (e.g. YAG, LuAG, ECAS, KSiF, etc.) and / or quantum dots or rods. The phosphor may further be e.g. a (blue) green / yellow and / or red phosphor. Although not shown, the thickness of the encapsulant 160 and / or a concentration of the luminescent material in the encapsulant 160 may vary over the length of the LED filament 110.

[0045] Each LED filament 110 further comprises a first electrode 170 arranged at a first LED filament end of the LED filament 110 and a second electrode 180 arranged at a second LED filament end of the LED filament 110, opposite to the first LED filament end, for electrical connection of the LED filament 110. The LED filament luminaire 100 further comprises an enclosure 200 extending along a principal axis, A. The enclosure 200 in Fig. 2 is exemplified as having a cylinder shape, but it will be appreciated that the enclosure 200 may have substantially any form or shape. The enclosure 200 comprises a base portion 210 having a reflective inner base surface 215. The enclosure 200 further comprises a side wall 220 circumferential of the base portion 210 and having a reflective inner side wall surface 225. The side wall 200 hereby extends perpendicular from the base portion 210. The reflective inner base surface 215 and the reflective inner side wall surface 225 may mutually differ in diffusivity and / or reflectivity. Hence, the reflective inner base surface 215 may have a (first) diffusivity and a (first) reflectivity, and the reflective inner side wall 225 may have a (second) diffusivity and a (second) reflectivity, wherein the first and second diffusivities differ and / or the first and second reflectivities differ. The enclosure 200 further comprises a light exit window, oppositely arranged the base portion 210, whereby the light exit window is not present in Fig. 2 for a view of the components and features of the LED filament lamp 100. The light exit window may be at least partially light transmissive (e.g. transparent), and may furthermore be configured to diffuse the LED filament light 115.

[0046] The LED filament luminaire 100 further comprises a plurality of electrical contacts 240 provided on an inner side of the side wall 225 of the enclosure 200, wherein each LED filament 110 of the plurality of LED filaments 110 is connected to a respective pair of electrical contacts 240, comprising an anode 300 and a cathode 310, of the plurality of electrical contacts 240 via the first electrode 170 and the second electrode 180. The LED filament luminaire 100 may comprise a flexible strip 500 arranged on the inner side of the side wall 225 of the enclosure 200, wherein the flexible strip 500 comprises the plurality of electrical contacts 240. The flexible strip 500 may comprise electrically conductive tracks 600 electrically connected to one or more electrical contacts 240 of the plurality of electrical contacts 240.

[0047] The enclosure 200 encloses the plurality of LED filaments 110 and defines a mixing chamber 400 arranged to at least partially mix the LED filament light 115 before exiting the LED filament luminaire 100 through the light exit window as the LED filament luminaire light 105. At least a major portion of the elongated encapsulant 160 of each LED filament 110 of the plurality of LED filaments 110 is arranged at least at a first minimum distance, DI, from the base portion 210 of the enclosure 200. Furthermore, at least a major portion of the elongated encapsulant 160 of each LED filament 110 of the plurality of LED filaments 110 is arranged at least at a second minimum distance, D2, from the side wall 220 of the enclosure 200. The first minimum distance, DI, may for example be larger than 5 mm, i.e. DI > 5 mm, and the second minimum distance, D2, may for example be larger than 5 mm, i.e. D2 > 5 mm. Furthermore, the enclosure 200 has a height, He, parallel to the principal axis, A, and a width, Ee, (in this example, diameter) perpendicular to He, wherein 0.9-He > DI > 0.1-He and / or 0.4-Ee > D2 > 0.05-Ee, may be fulfilled. The LED filament luminaire 100 may further define a third distance, D3, between the anode 300 and the cathode 310 along the side wall 220 of the enclosure 200, and a fourth distance, D4, between a first electrode end, El, of the first electrode 170 and a second electrode end, E2, of the second electrode 180, whereby D3 is larger than D4, i.e. D3 > D4 is fulfilled. For example, the third distance, D3, may be 3.5 cm to 14 cm, and the fourth distance, D4, may be 3 cm to 10 cm, whilst D3 > D4 is fulfilled.

[0048] The LED filament luminaire 100 may furthermore comprise an electrical connection (not shown) connected to the plurality of electrical contacts 240 for a supply of power to the plurality of LED filaments 110 of the LED filament luminaire 100.

[0049] Fig. 3 schematically shows LED filament luminaires according to exemplifying embodiments of the present invention. As Fig. 3 shows schematic configurations of the LED filament luminaire of Fig. 2 as an overview and with many references omitted, it is also referred to Fig. 2 and the associated text for an increased understanding of the LED filament luminaire 100. Fig. 3 shows three exemplifying embodiments of the LED filament luminaire 100 in a projection parallel to the principal axis, A, i.e. seen along (parallel to) the principal axis, A, of the LED filament luminaire 100. Within the cylinder-shaped enclosure 200 of the LED filament luminaire 100, the plurality of LED filaments 110 are arranged to form a polygon shape. In the leftmost figure of Fig. 3, the three LED filaments 110 have the shape of a triangle. In the middle figure of Fig. 3, the four LED filaments 110 have the shape of a square, thereby corresponding to the LED filament luminaire as exemplified in Fig. 2. In the rightmost figure of Fig. 3, the five LED filaments 110 have the shape of a pentagon. It will be appreciated that the plurality of LED filaments 110 of the LED filament luminaire 100 may take on further polygon shapes, and that Fig. 3 merely presents some examples of the LED filament luminaire 100.

[0050] Fig. 4 schematically shows a LED filament luminaire 100 according to an exemplifying embodiment of the present invention. Fig. 4 shows a configuration of the LED filament luminaire 100 of Fig. 2 as an overview and with many references omitted, and it is hereby also referred to Fig. 2 and the associated text for an increased understanding of the LED filament luminaire 100. The LED filament luminaire 100 in Fig. 4 is shown in a projection parallel to the principal axis, A, i.e. seen along (parallel to) the principal axis, A. According to this example, 8 LED filaments 110 are arranged within the cylinder-shaped enclosure 200 of the of LED filament luminaire 100. Here, the plurality of LED filaments 110 form a multiple star pattern, but it should be noted that substantially any kind of pattern may be created with substantially any kind of number of LED filaments 110. Here, the LED filament luminaire 100 comprises a central cylindrical space, C, which extends from the base to the light exit window of the LED filament luminaire 100. The central cylindrical space, C, extends around the principal axis, A, with a radius, R, perpendicular to the principal axis, A. The plurality of LED filaments 110 are arranged peripheral of the central cylindrical space, C. Hence, the central cylindrical space, C, defines a (central) volume of the LED filament luminaire 100, whereby all LED filaments 110 are arranged or provided outside (peripheral) of the central cylindrical space, C. In other words, the central cylindrical space, C, defines a (central) volume of the LED filament luminaire 100 in which no LED filament 110 is arranged or provided. For example, a volume of the central cylindrical space, Vc, and a volume of the enclosure, VE, may fulfil Vc > 0.1-VE, and even more preferred Vc > 0.25-VE.

[0051] Fig. 5 schematically shows a LED filament luminaire 100 according to an exemplifying embodiment of the present invention. The LED filament luminaire 100 has many features in common with the LED filament luminaire 100 as exemplified in Fig. 2, and it is hereby also referred to Fig. 2 and the associated text for an increased understanding of the LED filament luminaire 100. The LED filament luminaire 100 in Fig. 5 has, in contrast to the LED filament luminaire 100 of Fig. 2, a polygon-shaped (more specifically, square) enclosure 200. Furthermore, the four LED filaments 110 of the LED filament luminaire 100 arranged within the square-shaped enclosure 200 are arranged in such a way that at least two LED filaments 110 intersect, seen in a projection parallel to the principal axis, A. More specifically, according to this example, each LED filament 110 is intersected twice by two other (different) LED filaments 110. It should be noted that the number of intersections, and also, the number of LED filaments 110, may be arbitrary, and that Fig. 5 hereby merely discloses one embodiment / example of many of the LED filament luminaire 100. The LED filament luminaire 100 in Fig. 5 further comprises the feature that any LED filament 110 of the plurality of LED filaments 110 is connected between a first side wall portion 220a-d and a second side wall portion 220a-d, wherein the first side wall portion 220a-d and the second side wall portion 220a-d are not oppositely arranged in a direction, B, perpendicular to the principal axis, A. As shown in Fig. 5, the two LED filaments 110 connected to the (a) first side wall portion 220a are respectively connected to (the) second side wall portions 220b and 220d, whereby (the) second side wall portions 220b and 220d are not oppositely arranged the first side wall portion 220a in (any) direction, B, perpendicular to the principal axis, A. Furthermore, as the two LED filaments 110 connected to the (a) first side wall portion 220a are respectively connected to (the) second side wall portions 220b and 220d, the LED filaments 110 are hereby connected between two adjacent side wall portions in a circumferential direction, F, perpendicular to the principal axis, A.

[0052] The LED filament luminaire 100 of Fig. 5 further comprises the feature of a central cylindrical space, C, which extends from the base to the light exit window of the LED filament luminaire 100. The central cylindrical space, C, extends around the principal axis, A, with a radius, R, perpendicular to the principal axis, A. The plurality of LED filaments 110 are arranged peripheral of the central cylindrical space, C. Hence, the central cylindrical space, C, defines a (central) volume of the LED filament luminaire 100, whereby all LED filaments 110 are arranged or provided outside (peripheral) of the central cylindrical space, C. In other words, the central cylindrical space, C, defines a (central) volume of the LED filament luminaire 100 in which no LED filament 110 is arranged or provided. For example, a volume of the central cylindrical space, Vc, and a volume of the enclosure, VE, may fulfil Vc > 0.1-VE, and even more preferred Vc > 0.25-VE.

[0053] Fig. 6 schematically shows an arrangement of LED filaments 110 of a LED filament luminaire 100 according to an exemplifying embodiment of the present invention. At least two LED filaments 110 of the plurality of LED filaments 110 are obliquely arranged with respect to a direction, B, perpendicular to the principal axis, A, of the LED filament luminaire 100. Hence, the LED filaments 110, which are arranged on (along) the side wall of the LED filament luminaire 100 may be inclined with respect to the direction, B. The plurality of electrical contacts of the LED filament luminaire, which are provided on an inner side of the side wall of the enclosure thereof, may hereby comprise at least two rows of electrical contacts, shown in Fig. 6 as an upper electrical contact row 550 and a lower electrical contact row 560. The LED filaments 100 may hereby be connected between electrical contacts of the upper electrical contact row 550 and a lower electrical contact row 560. It should be noted that the number of electrical contact rows and / or the (angular) inclination of the LED filaments is (are) arbitrary.

[0054] Fig. 7 schematically shows an installed LED filament luminaire 100 according to an exemplifying embodiment of the present invention. The LED filament luminaire 100 may be installed in a ceiling 550 of a room in a home, office, restaurant, museum, etc. For example, the LED filament luminaire 100 may be arranged in an opening and / or cavity of the ceiling 550, such that the LED filament luminaire 100 is arranged flush with the ceiling 550. Alternatively, the LED filament luminaire 100 may project from the ceiling 550. Fig. 7 discloses the light exit window 230 of the LED filament luminaire 100. It should be noted that the LED filament luminaire 100 may, alternatively, be arranged in a wall of the room, or provided as a floor lamp. The LED filament luminaire 100 may further comprise a controller (not shown) configured to individually control the LED filaments of the plurality of LED filaments. The controller, which may be any device, unit, or the like, may be able to control the luminous flux either by wire or via wireless technology. The LED filament luminaire 100 may be conveniently controlled, either automatically or manually (e.g. in case of a controller arranged on a wall of the room), such that a desired light distribution and / or aesthetic effect may be achieved.

[0055] 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. For example, one or more of the LED filaments, the clusters of LED filaments, etc., may have different shapes, dimensions and / or sizes than those depicted / described.

Claims

CLAIMS:

1. A light-emitting diode, LED, filament luminaire (100) configured to provide, in operation, LED filament luminaire light (105), the LED filament luminaire comprising a plurality of LED filaments (110) configured to emit LED filament light (115), wherein each LED filament of the plurality of LED filaments comprises an elongated carrier (120) comprising a first major surface (140), an array of a plurality of LEDs (150) arranged on the first major surface, an elongated encapsulant (160) covering the plurality of LEDs and at least partly the first major surface, a first electrode (170) arranged at a first LED filament end of the LED filament and a second electrode (180) arranged at a second LED filament end of the LED filament, opposite to the first LED filament end, for electrical connection of the LED filament, an enclosure (200) extending along a principal axis, A, comprising a base portion (210) having a reflective inner base surface (215), a side wall (220) circumferential of the base portion and having a reflective inner side wall surface (225), a light exit window (230), oppositely arranged the base portion, and a plurality of electrical contacts (240) provided on an inner side (250) of the side wall of the enclosure, wherein each LED filament of the plurality of LED filaments is connected to a respective pair of electrical contacts, comprising an anode (300) and a cathode (310), of the plurality of electrical contacts via the first electrode and the second electrode, and wherein the enclosure encloses the plurality of LED filaments and defines a mixing chamber (400) arranged to at least partially mix the LED filament light before exiting the LED filament luminaire through the light exit window as the LED filament luminaire light, wherein at least a major portion of the elongated encapsulant of each LED filament of the plurality of LED filaments is arranged at least at a first minimum distance, DI, from the base portion and at least at a second minimum distance, D2, from the side wall.

2. The LED filament luminaire according to claim 1, wherein the reflective inner base surface and the reflective inner side wall surface mutually differ in at least one of diffusivity and reflectivity.

3. The LED filament luminaire according to claim 1 or 2, wherein a third distance, D3, between the anode and the cathode along the side wall, and a fourth distance, D4, between a first electrode end, El, of the first electrode and a second electrode end, E2, of the second electrode, fulfil D3> D4.

4. The LED filament luminaire according to any one of the preceding claims, further comprising a flexible strip (500) arranged on the inner side of the side wall of the enclosure, wherein the flexible strip comprises the plurality of electrical contacts.

5. The LED filament luminaire according to claim 4, wherein the flexible strip comprises electrically conductive tracks (600) electrically connected to one or more electrical contacts of the plurality of electrical contacts.

6. The LED filament luminaire according to any one of the preceding claims, comprising a central cylindrical space, C, extending from the base to the light exit window, around the principal axis, A, with a radius, R, perpendicular to the principal axis, A, wherein the LED filaments are arranged peripheral of the central cylindrical space, C, and wherein a volume of the central cylindrical space, Vc, and a volume of the enclosure, VE, fulfil Vc > 0.25-VE.

7. The LED filament luminaire according to any one of the preceding claims, wherein the plurality of LED filaments, in a projection parallel to the principal axis, A, is arranged to form a polygon shape.

8. The LED filament luminaire according to any one of the preceding claims, wherein the LED filament luminaire is cylinder-shaped.

9. The LED filament luminaire according to any one of claims 1-7, wherein a cross-section of the LED filament luminaire, perpendicular to the principal axis, A, has a polygon shape, and at least one of any LED filament of the plurality of LED filaments is connected between a first side wall portion and a second side wall portion, wherein the first side wall portion and the second side wall portion are not oppositely arranged in a direction, B, perpendicular to the principal axis, A, and any LED filament of the plurality of LED filaments is connected between two adjacent side wall portions in a circumferential direction, F, perpendicular to the principal axis, A, is fulfilled.

10. The LED filament luminaire according to any one of the preceding claims, wherein at least two LED filaments of the plurality of LED filaments are arranged perpendicular to the principal axis, A.

11. The LED filament luminaire according to any one of claims 1-9, wherein at least two LED filaments of the plurality of LED filaments are obliquely arranged with respect to a direction, B, perpendicular to the principal axis, A.

12. The LED filament luminaire according to claim 10 or 11, wherein the at least two LED filaments of the plurality of LED filaments, in a projection parallel to the principal axis, A, intersect.

13. The LED filament luminaire according to any one of the preceding claims, wherein the first electrode, a LED filament portion between the first and second electrodes, and the second electrode, together form a U-shape.

14. The LED filament luminaire according to any one of the preceding claims, wherein at least one ofDI > 5mm and D2 > 5mm, and wherein the enclosure has a height, He, parallel to the principal axis, A, and a width, Ee, perpendicular to He, wherein 0.9-He > DI > 0.1-He and 0.4-Ee > D2 > 0.05-Ee, is fulfilled.

15. The LED filament luminaire according to any one of the preceding claims, further comprising a controller configured to individually control the LED filaments of the plurality of LED filaments.

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