A LED filament luminaire with a spiral-shaped LED filament

Abstract

A LED filament luminaire (1) comprising a reflector (2), a spiral-shaped LED filament (3) comprising a plurality of LEDs (4) arranged on an elongated carrier and configured for, in operation, emitting LED light (5), the spiral-shaped LED-filament (3) being at least partly arranged in the reflector (2), and a light exit window (6), the LED filament luminaire (1) being configured to, in operation emit LED filament luminaire light (7) through the light exit window (6), the spiral-shaped LED filament (3) comprising a LED filament pitch (PS), the reflector (2) comprising an inner surface (9), the inner surface (9) comprising a plurality of concave structures (8), the plurality of concave structures (8) being arranged in a spiraling pattern comprising a concave structure pitch (PC), and the LED filament pitch (PS) corresponds to the concave structure pitch (PC).

Description

[0001] A LED filament luminaire with a spiral-shaped LED filament

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a LED filament luminaire comprising a reflector, a spiral-shaped LED filament comprising a plurality of LEDs configured for, in operation, emitting LED light, the spiral-shaped LED-filament being at least partly arranged in the reflector, and a light exit window, the LED lamp being configured to, in operation emit LED lamp light through the light exit window.

[0004] BACKGROUND OF THE INVENTION

[0005] A trend in lighting is LED filament luminaires. An LED filament luminaire is a LED luminaire 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 light-emitting diodes.

[0006] WO 2022 / 101152 Al discloses a LED light unit for providing LED light, the LED light unit comprising a flexible printed circuit board (PCB) having a first longitudinal axis and a plurality of elongated light sources each having a second longitudinal axis. The plurality of elongated light sources is arranged on the flexible PCB such that none of the second longitudinal axes of the plurality of elongated light sources is parallel to the first longitudinal axis of the flexible PCB. The LED light unit further comprises a carrier, and the flexible PCB is bent along the first longitudinal axis such that each of the elongated light sources is arranged in the shape of a substantially circular arc, and the flexible PCB is subsequently at least partially attached to the carrier.

[0007] In CN213177755 U an LED filament lamp is disclosed that comprises a shell and at least one reflection device arranged in the shell, an LED filament is arranged in the center of the reflection device, the LED filament lamp is characterized in that the LED filament comprises at least one spiral strip-shaped filament, and a radiator matched with the spiral strip-shaped filament in shape is arranged below the spiral strip-shaped filament.

[0008] It is desired to improve the performance, functionality and / or appearance of LED filament luminaires. It is further desired to provide a LED filament luminaire which provides good collimation and visibility of the LED filament, and particularly of a spiral-shaped LED filament.

[0009] SUMMARY OF THE INVENTION

[0010] It is an object of the present invention to overcome this problem, and to provide a LED filament luminaire with one or more of an improved performance, functionality, and appearance.

[0011] It is further desired to provide a LED filament luminaire which provides good collimation and visibility of the LED filament, and particularly of a spiral-shaped LED filament.

[0012] According to a first aspect of the invention, this and other objects are achieved by means of a LED filament luminaire comprising a reflector forming a reflective chamber, that defines a volume, a spiral-shaped LED filament comprising a plurality of LEDs arranged on an elongated carrier and configured for, in operation, emitting LED light, the spiralshaped LED-filament being at least partly arranged in the reflector and enclosed by the volume, and a light exit window, the LED filament luminaire being configured to, in operation emit LED filament luminaire light through the light exit window, where the spiralshaped LED filament comprises a LED filament pitch, PS, where the reflector comprises an inner surface, the inner surface comprising a plurality of concave structures, where the plurality of concave structures are arranged in a spiraling pattern comprising a concave structure pitch, PC, and where the LED filament pitch, PS, corresponds to the concave structure pitch, PC.

[0013] As used herein, the term “correspond”, such as when used in the connection that the LED filament pitch, PS, corresponds to the concave structure pitch, PL, is intended to mean equal to or within + / - 2 mm, or equal to or within + / - 1 mm, or equal to or within + / - 0.5 mm.

[0014] As used herein, the term LED filament pitch, PS, is intended to refer to the pitch of the loops of the spiral-shaped LED filament.

[0015] Thereby, and particularly by providing that the inner surface of the reflector comprises a plurality of concave structures, that the plurality of concave structures are arranged in a spiraling pattern comprising a concave structure pitch, PC, and that the LED filament pitch, PS, corresponds to the concave structure pitch, PC, a LED filament luminaire is provided with one or more of an improved performance, functionality, and appearance. Furthermore, such a LED filament luminaire provides an improved collimation of the LED filament luminaire light and an improved visibility of the LED filament, and particularly of a spiral-shaped LED filament.

[0016] The reflector may form a single reflective chamber, such as to provide a reflector having a particularly simple structure and which may be made in one piece. This chamber forms a volume that may enclose the spiral-shaped filament entirely or at least partly.

[0017] The LED filament pitch, PS, and the concave structure pitch, PL, may be provided with respective sizes being within + / - 2 mm of one another, or within + / - 1 mm of one another, or within + / - 0.5 mm of one another, or being equal to one another.

[0018] The LED filament luminaire comprises a longitudinal axis, L, the plurality of concave structures may be arranged in a concave structure angle, 0C, with respect to a transversal axis, T, extending perpendicular to the longitudinal axis, L, the spiral-shaped LED filament may be arranged in an LED filament angle, 0S, with respect to the transversal axis T, and the concave structure angle, 0C, may correspond to the LED filament angle, 0S.

[0019] The concave structure angle, 0C, and the LED filament angle, 0S, may be provided with respective sizes being within + / - 2 degrees of one another, or within + / - 1 degree of one another, or within + / - 0.5 degree of one another, or being equal to one another.

[0020] Thereby, a LED filament luminaire is provided with which the spiral-shaped LED filament is held in place in a particularly simple, efficient, and durable manner. Such a LED filament luminaire furthermore provides a uniform and aesthetically pleasing light output. Such a LED filament luminaire is still further particularly simple to assemble.

[0021] The shortest distance, D, between the inner surface of the reflector and a portion of the spiral-shaped LED filament is at least 1 cm. Alternatively, or additionally, the distance, D may be smaller than 2 cm, or smaller than 5 cm.

[0022] Thereby, a LED filament luminaire is provided with which the spiral-shaped LED filament is particularly well visible when the plurality of LEDs emit light.

[0023] The spiral-shaped LED filament may be partly arranged in the reflector. Alternatively, half of the spiral-shaped LED filament may be arranged in the reflector.

[0024] Thereby, a LED filament luminaire is provided with which the spiral-shaped LED filament is visible at large viewing angles when the plurality of LEDs emit light.

[0025] The spiral-shaped LED filament may be fully recessed in the reflector.

[0026] Thereby, a LED filament luminaire is provided with which the collimation of the LED filament luminaire light is improved to a particularly high degree. A gap, G, may be provided between the light exit window of the LED filament luminaire and a LED filament portion being closest to the light exit window, and the gap, G, may be less than 2 cm. Alternatively, the gap G may be less than 1.5 cm or less than 1 cm. Alternatively, or additionally, the gap G may be more than 0.5 cm or more than 1 cm.

[0027] Thereby, a LED filament luminaire is provided with which the spiral-shaped LED filament is particularly well visible at larger viewing angles when the plurality of LEDs emit light.

[0028] The reflector may be tapering towards an end opposite to the light exit window of the LED filament luminaire, the tapering part of the reflector may be elongated, and the reflector may at a position near or at the exit window be round in cross-section.

[0029] Thereby, a LED filament luminaire is provided which may be adapted to the preference of the customer.

[0030] The spiral-shaped LED filament comprises a plurality of X loops, where X may be an integer being in a range from 2 to 7. Alternatively, X may be an integer being in a range from 2 to 6. Alternatively, X may be an integer being in a range from 3 to 5.

[0031] Providing the spiral-shaped LED filament with such a number of loops has been shown to provide the best fit with the reflector.

[0032] The reflector may be a specular reflective reflector.

[0033] Thereby, a LED filament luminaire is provided with which the collimation of the LED filament luminaire light is improved to a particularly high degree, and further with which loss of light at the reflector surface is minimized.

[0034] The plurality of concave structures may comprise a parabolic shape.

[0035] Thereby, a LED filament luminaire is provided with which the collimation of the LED filament luminaire light is improved to a particularly high degree.

[0036] The LED filament pitch, PS, and the concave structure pitch, PC, may be in a range from 0.5 to 5 cm, or in a range from 1 to 4 cm, or in a range from 1 to 3 cm.

[0037] By thus keeping the LED filament pitch, PS, and the concave structure pitch, PC, relatively small, a LED filament luminaire with a more uniform light output is achieved.

[0038] The concave structure angle, 0C, and the LED filament angle, 0S, may be in a range from 2 to 45 degrees, or in a range from 4 to 35 degrees, or in a range from 5 to 30 degrees.

[0039] Thereby, a LED filament luminaire is provided with an improved performance and / or appearance. Especially, with such a LED filament luminaire the spiral-shaped LED filament is very well visible, also at relatively large viewing angles, when the plurality of LEDs emit light.

[0040] The number of concave structures may be from 2 to 7, or from 2 to 6, or from 3 to 5.

[0041] Such a number of concave structures has been shown to provide a wellfunctioning compromise between the LED filament luminaire being compact and being provided with an improved performance and / or appearance.

[0042] The number of concave structures and the number of loops may be the same. Thereby, LED filament luminaire with a compact structure is provided for.

[0043] The LED filament may be arranged at least partly in the plurality of concave structures. Alternatively, or additionally, the loops of the spiral-shaped LED filament may be located halfway in the plurality of concave structures.

[0044] Thereby, a LED filament luminaire is provided with which the spiral-shaped LED filament is visible at large viewing angles when the plurality of LEDs emit light.

[0045] Neighboring concave structures may be separated by a protruding part of the reflector.

[0046] Thereby, a LED filament luminaire is provided with which the spiral-shaped LED filament is held in place in a particularly simple, efficient, and durable manner.

[0047] The reflector may be a cup-shaped structure with a cavity for receiving the spiral shaped LED filament.

[0048] Thereby, a LED filament luminaire is provided with a reflector having a particularly simple structure. Such a LED filament luminaire is furthermore particularly simple to assemble.

[0049] Neighboring concave structures of the plurality of concave structures may be connected to one another. More particularly, sides of neighboring concave structures of the plurality of concave structures may be connected to one another.

[0050] The plurality of concave structures may be arranged in such a spiraling pattern that they face the light exit surface.

[0051] The light exit surface may be a flat surface. The light exit surface may comprise a diffusor.

[0052] The LED filament luminaire may be a spotlight or a downlight.

[0053] The present invention further relates to a spotlight or a downlight comprising a LED filament luminaire according to the invention. It is noted that the invention relates to all possible combinations of features recited in the claims.

[0054] BRIEF DESCRIPTION OF THE DRAWINGS

[0055] 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.

[0056] Fig. 1 shows a schematical perspective view of a LED filament luminaire according to the invention.

[0057] Fig. 2 shows a top view of the LED filament luminaire according to Fig. 1.

[0058] Fig. 3 shows a cross-sectional side view of the LED filament luminaire according to Fig. 1.

[0059] Fig. 4 shows a schematical perspective view of a spotlight comprising a LED filament luminaire according to the invention.

[0060] Fig. 5 shows a schematical perspective view of another LED filament luminaire according to the invention.

[0061] Fig. 6 shows a schematical perspective view of another LED filament luminaire according to the invention.

[0062] Fig. 7 shows a polar plot of the intensity of the light output resulting from a prior art LED filament luminaire with a naked LED filament.

[0063] Fig. 8 shows a polar plot of the intensity of the light output resulting from a LED filament luminaire according to the invention.

[0064] 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.

[0065] DETAILED DESCRIPTION

[0066] 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. Reference is first made to Figs. 1-3 showing a LED filament luminaire 1 according to the invention. Fig. 1 shows a schematical perspective view of the LED filament luminaire 1, Fig. 2 shows a top view of the LED filament luminaire 1 and Fig. 3 shows a cross-sectional side view of the LED filament luminaire 1.

[0067] Generally, and irrespective of the embodiment, the LED filament luminaire 1 comprises a reflector 2, a spiral-shaped LED filament 3 and a light exit window 6. As is illustrated on Fig. 2, the LED lamp 1 is configured to, in operation, emit LED lamp light 7 through the light exit window 6 in a main direction of emission M.

[0068] The light exit window 6 may be a flat surface. The light exit window 6 may be an open face. The light exit window 6 may be a transparent element. The light exit window 6 may comprise a diffusor.

[0069] The spiral-shaped LED filament 3 comprises a plurality of LEDs 4 (cf. Figs. 2 and 3). The spiral-shaped LED-filament 3 is arranged at least partly in the reflector 2. Particularly, half of the spiral-shaped LED filament 3 may be arranged in the reflector 2. Alternatively, the spiral-shaped LED filament 3 may be fully recessed in the reflector 2. The spiral-shaped LED filament 3 comprises a LED filament pitch PS. The spiral-shaped LED filament 3 comprises a plurality of X loops 13, where X is an integer which for instance may be in a range from 2 to 7, from 2 to 6, or from 3 to 5. In the embodiment shown, three loop 13 are provided.

[0070] The plurality of LEDs 4 are configured for, in operation, emitting LED light 5 (cf. Figs. 2 and 3). The plurality of LEDs 4 may be any suitable type of LEDs, such as white LEDs or RGB LEDs. The plurality of LEDs 4 may comprise any suitable number of LEDs.

[0071] The reflector 2 is specular reflective. The reflector 2 may be made of a suitable metal, such as aluminum. Alternatively, the reflector 2 may comprise a layer or a coating of a specular reflective material. The reflector 2 may form a single reflective chamber. Alternatively, the reflector may be made in more than one piece. The reflector 2 comprises an inner surface 9. The inner surface 9 comprises a plurality of concave structures 8. The plurality of concave structures 8 comprise a parabolic shape. The reflector 2 may be a cupshaped structure with a cavity formed by the inner surface 9 and the plurality of concave structures 8 for receiving the spiral shaped LED filament 3. The plurality of concave structures 8 are arranged in a spiraling pattern, which spiraling pattern comprises a concave structure pitch PC. The plurality of concave structures 8 are arranged in such a spiraling pattern that they face the light exit surface 6 or reflect light predominantly towards the light exit surface 6. The LED filament pitch PS corresponds to the concave structure pitch PC. For instance, the LED filament pitch PS and the concave structure pitch PC may be equal to one another. For instance, the LED filament pitch PS and the concave structure pitch PC may both be in a range from 0.5 to 5 cm, from 1 to 4 cm, or from 1 to 3 cm. Neighboring concave structures 8 of the plurality of concave structures 8 may be connected to one another. More particularly, sides of neighboring concave structures 8 of the plurality of concave structures 8 may be connected to one another.

[0072] The reflector 2 comprises a first end 25 at which the light exit window 6 of the LED filament luminaire 1 is formed and a second end 12 opposite to the first end 25 and the light exit window 6. The reflector 2 is cylindrical. Alternatively, the reflector 2 may be tapering towards the second end 12. If the reflector 2 is tapering, the tapering part of the reflector 2 may be elongated. The reflector 2 is round in cross-section at least at a position near or at the exit window 6. The reflector 2 comprises a plurality of Y concave structures 8, where Y is an integer which for instance may be equal to the number X of the plurality of loops 13 of the LED filament 3. For instance, the number Y of concave structures 8 may be from 2 to 7, from 2 to 6 or from 3 to 5. In the embodiment shown, the number Y of concave structures 8 is three. In the embodiment shown in Figs. 1-3, the reflector 2 is open ended. That is, neither the first end 25 or light exit window 6, nor the second end 12, comprises any reflector part or other surface element or part. In other embodiments (cf. for instance Figs. 5 and 6) one or both of the first end 25 and the second end 12 may be closed. Neighboring concave structures 8 may be separated by a ridge or protruding part 16 of the inner surface 9 of the reflector 2. Alternatively, a ridge or protruding part 16 of the inner surface 9 of the reflector 2 may form a border or borderline between neighboring concave structures 8. Alternatively, a ridge or protruding part 16 of the inner surface 9 of the reflector 2 may form a side of the two neighboring concave structures 8 or may connect the two neighboring concave structures 8.

[0073] Referring particularly to Fig. 2, the LED lamp 1 further comprises a longitudinal axis L and a transversal axis T. The transversal axis T extends perpendicular to the longitudinal axis L. The plurality of concave structures 8 of the reflector 2 are arranged in a concave structure angle 0C with respect to the transversal axis T. The spiral-shaped LED filament 3 is arranged in an LED filament angle 0S with respect to the transversal axis T. The concave structure angle 0C corresponds to the LED filament angle 0S. For instance, the concave structure angle 0C and the LED filament angle 0S may be equal to one another. For instance, the concave structure angle 0C and the LED filament angle 0S may both be in a range from 2 to 45 degrees, from 4 to 35 degrees, or from 5 to 30 degrees. For instance, the concave structure angle 0C and the LED filament angle 0S may differ from each other by maximally 0.5 degrees, 1 degree or 2 degrees.

[0074] Referring especially to Fig. 1, the reflector 2 and the LED filament 3 comprise such respective sizes that is ensured that in an assembled condition of the LED filament luminaire 1, the shortest distance D between the inner surface 9 of the reflector 2 and a portion 10 of the spiral-shaped LED filament 3 is at least 1 cm. Optionally, it may also be ensured that the distance D is smaller than 3 cm.

[0075] Referring especially to Fig. 1, a gap G is provided between the light exit window 6 of the LED filament luminaire 1 and a LED filament portion 11 being closest to the light exit window 6 in an assembled condition of the LED filament luminaire 1. The gap G may be less than 2 cm.

[0076] Any LED filament luminaire 1 according to the present invention may be used in a spotlight. Alternatively, any LED filament luminaire 1 according to the present invention may be used in a downlight. Any LED filament luminaire 1 according to the invention may also be used in any other suitable type of lamp or lighting device.

[0077] Fig. 4 shows as an example a spotlight 20 comprising a LED filament luminaire 1. The spotlight 20 may further comprise a diffusor 15 and a rim 14. Both the diffusor 15 and the rim 14 are provided on the reflector 2 at the light exit window 6. The diffusor 15 serves to turn the LED filament luminaire light 7 into diffuse LED filament luminaire light 7’. The rim 14 serves to hold the diffusor 15 in place. The spotlight may further comprise a housing 17. The LED filament luminaire 1 is arranged in the housing 17. The LED filament luminaire 1 is thus invisible on Fig. 4 save for the light exit window 6. The rim 14 may form a part of or be integral with the housing 17. The spotlight 20 may further comprise a terminal 19 for connection to a source of electrical energy, such as mains. The spotlight 20 may further comprise a locking mechanism 18, such as a snap lock, for mounting and keeping in place the spotlight 20.

[0078] Fig. 4 further illustrates that the housing 17 is configured to receive a reflector 2 which is tapering towards the second end 12 of the reflector 2. To this end the housing 17 is also tapering, namely towards an end 21 opposite to the diffusor 15 and the light exit window 6. This is on Fig. 4 illustrated in terms of the two diameters dl and d2, where d2 is smaller than dl. By way of example, dl may be 185 mm and d2 may be 150 mm. The housing 17 also comprises a height h measured as the shortest distance from the rim 14 to the end 21. By way of example, the height h may be 80 mm. Finally, Fig. 4 illustrates the diffuse LED filament luminaire light 7’ emitted from the light exit surface 6 and through the diffusor 15 in a main direction of emission M.

[0079] Turning now to Fig. 5, a schematical perspective view of another LED filament luminaire 100 according to the invention is shown. The LED filament luminaire 100 differs from the LED filament luminaire 1 described above in relation to Figs. 1-3 only in virtue of the following features.

[0080] In the embodiment shown in Fig. 5, the reflector 2 is closed ended. That is, the first end 25 or light exit window 6 comprises a surface element or part 22 closing off the reflector 2. Likewise, the second end 12 comprises a surface element or part 23 closing off the reflector 2. The surface part 22 may be transparent such as to allow emission of the LED lamp light 7. Alternatively, the surface part 22 may be a diffusor or comprise diffusing particles or surface elements such as to convert the LED filament luminaire light 7 into diffuse filament luminaire light 7’. The surface part 23 may be made of the same material as the reflector 2. It is of course also feasible to omit either of the two surface parts 22 and 23, such as to provide a reflector 2 which is only closed at one end.

[0081] Turning now to Fig. 6, a schematical perspective view of another LED filament luminaire 101 according to the invention is shown. The LED filament luminaire 101 differs from the LED filament luminaires 1 and 100 described above in relation to Figs. 1-3 and 5 only in virtue of the following features.

[0082] In the embodiment shown in Fig. 6, the spiral-shaped LED filament 3 is fully recessed in the reflector 2. That is, no part of the spiral-shaped LED filament 3 protrudes above an upper edge 24 of the reflector 2.

[0083] In the embodiment shown in Fig. 6, the reflector 2 is closed ended. That is, the first end 25 or light exit window 6 comprises a surface element or part 22 closing off the reflector 2. Likewise, the second end 12 comprises a surface element or part 23 closing off the reflector 2. The surface part 22 may be transparent such as to allow emission of the LED lamp light 7. Alternatively, the surface part 22 may be a diffusor or comprise diffusing particles or surface elements such as to convert the LED filament luminaire light 7 into diffuse filament luminaire light 7’. The surface part 23 may be made of the same material as the reflector 2. It is of course also feasible to omit either of the two surface parts 22 and 23, such as to provide a reflector 2 which is only closed at one end.

[0084] Turning finally to Figs. 7 and 8, two different polar plots of the intensity of the light output resulting from a LED filament luminaire is shown. Fig. 7 shows a polar plot of the intensity of the light output resulting from a prior art LED filament luminaire with a naked LED filament. Fig. 8 shows a polar plot of the intensity of the light output resulting from a LED filament luminaire 1, 100 or 101 according to the invention.

[0085] As may be seen by comparing Figs. 7 and 8, the LED filament luminaire 1, 100 or 101 according to the invention provides for a considerably improved light output in terms of collimation and visibility of the spiral shaped LED filament 3.

[0086] 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.

[0087] 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

CLAIMS:

1. A LED filament luminaire (1) comprising: a reflector (2) forming a reflective chamber that defines a volume, a spiral-shaped LED filament (3) having a number of loops, comprising a plurality of LEDs (4) arranged on an elongated carrier and configured for, in operation, emitting LED light (5), the spiral-shaped LED-filament being at least partly arranged in the reflector and enclosed by the volume, and a light exit window (6), the LED filament luminaire being configured to, in operation emit LED filament luminaire light (7) through the light exit window, wherein the spiral-shaped LED filament (3) comprises a LED filament pitch (PS) defined as the pitch of the loops, wherein the reflector (2) comprises an inner surface (9), the inner surface comprising a plurality of concave structures (8), the plurality of concave structures (8) are arranged in a spiraling pattern comprising a concave structure pitch (PC), and the LED filament pitch (PS) corresponds to the concave structure pitch (PC), and wherein the LED filament luminaire comprises a longitudinal axis (L), wherein the plurality of concave structures (8) are arranged in a concave structure angle (0C) with respect to a transversal axis (T) extending perpendicular to the longitudinal axis (L), wherein the spiral-shaped LED filament (3) is arranged in an LED filament angle (0S) with respect to a transversal axis (T), and wherein the concave structure angle (0C) corresponds to the LED filament angle (0S).

2. A LED filament luminaire according to claim 1, wherein the shortest distance (D) between the inner surface (9) of the reflector (2) and a portion (10) of the spiral-shaped LED filament (3) is at least 1 cm.

3. A LED filament luminaire according to claim 2, wherein the distance (D) is smaller than 5 cm.

4. A LED filament luminaire according to any one of the above claims, wherein the spiral-shaped LED filament (3) is partly arranged in the reflector (2), or wherein half of the spiral-shaped LED filament is arranged in the reflector.

5. A LED filament luminaire according to any one of the above claims 1-3, wherein the spiral-shaped LED filament (3) is fully recessed in the reflector (2).

6. A LED filament luminaire according to claim 5, wherein a gap (G) is provided between the light exit window (6) of the LED filament luminaire and a LED filament portion (11) being closest to the light exit window, and wherein the gap (G) is less than 2 cm.

7. A LED lamp according to any one of the above claims, wherein the reflector (2) is tapering towards an end (12) opposite to the light exit window (6) of the LED filament luminaire, wherein the tapering part of the reflector is elongated, and wherein the reflector (2) at a position near or at the exit window (6) is round in cross-section.

8. A LED lamp according to any one of the above claims, wherein the spiralshaped LED filament (3) comprises a plurality of X loops (13), wherein X is an integer being in a range from 2 to 7, and / or wherein the number of concave structures (8) is from 2 to 7.

9. A LED lamp according to any one of the above claims, wherein the reflector (2) is specular reflective.

10. A LED lamp according to any one of the above claims, wherein the plurality of concave structures (8) comprise a parabolic shape.

11. A LED lamp according to any one of the above claims, wherein the LED filament pitch (PS) and the concave structure pitch (PC) is in a range from 0.5 to 5 cm.

12. A LED lamp according to any one of the above claims, wherein the concave structure angle (0C) and the LED filament angle (0S) is in a range from 2 to 45 degrees.

13. A LED filament luminaire according to any one of the above claims, wherein the LED filament is at least partly arranged in the plurality of concave structures (8) and / or wherein the loops (13) of the spiral-shaped LED filament are located halfway in the plurality of concave structures (8).

14. A spotlight or a downlight comprising a LED filament luminaire (1) according to any one of the above claims.

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