Led Filament

Abstract

A light emitting diode "LED" filament 100 is provided that is configured to emit LED filament light. The LED filament includes an LED filament 110 comprising an array 120 of a plurality of LEDs 130 configured to emit LED light 140 elongated along an axis A and an encapsulant 150 surrounding the array of LEDs, the encapsulant comprising an optically transparent material. The LED filament further comprises an elongated reflector 160 having a first reflectivity R1 configured to reflect the LED light, the reflector partially surrounding the encapsulant along the LED filament by partially surrounding a cross section CB perpendicular to the axis A of the LED filament in a radial direction R, such that the reflector defines at least one opening 180 along the LED filament, and the encapsulant is not covered by the reflector along the at least one opening.

Description

[Technical field]

[0001] The present invention relates generally to light emitting diode (LED) filaments. [Background technology]

[0002] The use of light-emitting diodes "LEDs" for lighting purposes continues to gain attention. Compared to incandescent, fluorescent, neon, etc., LEDs offer numerous advantages, such as longer operating life, reduced power consumption, and improved efficiency in terms of the ratio of light energy to heat energy.

[0003] Many LED filament lamps or devices in the prior art include LED filaments capable of producing warm white light. However, it is of interest to improve the characteristics of the light emitted from the LED filament, including the color (temperature) of the light, without compromising the appearance and / or decorative aspects of the LED filament and / or LED filament lamp.

[0004] It is therefore an object of the present invention to improve the characteristics of the light emitted from an LED filament, including the color (temperature) of the light, while providing a desired aesthetic appearance and / or decorative aspect of the LED filament and / or LED filament lamp. Summary of the Invention [Problem to be solved by the invention]

[0005] It is of interest to explore the possibility of combining one or more of the numerous advantages of an LED filament with an LED while improving the characteristics of the light emitted from the LED filament without compromising the appearance and / or decorative aspects of the LED filament and / or LED filament lamp. [Means for solving the problem]

[0006] This and other objects are achieved by providing an LED filament having the features set forth in the independent claims. Preferred embodiments are defined in the dependent claims.

[0007] Therefore, according to the present invention, there is provided an LED filament configured to emit LED filament light. The LED filament has an elongation axis A. The LED filament comprises at least one array of LEDs configured to emit LED light and an encapsulant surrounding the at least one array of LEDs, the encapsulant comprising an optically transparent material. The LED filament further comprises an elongated reflector having a first reflectivity R1 configured to reflect the LED light, the reflector partially surrounding the encapsulant along the LED filament by partially surrounding a cross section CB of the LED filament perpendicular to the axis A in a radial direction R, such that the reflector defines at least one opening along the LED filament, and the encapsulant is not covered by the reflector along the at least one opening.

[0008] Therefore, the present invention is based on the idea of ​​providing an LED filament in which the reflector partially surrounds the encapsulant, which in turn surrounds the array of LEDs, such that the LED light emanates along the LED filament through the openings of the reflector. The LED filament thereby provides an optical cavity. Thus, the LED filament can provide control of the color (temperature) of the light and provide an aesthetically pleasing appearance and / or decorative aspect of the LED filament, by transmitting the LED light through the openings of the reflector, which surround parts of the encapsulant (and LEDs) in one or more radial directions, while the reflector does not cover or surround the encapsulant (and LEDs) in one or more radial directions.

[0009] The present invention is further advantageous in that the LED filament may provide compelling LED illumination through LED filament features such as thin line LED illumination, improved mixing of LED light, and / or less LED light speckle compared to prior art configurations.

[0010] The present invention is further advantageous in that the many benefits of using LED technology may be combined with the attractive and appealing properties of LED filaments as disclosed.

[0011] The present invention is further advantageous in that the reflector defines a structure or pattern by surrounding portions of the encapsulant (and LED) in one or more radial directions and transmitting the LED light through openings in the reflector, which structure or pattern of the reflector contributes to the aesthetic appeal of the LED filament.

[0012] The present invention is further advantageous in that the LED filament of the present invention comprises relatively few components. The small number of components is advantageous in that the LED filament is relatively cheap to manufacture. Moreover, the small number of components of the LED filament means that it is easier to reuse, especially compared to devices or S that comprise a relatively large number of components that hinder easy disassembly and / or reuse operations.

[0013] The LED filament lamp comprises an LED filament. The LED filament in turn comprises at least one array of LEDs. The term "array" as used herein means a linear configuration or chain or the like of LEDs arranged on the LED filament. The LEDs may further be arranged, attached and / or mechanically coupled on / to a support or substrate for each LED filament, the support or substrate being configured to support the LEDs. The LEDs are configured to emit LED light, i.e. light emitted from the LEDs, during operation.

[0014] The LED filament further comprises an encapsulant surrounding at least one array of LEDs, the encapsulant comprising an optically transparent material. The term "encapsulant" as used herein means an elongated material, element, structure, etc., configured or arranged to at least partially surround, encapsulate, and / or enclose the array of LEDs of the LED filament. The term "optically transparent material" as used herein means a material, composition, and / or substance configured to transmit (i.e., transmit) light.

[0015] The LED filament further comprises an elongated reflector having a first reflectivity R1, configured to reflect the LED light. The reflector partially surrounds the encapsulant along the LED filament by partially surrounding a cross section CB perpendicular to the axis A of the LED filament in the radial direction R, such that the reflector defines at least one opening along the LED filament, and the encapsulant is not covered by the reflector along the at least one opening. Thus, the encapsulant, which also surrounds the LED array, includes a (first) portion that is surrounded by the reflector along the LED filament, and further includes a (second) portion that is not surrounded (i.e., not covered) by the reflector along the LED filament due to the opening in the reflector. In other words, the reflector is stripped of material such that an opening is provided.

[0016] According to an embodiment of the present invention, the LED filament may comprise at least one first array of a plurality of first LEDs configured to emit light having a first color temperature CT1 and at least one second array of a plurality of second LEDs configured to emit light having a second color temperature CT2, CT1 ≠ CT2. Preferably, CT2-CT1>300K, more preferably CT2-CT1>700K, even more preferably CT2-CT1>900K. Thus, the LEDs of the first array may be configured to emit light having a first color temperature CT1 that is different from the second color temperature CT2 of the light emitted by the LEDs of the second array. For example, the first color temperature CT1 may be relatively high and the second color temperature CT2 may be relatively low. This embodiment is advantageous in that the LED filament may provide a desired color temperature of the LED filament light through a difference in color temperature between the arrays of the LEDs. This embodiment is further advantageous in that the difference in color temperature between the array of LEDs can contribute even further to the aesthetic appeal of the LED filament during operation.

[0017] According to an embodiment of the present invention, at least one first array of a plurality of first LEDs may be configured to emit light having a first color temperature CT1, and at least one second array of a plurality of second LEDs may include a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs. Thus, the LEDs of the first array may be configured to emit light having a first color temperature CT1, and the second array may include so-called RGB (red, green, blue) LEDs. This embodiment is advantageous in that the LED filament may realize an efficient emission of LED filament light during operation and realize a decorative LED filament.

[0018] According to one embodiment of the present invention, the at least one opening is an elongated opening arranged along at least a portion of the length of the LED filament. The elongated opening of the elongated reflector is therefore provided along the LED filament along the axis A. This embodiment is advantageous in that the shape of the elongated opening may further contribute to the attractiveness of the LED filament light and / or the desired properties of the LED emission. For example, in case of a single (i.e. only one) elongated opening of the reflector, the LED filament may achieve a single-sided LED emission.

[0019] According to one embodiment of the present invention, the reflector may partially surround the cross section CB of the encapsulant in the radial direction R and define a first opening and a second opening symmetrically with respect to the radial direction R, the second opening being located opposite the first opening. Thus, the reflector partially surrounds the cross section CB of the encapsulant in the radial direction R and partially surrounds the cross section CB of the encapsulant symmetrically with respect to the radial direction R, the reflector defines a first opening and a second opening located opposite each other with respect to the cross section CB. Thus, when viewed from the cross section CB of the encapsulant of the LED filament, the center of the first opening and the center of the second opening are separated by an angle of 180°. This embodiment is advantageous in that the form of two (elongated) openings may further contribute to the attractiveness of the LED filament light and / or the desired properties of the LED emission. For example, in the case of two (elongated) openings of this reflector, the LED filament may realize a double-sided (opposite) LED emission.

[0020] According to one embodiment of the invention, the LED filament may include a sub-encapsulant at least partially surrounding at least one of the at least one array of LEDs, the sub-encapsulant including a light-transmitting material. In other words, the encapsulant of the LED filament may at least partially surround the sub-encapsulant, which in turn may at least partially surround one or more of the array of LEDs, the sub-encapsulant including a material, composition, and / or substance configured to transmit (i.e., transmit) light. This embodiment is advantageous in that the sub-encapsulant may contribute even further to the desired properties of the LED filament light.

[0021] According to one embodiment of the invention, at least one of the encapsulant and sub-encapsulant of the LED filament includes at least one of a luminescent material configured to at least partially convert LED light emitted from the plurality of LEDs into converted light and a light scattering material configured to scatter the LED light emitted from the plurality of LEDs. Thus, the encapsulant and / or sub-encapsulant, including a light-transmitting material, further includes a luminescent material configured to at least partially convert LED light emitted from the plurality of LEDs into converted light and / or a light scattering material configured to scatter the LED light emitted from the plurality of LEDs.

[0022] According to one embodiment of the present invention, the LED filament may further comprise a support configured to support a plurality of LEDs, the encapsulant at least partially surrounding the support, the support being at least one of light transmissive and light reflective. Thus, a support (e.g., a substrate) configured to support (mechanically and electrically) a plurality of LEDs may be at least partially surrounded by the encapsulant. Furthermore, the support may be light transmissive and / or light reflective. This embodiment is advantageous in that at least a portion of the LED light may be transmitted through the support, thereby further contributing to the lighting properties and / or decorative appearance of the LED filament.

[0023] According to an embodiment of the present invention, the LED filament may extend in at least one of a meandering shape, a spiral shape, and a helical shape in the plane P. Thus, the LED filament may extend in a meandering shape, a spiral shape, and / or a helical shape according to the above. By "meandering shape" is meant herein an "S" shape, a "snake" shape, etc., according to which the LED filament extends in the plane P. By "spiral shape" is meant herein an LED filament extends in a coil or corkscrew shape. By "spiral shape" is meant herein an LED filament may be wound around its own axis, i.e. around the axis A. It should be noted that any combination of the above examples may be feasible, such as a combination of a spiral shape and a helical shape. This embodiment is advantageous in that the configuration of the LED filament in the LED filament may achieve an effective emission of LED filament light during its operation and may achieve a decorative LED filament.

[0024] According to an embodiment of the present invention, the cross section CB of the LED filament may include a first central axis C passing through the center CP of the cross section CB and through the at least one opening. The LED filament may further have a second central axis B perpendicular to the first central axis C, the support being arranged parallel to the second central axis B and having a width Ws. The at least one opening has a width G parallel to the second central axis B, the width G of the at least one opening and the width Ws of the support satisfying G<0.5·Ws. Thus, the LED filament may comprise a support for supporting the LEDs of the array, the support being arranged parallel to the opening, the width G of the opening being less than half the width Ws of the support. Preferably, G<0.4·Ws, even more preferably, G<0.3·Ws. This embodiment is advantageous in that the relatively narrow opening may enable the LED filament to direct the LED light in a specific direction and / or in that a higher reflection is achieved before the light is emitted from the LED filament.

[0025] According to an embodiment of the present invention, the cross-section CB of the LED filament includes a first central axis C passing through the center CP of the cross-section CB and at least one opening. The cross-section CB further includes a second central axis B perpendicular to the first central axis C. The at least one opening has a width G parallel to the second central axis B, and the at least one array is arranged at a distance D from the first central axis C along the second central axis B, where D > G / 2. In other words, the array of LEDs is arranged offset from the first central axis C by a distance D, and the distance D is greater than half the width G of the opening. This configuration of the LED filament allows the array of LEDs to be further surrounded to a greater extent by the reflector, thus further enhancing the concept of the optical cavity of the present invention. Thereby, the LED filament may enable a relatively large portion of the LED light to be reflected via the reflector before the light is emitted from the LED filament.

[0026] According to an embodiment of the present invention, the cross-section CB of the LED filament includes a first central axis C passing through the center CP of the cross-section CB and at least one opening. The cross-section CB further includes a second central axis B perpendicular to the first central axis C. The height He of the encapsulant from the center CP to the at least one opening along the first central axis C and the width W of the LED filament along the second central axis B satisfy He < W. Therefore, the height He of the encapsulant is smaller than the width W of the LED filament.

[0027] According to an embodiment of the present invention, the first reflectivity R1 of the elongated reflector may satisfy R1 > 70%. Therefore, the reflector may have a relatively large reflectivity for reflecting LED light.

[0028] According to one embodiment of the present invention, the LED filament may include at least one diffuser disposed on at least one opening, and the at least one diffuser has a second reflectivity R2, and R2 < R1 - 20% is satisfied. The term "diffuser" as used herein means substantially any element, material, etc. configured to diffuse the light incident thereon. Therefore, according to this embodiment, the second reflectivity R2 is smaller than the first reflectivity R1. Thereby, the diffuser provided on the opening is partially reflective, that is, semi-reflective, and may have a reflectivity in the range of 30% to 80% with respect to visible light, for example. Therefore, the opening provided with the diffuser according to this embodiment is advantageous in that a further improvement in the mixing of the LED light is brought about by a part of the light incident on the opening being reflected back before the LED light exits from the LED filament through the opening of the reflector.

[0029] According to one embodiment of the present invention, an illumination device is provided. The illumination device may include an LED filament according to any one of the foregoing embodiments and a cover including at least a partially light-transmissive material, the cover at least partially surrounding the LED filament. The illumination device may further include an electrical connection portion connected to the LED filament for supplying power to the plurality of LEDs of the LED filament.

[0030] By considering the following detailed disclosure, drawings, and appended claims, further objects, features, and advantages of the present invention will become apparent. Those skilled in the art will understand that various features of the present invention can be combined to create embodiments other than those described below.

Brief Description of the Drawings

[0031] Next, this and other aspects of the present invention will be described in more detail with reference to the accompanying drawings showing embodiments of the present invention. [Figure 1] Shows an LED filament lamp according to the prior art. [Diagram 2] 1 illustrates an LED filament according to an exemplary embodiment of the present invention. [Figure 3a] 1 illustrates an LED filament of an LED filament configuration according to an exemplary embodiment of the present invention. [Figure 3b] 1 illustrates an LED filament of an LED filament configuration according to an exemplary embodiment of the present invention. [Figure 3c] 1 illustrates an LED filament of an LED filament configuration according to an exemplary embodiment of the present invention. [Figure 4] 1 illustrates an LED lighting device with an LED filament configuration according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] FIG. 1 shows a prior art LED filament lamp 10 with a number of LED filaments 20. This type of LED filament lamp 10 is highly valued because it is highly decorative and because it offers many advantages compared to incandescent lamps, such as a longer operating life, reduced power consumption, and improved efficiency in terms of the ratio of light energy to heat energy. This type of LED filament lamp 10 is capable of producing warm white light. However, it is of interest to improve the characteristics of the light emitted from the LED filament 20 without compromising the appearance and / or decorative aspects of the LED filament 20 and / or the LED filament lamp 10.

[0033] FIG. 2 illustrates an LED filament 110 according to an exemplary embodiment of the present invention. The LED filament 110 is configured to emit LED filament light 140. The LED filament 110 includes an LED filament 110 elongated along an axis A, such that FIG. 2 illustrates the LED filament 110 in a cross section perpendicular to the axis A. Although the LED filament 110 includes two arrays 120 of a plurality of LEDs 130 configured to emit LED light 140, it should be noted that the LED filament 110 may include substantially any number of arrays 120, such as a (single) array of LEDs, a plurality of arrays of LEDs, etc. The plurality of LEDs 130 preferably includes 6 or more LEDs, more preferably 9 or more LEDs, and even more preferably 11 or more LEDs. The plurality of LEDs 130 may be direct-emitting LEDs that provide color. Preferably, the LED filament 120 has a length L (not shown) and a width W (not shown), where L>5W.

[0034] In the embodiment of the LED filament 110 of FIG. 2, the LED filament 110 comprises a first array 120a of a first plurality of LEDs 130a as well as a second array 120b of a second plurality of LEDs 130b. Thus, the LED filament 110 comprises two rows of LEDs 130a, 130b. The first plurality of LEDs 130a and the second plurality of LEDs 130b may be of the same type or may differ from each other by one or more characteristics. For example, the first array 120a of the first plurality of LEDs 130a may be configured to emit light having a first color temperature CT1, and the second array 120b of the second plurality of LEDs 130b may be configured to emit light having a second color temperature CT2, the first color temperature and the second color temperature being different, i.e. CT1 ≠ CT2. Preferably, CT2-CT1>300K, more preferably, CT2-CT1>700K, and even more preferably, CT2-CT1>900K.

[0035] According to another embodiment, the first array 120a of the plurality of first LEDs 130a may be configured to emit light having a first color temperature CT1, and the second array 120b of the plurality of second LEDs 130b may include a plurality of red, green, blue (and white) LEDs, i.e., RGB(W) LEDs.

[0036] The LED filament 110 further comprises an encapsulant 150. The encapsulant 150, which has an elongated shape and comprises a light-transmitting material, surrounds the array 120 of the LEDs 130. The cross section CB of the LED filament 110, and in this case also the encapsulant 150, may have, for example, an elliptical shape. The cross section CB of the encapsulant 150 perpendicular to the axis A may be semicircular or circular. The encapsulant 150 may be a polymer material, which may be flexible, for example silicone. The encapsulant 150 may include a luminescent material configured to at least partially convert the LED light into converted light. The luminescent material may be a polymer matrix including a light-scattering material, for example BaSO4 particles, Al2O3 particles, and / or TiO2 particles. The luminescent material may be a phosphor, such as an inorganic phosphor (e.g. YAG, LuAG, ECAS, KSiF, etc.) and / or a quantum dot or a quantum rod. The phosphor may further be, for example, a (blue) green / yellow and / or red phosphor, such that the luminescent material may be configured, for example, to convert UV LED light to blue converted light and / or UV / blue LED to green / yellow and / or red converted light. Although not shown in FIG. 2, the thickness of the encapsulant 150 and / or the concentration of the luminescent material therein may vary over the length of the LED filament 110 along axis A.

[0037] The LED filament 110 further comprises a sub-encapsulant 200 at least partially surrounding the first array 120a of the first plurality of LEDs 130a. The sub-encapsulant 200, which comprises an optically transparent material, may be different from the material of the encapsulant 150. It is noted that the second array 120b of the second plurality of LEDs 130b may also comprise a sub-encapsulant, which may further comprise the same material as the sub-encapsulant 200 or a different material.

[0038] The LED filament 110 of FIG. 2 further comprises an elongated reflector 160 extending along the elongated LED filament 110. The reflector 160 is configured to reflect LED light emitted from the array 120 of the LEDs 130 of the LED filament 110 during operation. When viewed at a cross section CB of the LED filament 110, the reflector 160 partially surrounds the encapsulant 150 perpendicular to the axis A of the LED filament 110 in a radial direction R. The reflector 160 defines one or more openings 180 along the LED filament 110, and the encapsulant 150 is not covered by the reflector 150 along the openings 180. As illustrated at the top of FIG. 2, the reflector 160 defines a (single) opening 180 (facing upwards) and extends along the axis A of the LED filament 110. Thereby, there is a single-sided emission of the LED filament light 140 from the LED filament 110. As illustrated in the lower part of FIG. 2, the reflector 160 defines two openings 180 (upward and downward) extending along the axis A of the LED filament 110. This allows for a two-sided (opposite) emission of the LED filament light 140 from the LED filament 110. The elongated reflector 160 may include reflective particles and / or reflective flakes in a polymer material / matrix. The reflector 160 and / or the polymer material / matrix may be flexible. For example, the polymer may be a silicone material. Furthermore, the first reflectivity R1 of the elongated reflector may satisfy R1>70%, more preferably >80%, and even more preferably >85%.

[0039] In Fig. 2, the LED filament 110 comprises a support 210 configured to support an array 120 of a plurality of LEDs 130. Preferably, the LEDs 130 are arranged on an elongated support 210, for example a substrate, which may be rigid (for example made of a polymer, glass, quartz, metal or sapphire) or flexible (for example made of a polymer or metal, for example a film or (polyimide) foil). The support 210 may be monolithic or may have electrical tracks. If the support 210 comprises a first main surface and an opposite second main surface, the array 120 of a plurality of LEDs 130 may be arranged on at least one of these surfaces. The encapsulant 150 at least partially surrounds the support 210. The support 210 may be reflective and / or light-transmitting, such as translucent and preferably transparent. For example, the support 210 may have a reflectivity of, for example, greater than 80% and / or a light transmittance of, for example, greater than 50%.

[0040] As illustrated in FIG. 2, the LED filament 110 may have certain preferred dimensions as follows. The cross-section CB of the LED filament 110 (and thus also of the encapsulant 150) may include a first central axis C passing through the center CP of the cross-section CB and the opening 180 of the reflector 160. The LED filament 110 may further have a second central axis B perpendicular to the first central axis C. The support 210 is arranged parallel to (along) the second central axis B and has a width Ws. The opening 180 has a width G parallel to the second central axis B, and the width G of the opening 180 and the width Ws of the support 210 satisfy G < 0.5·Ws. For example, Ws < 10 mm, and thus G < 5 mm, but it is even more preferable that G < 3 mm. Further, the array 120 of a plurality of LEDs 130 is arranged at a distance D from the first central axis C parallel to (along) the second central axis B, and D > G / 2. Preferably, D > 3·G / 4, and even more preferably, D > G. Further, the height He of the encapsulant 150 from the center CP to the opening 180 of the reflector 160 along the first central axis C and the width W of the LED filament 110 along the second central axis B satisfy He < W. Preferably, He < 3·W / 4, and even more preferably, He < W / 2.

[0041] FIGS. 3a to 3c show the LED filament 110 of the LED filament configuration 100 according to an exemplary embodiment of the present invention. More specifically, FIGS. 3a to 3c show various geometric examples or geometric configurations of the LED filament 110 of FIG. 2, and reference is made to FIG. 2 and the related text to deepen the understanding of the components and / or functions of the LED filament 110 and / or the LED filament configuration 100.

[0042] In FIG. 3a, the LED filament 110 including a plurality of LEDs 130 of the LED filament configuration 100 extends in a meandering shape within a plane P defined by an axis A and an axis B. Therefore, according to this embodiment, the LED filament 110 extends in a "S-shaped" or "snake-shaped" manner within the plane P.

[0043] In Fig. 3b, the LED filament 110 of the LED filament configuration 100 comprising the plurality of LEDs 130 is elongated in a spiral shape. Thus, according to this embodiment, the LED filament 110 is elongated in a coil or corkscrew shape, and the plurality of LEDs 130 are configured to emit light in an essentially vertical direction (upwards) with respect to the presentation (orientation) of the LED filament 110 in Fig. 3a.

[0044] In Fig. 3c, the LED filament 110 comprising the plurality of LEDs 130 of the LED filament configuration 100 is elongated in a helical shape, the LED filament being wound about an axis A. Thus, according to this embodiment in which the LED filament is wound around its own axis, i.e. around axis A, the plurality of LEDs 130 are configured to emit light upwards, downwards and / or sideways with respect to the presentation (orientation) of the LED filament 110 in Fig. 3a.

[0045] 4 shows a schematic diagram of a lighting device 300 according to an embodiment of the present invention. The lighting device 300, which may constitute a lamp or a luminaire, comprises an LED filament arrangement 100 or an LED filament 110 according to any one of the previous embodiments. The lighting device 300 further comprises a cover 310, illustrated as being bulb-shaped. The cover 310 may comprise an at least partially light-transmitting (e.g. transparent) material and at least partially surrounds the LED filament arrangement 100 or the LED filament 110. The lighting device 300 further comprises an electrical connection 320, which is connected to the LED filament arrangement 100 or the LED filament 110 for the supply of power to the LEDs of the LED filament arrangement 100 or the LED filament 110.

[0046] Those skilled in the art will appreciate that the present invention is in no way limited to the preferred embodiment described above. Rather, many modifications and variations are possible within the scope of the appended claims. For example, one or more of the LED filament 110, the encapsulant 150, the reflector 160, etc. may have different shapes, dimensions, and / or sizes than those shown / described.

Claims

1. A light-emitting diode “LED” filament configured to emit LED filament light, an elongation axis A, at least one array of a plurality of light-emitting diodes “LEDs” configured to emit LED light, an encapsulant surrounding the at least one array of the plurality of LEDs, the encapsulant including a light-transmissive material, a support configured to support the plurality of LEDs, the encapsulant at least partially surrounding the support, the support being at least one of light-transmissive and reflective, wherein the LED filament, A first reflector having a reflectivity R configured to reflect the LED light １ which is an elongated reflector, and the reflector partially surrounds the encapsulant along the LED filament by partially surrounding a cross-section CB perpendicular to the axis A of the LED filament in the radial direction R and is in direct contact with the encapsulant and the support, whereby the reflector defines at least one opening along the LED filament, and the encapsulant is not covered by the reflector along the at least one opening. An LED filament further comprising a reflector.

2. The first color temperature CT １ at least one first array of a plurality of first LEDs configured to emit light having at least one second array of a plurality of second LEDs, and comprising, wherein the second array has a color temperature CT １ ≠ CT ２ and emits light having a second color temperature CT ２ or the second array includes a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs the LED filament according to claim 1.

3. The LED filament according to claim 1 or 2, wherein the at least one opening is an elongated opening disposed along at least a portion of the length of the LED filament.

4. The LED filament according to claim 1 or 2, wherein the reflector partially surrounds the cross-section CB of the encapsulant in the radial direction R and defines a first opening and a second opening by being symmetric with respect to the radial direction R, and the second opening is disposed on the opposite side of the first opening.

5. A sub-encapsulant at least partially surrounding at least one of the at least one array of the plurality of LEDs, the sub-encapsulant including a light-transmissive material, the LED filament according to claim 1 or 2 comprising the sub-encapsulant.

6. The LED filament according to claim 5, wherein at least one of the encapsulant and the sub-encapsulant includes a luminescent material configured to at least partially convert the LED light emitted from the plurality of LEDs into converted light and / or a light-scattering material configured to scatter the LED light emitted from the plurality of LEDs.

7. wherein the LED filament, extends in at least one of a meandering shape, a spiral shape, and a helical shape in a plane P. a spiral shape, and The LED filament according to claim 1 or 2, extending in at least one of the above shapes.

8. wherein the cross-section CB of the LED filament, a first central axis C passing through the center CP of the cross-section CB and the at least one opening, including a second central axis B perpendicular to the first central axis C; The support is arranged parallel to the second central axis B and has a width Ws, the at least one opening has a width G parallel to the second central axis B, and the width G of the opening and the width Ws of the support satisfy G < 0.5·Ws. The LED filament according to claim 1 or 2.

9. The cross-section CB of the LED filament is including a first central axis C passing through the center CP of the cross-section CB and the at least one opening; including a second central axis B perpendicular to the first central axis C; The at least one opening has a width G parallel to the second central axis B, and the at least one array is arranged at a distance D from the first central axis C along the second central axis B, and D > G / 2. The LED filament according to claim 1 or 2.

10. The cross-section CB of the LED filament is including a first central axis C passing through the center CP of the cross-section CB and the at least one opening; including a second central axis B perpendicular to the first central axis C; The height He of the encapsulant from the center CP to the at least one opening along the first central axis C and the width W of the LED filament along the second central axis B satisfy He < W. The LED filament according to claim 1 or 2.

11. the first reflectance R of the elongated reflector １ is R １ The LED filament according to claim 1 or 2, satisfying R １ > 70%.

12. At least one diffuser disposed on the at least one opening, wherein the at least one diffuser has a second reflectance R ２ and R ２ < R １ - 20% is satisfied, the LED filament according to claim 1 or 2, comprising a diffuser.

13. An illumination device, comprising: an LED filament configuration having the LED filament according to claim 1 or 2; a cover at least partially made of a light-transmissive material, the cover at least partially surrounding the LED filament configuration; an electrical connection part connected to the LED filament configuration for supplying power to the plurality of LEDs of the LED filament configuration.

Images