LED filament

Abstract

The present invention relates to an LED filament 10 comprising: a support 16; a plurality of first blue LEDs 22 disposed on the support and adapted to emit first blue light 24; a first elongated encapsulant 26 covering the first blue LEDs and at least a portion of the support, the first elongated encapsulant 26 having a first luminescent material 28 configured to convert at least a portion of the first blue light into first converted light 30; and an LED filament 14 including a top surface 34 on or above the first elongated encapsulant, the LED filament further comprising a string 36, 36′ of second blue LEDs 38 disposed on the top surface of the LED filament and adapted to emit second blue light 40, the light output surfaces 42 of the second blue LEDs facing away from the LED filament.

Description

Technical Field

[0001] The present invention relates to a light-emitting diode (LED) filament. The present invention also relates to a lamp or lighting fixture having such an LED filament. The present invention also relates to a lighting system having such a lamp or lighting fixture.

Background Art

[0002] The trend in lighting is the LED filament lamp. An LED filament lamp is an LED lamp designed to resemble a conventional incandescent bulb that has a visible filament for aesthetic and light distribution purposes but includes highly efficient light-emitting diodes.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to improve the performance and / or function of an LED filament.

Means for Solving the Problems

[0004] According to a first aspect of the present invention, this and other objects are achieved by a light-emitting diode (LED) filament, a plurality of first blue LEDs adapted to emit first blue light, the plurality of first blue LEDs being disposed on a carrier, and a first elongated encapsulant covering the plurality of first blue LEDs and at least a part of the carrier, the first elongated encapsulant having a first luminescent material configured to convert at least a part of the first blue light into first converted light, an LED filament having a first elongated encapsulant having an upper surface, a string of second blue LEDs adapted to emit second blue light, the string of second blue LEDs being disposed on the upper surface of the LED filament, and the light output surface of the second blue LEDs facing away from the LED filament.

[0005] In this method, optical crosstalk (i.e., the action by which the operating blue LED stimulates the phosphor converter of the LED filament, which then emits light of a different color) is reduced or eliminated, and therefore, pure blue light can be supplied.

[0006] Preferably, less than 5% of the light from the second blue LED is converted (by the first luminescent material), more preferably less than 3% of the light from the second blue LED is converted (by the first luminescent material), and most preferably less than 1%, for example 0%, of the light from the second blue LED is converted (by the first luminescent material).

[0007] The upper surface has a top surface area (TSA), and the string of the second blue LEDs has a string area (SA), where SA < 0.4 TSA, and in particular SA < 0.2 TSA. In this manner, the string of the second blue LEDs does not block and / or absorb (excessive amounts of) the first blue light and / or the first converted light.

[0008] The LED filament may further include a controller configured to individually control the emission of the first blue light from the plurality of first blue LEDs and the emission of the second blue light from the string of second blue LEDs. In this configuration, the LED filament can selectively supply white light, colored light, or a combination thereof.

[0009] The string of the second blue LEDs is arranged on or off a light-transmitting substrate. This allows the first blue light and / or the first converted light to easily pass through the string of the second blue LEDs, which is arranged above the first blue LEDs. The second blue LEDs and their electrical tracks may still block some light, but the first blue light and / or converted light passes through the light-transmitting substrate or very close to the second blue LEDs and their electrical tracks.

[0010] The string of the second blue LEDs may be covered with a second elongated encapsulant that does not contain any luminescent material or light-scattering material. In other words, the second elongated encapsulant does not contain any luminescent material or light-scattering material. In this configuration, the optical light distribution requirements of the LED filament can be met. The second elongated encapsulant may be, for example, dome-shaped.

[0011] The string of the second blue LEDs may have an LED pitch of less than 1000 μm, preferably less than 800 μm, more preferably less than 600 μm, and most preferably less than 500 μm. The "LED pitch" may be the distance between the centers of adjacent second blue LEDs in the string.

[0012] The LED filament may further have a plurality of red LEDs adapted to emit red light, and optionally a plurality of green LEDs adapted to emit green light, wherein the plurality of red LEDs and the optional plurality of green LEDs are arranged on the upper surface of the LED filament. Alternatively, the plurality of red LEDs and the optional plurality of green LEDs may be arranged on the support of the LED filament, for example, under or next to the first elongated encapsulant. The plurality of red LEDs and the optional plurality of green LEDs enable the LED filament to supply light of various colors. Accordingly, the controller may further be configured to individually control the emission of red light from the plurality of red LEDs and the emission of green light from any plurality of green LEDs.

[0013] The plurality of red LEDs and optionally the plurality of green LEDs may be arranged in at least one string, such as a string of red LEDs and another string of green LEDs, or a string of second blue LEDs, red LEDs and optionally green LEDs. Therefore, in one or more embodiments, the string of second blue LEDs includes only second blue LEDs. Also, in one or more embodiments, the string of second blue LEDs includes the plurality of red LEDs and optionally the plurality of green LEDs.

[0014] The first luminescent material may be configured to convert at least a portion of the first blue light, together with the first blue light emitted by the plurality of first blue LEDs that was not converted, into a first converted light including first green / yellow light and first red light that forms a first white light having a first correlated color temperature (CCT1). Preferably, CCT1 ≤ 2500K.

[0015] The filament circuit further comprises a plurality of third blue LEDs adapted to emit third blue light, the plurality of third blue LEDs arranged on the support, and a third elongated encapsulant covering the plurality of third blue LEDs and at least a portion of the support, the third elongated encapsulant having a second luminescent material configured to convert at least a portion of the third blue light into second converted light. In this configuration, the LED filament can still supply white light of various color temperatures while reducing or avoiding optical crosstalk.

[0016] The string of the second blue LEDs may be arranged at the boundary between the first elongated encapsulant and the third elongated encapsulant in order to reduce or minimize its influence on the first blue / converted light and the third blue / second converted light.

[0017] The second luminescent material may be configured to convert at least a portion of the third blue light, together with the third blue light emitted by the plurality of third blue LEDs that was not converted, into a second converted light including a second green / yellow light and a second red light that forms a second white light having a second correlated color temperature (CCT2) higher than the first correlated color temperature. Preferably, CCT2-CCT1 ≥ 500K, and more preferably, CCT2-CCT1 ≥ 1000K. Generally, CCT2 ≥ 3500K. Furthermore, the color rendering index (CRI) of the first white light and the second white light may be at least 80.

[0018] A second aspect of the present invention provides a lamp or lighting fixture having an LED filament according to the first aspect and an antenna functionally coupled to the controller of the LED filament. The antenna enables remote control of the lamp or lighting fixture. The lamp may be, for example, a (retrofit) light bulb.

[0019] A third aspect of the present invention is provided, a lighting system comprising a lamp or lighting fixture according to the second aspect, and at least one (remote) user interface for supplying user input and / or at least one (remote) sensor for detecting data, wherein the controller is configured to control the plurality of first blue LEDs and the plurality of second blue LEDs based on the user input and / or the data, and optionally control the plurality of red LEDs, the plurality of green LEDs and the plurality of third blue LEDs.

[0020] It should be noted that the present invention relates to all possible combinations of the features listed in the claims. [Brief explanation of the drawing]

[0021] Herein, these and other embodiments of the present invention will be described in more detail with reference to the accompanying drawings illustrating embodiments of the present invention. [Figure 1a]A cross-sectional view of an LED filament according to an embodiment of the present invention. [Figure 1b] A side view of the LED filament of FIG. 1a. [Figure 1c] A top view of the LED filament of FIG. 1a. [Figure 2a] LED filaments according to other embodiments of the present invention are illustrated. [Figure 2b] LED filaments according to other embodiments of the present invention are illustrated. [Figure 2c] LED filaments according to other embodiments of the present invention are illustrated. [Figure 2d] LED filaments according to other embodiments of the present invention are illustrated. [Figure 2e] LED filaments according to other embodiments of the present invention are illustrated. [Figure 3] A side view of an aspect of the present invention including a lamp.

[0022] The sizes of the layers and regions as illustrated in the figures may be exaggerated for purposes of explanation and are thus shown to illustrate the general structure of embodiments of the present invention. Throughout, like reference numerals refer to like elements.

Mode for Carrying Out the Invention

[0023] Here, the present invention will be described in more detail below with reference to the accompanying drawings showing presently preferred embodiments of the present invention. However, the present invention can be implemented in various forms and should not be construed as limited to the embodiments described herein. More precisely, these embodiments are shown for the purpose of completeness and perfection and to fully convey the scope of the present invention to those skilled in the art.

[0024] Figs. 1a to 1c illustrate an LED filament 10 according to an embodiment of the present invention. The LED filament 10 can supply LED filament (device) light 12.

[0025] The LED filament 10 has an LED filament 14. The LED filament 14 may be rigid or flexible.

[0026] The LED filament 14 has a support 16. The support 16 is generally a substrate. The support 16 is generally elongated. Preferably, the LED filament 14 has a length L, where L > 5D. The distance D corresponding to the width of the support 16 may be, for example, in the range of 0.5 to 5 mm. The support 16 may include two elongated edges 18a, 18b arranged at a distance D from each other, a first (main) surface 20a, and a second (main) surface 20b arranged on the opposite side of the first surface 20a. The support 16 may be rigid (for example, made from polymer, glass, quartz, metal, or sapphire) or flexible (for example, made from polymer or metal, such as film or foil).

[0027] The LED filament 14 further comprises a plurality of first blue LEDs 22 adapted to emit first blue light 24. The first blue light 24 may have a main peak wavelength in the wavelength range of, for example, 450 to 490 nm. The plurality of first blue LEDs 22 are arranged on a support 16. Specifically, the plurality of first blue LEDs 22 may be mounted on a first surface 20a of the support 16. Furthermore, the plurality of first blue LEDs 22 are preferably arranged in a linear array / string / single row, here on the longitudinal centerline of the support 16. The number of first blue LEDs 22 may be, for example, at least 10 or at least 20.

[0028] The LED filament 14 further comprises a plurality of first blue LEDs 22 and a first elongated encapsulant 26 covering at least a portion of the support 16. The first elongated encapsulant 26 has a first luminescent material 28 configured to convert at least a portion of the first blue light 24 into a first converted light 30. Specifically, the first luminescent material 28 may be configured to convert at least a portion of the first blue light 24, together with the unconverted first blue light 24, into a first converted light 30 including first green / yellow light and first red light that form a first white light 32 having a first correlated color temperature CCT1. Preferably, CCT1 ≤ 2500K (warm white light). Furthermore, the color rendering index (CRI) of the first white light 32 is preferably at least 80. The first luminescent material 28 may be a phosphor, and the first elongated encapsulant 26 may be made of, for example, silicone. A plurality of first blue LEDs 22, each comprising a first elongated encapsulant 26 and a first luminescent material 28, may be referred to as a first white light source.

[0029] The LED filament 14 further has an upper surface 34, in this case the upper surface 34 of the first elongated encapsulant 26. The upper surface 34 is on the opposite side of the bottom surface (second (support) surface 20b) of the LED filament 14. The upper surface 34 and the bottom surface 20b may be enclosed by end faces. As seen in Figure 1c, the upper surface 34 has an upper surface area TSA, and generally TSA = L × D.

[0030] The LED filament 10 further includes a second light source, which includes a string 36 of second blue LEDs 38 adapted to emit second blue light 40. The string 36 of second blue LEDs 38 here includes only second blue LEDs 38. The string of second blue LEDs is disposed on a light-transmitting substrate (not shown) either directly on the top surface 34 of the LED filament 14 or on the top surface 34 of the LED filament 14, such that the light output surfaces 42 of the second blue LEDs 38 face away from the LED filament 14. That is, during operation, the second blue light 40 is emitted away from the first encapsulant 26 containing the luminescent material 28. Each light output surface 42 may be the top surface of the blue LED 38, while the bottom surface 44 opposite to the blue LED 38 faces the top surface 34 (of the first elongated encapsulant 26) of the LED filament 14 and may be mounted therein. Therefore, the second blue LED 38 is sometimes referred to as a top-emitting second blue LED 38. The string 36 of the second blue LED 38 is preferably positioned at the longitudinal centerline of the top surface 34 of the LED filament 14, as seen in Figure 1c. That is, the first and second blue LEDs 22 and 42 can be arranged stacked in the same direction. The number of second blue LEDs 38 may be, for example, at least 10 or at least 20.

[0031] By having a string 36 of second blue LEDs 38 disposed above / in front of the first elongated encapsulant 26 / first luminescent material 28, and emitting second blue LED light 40 away from the first elongated encapsulant 26 / first luminescent material 28 while in operation, optical crosstalk (i.e., the action of the operating blue LED 38 stimulating the phosphor converter / luminescent material 28 of the LED filament, which then causes the phosphor converter / luminescent material 28 to emit light of a different color) is reduced / eliminated, and therefore pure blue light can be supplied.

[0032] The string 36 of the second blue LED 38 may have a string area SA. The string area SA may be the sum of the area of ​​the light output surface 42 of the second blue LED 38 and the area of ​​the associated electrical track. The (approximate) string area SA is shown by diagonal stripes in Figure 1c. Preferably, SA < 0.2 TSA, thereby the second blue LED 38 does not block an excess amount of the first blue light 24 and / or the first converted light 30. The electrical track may include, for example, copper wire / track. Furthermore, the string 36 of the second blue LED 38 may have an ultra-narrow pitch LED pitch P of less than 1000 μm.

[0033] The LED filament 10 may further have a second elongated encapsulant 46 that covers the string 36 of the second blue LED 38. The second elongated encapsulant 46 does not contain luminescent material or light scattering material. The second elongated encapsulant 46 may be transparent, for example. The second elongated encapsulant 46 may be made of silicone, for example. The second elongated encapsulant 46 may have a dome-shaped cross-section with respect to its width D, as seen, for example, in Figure 1a. The dome-shaped cross-section may be uniform over substantially the entire length of the second elongated encapsulant 46.

[0034] The LED filament 10 may further include an electronic controller 48. The controller 48 is configured to individually control the emission of first blue light 24 from a plurality of first blue LEDs 22 and the emission of second blue light 40 from a string of second blue LEDs 38. Thus, during operation, the LED filament 10 in Figures 1a to 1c can selectively supply white light 32, blue light 40, or a combination thereof.

[0035] Figure 2a is a cross-sectional view of an LED filament 10 according to another embodiment. The LED filament 10 in Figure 2a is similar to the LED filament 10 in Figures 1a to 1c, but further comprises a plurality of red LEDs 50 adapted to emit red light 52 and a plurality of green LEDs 54 adapted to emit green light 56. The plurality of red LEDs 50 and the plurality of green LEDs 54 are arranged either directly on the upper surface 34 of the LED filament 14 or on a light-transmitting substrate (not shown) on the upper surface 34 of the LED filament 14, such that their light output surfaces 42' face away from the LED filament 14. The plurality of red LEDs 50 are arranged in a string on one side of the string 36 of the second blue LEDs 38, and the string of red LEDs 50 is parallel to the string 36 of the second blue LEDs 38. Multiple green LEDs 54 are arranged in a separate string on the other side of the string 36 of the second blue LEDs 38, and the string of green LEDs 54 is also parallel to the string 36 of the second blue LEDs 38. The number of red LEDs 50 may be, for example, at least 10 or at least 20. The number of green LEDs 54 may be, for example, at least 10 or at least 20. Multiple red LEDs 50 may be covered by an elongated encapsulant 58 similar to the second elongated encapsulant 46. Similarly, multiple green LEDs 54 may be covered by an elongated encapsulant 60 similar to the second elongated encapsulant 46. Alternatively, the second elongated encapsulant 46 may be extended to also cover the red LEDs 50 and green LEDs 54 (not shown in Figure 2a). The controller 48 may here be configured to individually control the emission of red light 52 from the multiple red LEDs 50 and the emission of green light 56 ​​from any multiple green LEDs 54. Therefore, during operation, the LED filament 10 in Figure 2a can selectively supply white light 32, blue light 40, red light 50, green light 54, or a combination thereof.

[0036] Figures 2b to 2c are cross-sectional views of the LED filament 10 according to other embodiments. The LED filament 10 in each of Figures 2b to 2c is similar to the LED filament 10 in Figure 2a, except that a plurality of red LEDs 50 and a plurality of green LEDs 54 are arranged on the support 16 of the LED filament 14. Specifically, the plurality of red LEDs 50 may be arranged and mounted on the first surface 20a of the support 16 (on one side of the plurality of first blue LEDs 22), and the plurality of green LEDs 54 may similarly be arranged and mounted on the first surface 20a of the support 16 (on the opposite side of the plurality of first blue LEDs 22). That is, the plurality of red LEDs 50 may be arranged in a string parallel to the linear array / string / single row of the first blue LEDs 22. Similarly, the plurality of green LEDs 54 may be arranged in another string parallel to the linear array / string / single row of the first blue LEDs 22.

[0037] In Figure 2b, the first elongated sealant 26 covers not only the multiple first blue LEDs 22, but also the multiple red LEDs 50, the multiple green LEDs 54, and at least a portion of the support 16. In Figure 2c, the first elongated sealant, represented by reference numeral 26', has an extended portion limited in the width direction and covers the multiple first blue LEDs 22 and only a portion of the support 16, but does not cover the multiple red LEDs 50 and the multiple green LEDs 54. The multiple red LEDs 50 and the multiple green LEDs 54 may not be covered, or may be provided with elongated sealants 58, 60 similar to those in Figure 2a (not shown in Figure 2c).

[0038] Figure 2d is a top view of the LED filament 10 according to another embodiment. The LED filament 10 in Figure 2d is similar to the LED filament 10 in Figure 2a, except that the string with the second blue LED 38 also includes a plurality of red LEDs 50 and a plurality of green LEDs 54. That is, the plurality of second blue LEDs 38, a plurality of red LEDs 50 and a plurality of green LEDs 54 are arranged in a single string / linear / row 36', preferably at the longitudinal centerline of the top surface 34 of the LED filament 14. The LEDs 38, 50, and 54 may be arranged in the string 36' in an alternating order of color (e.g., RGBRGB, i.e., (RGB)n, where n is preferably ≥ 5), but other arrangements such as batching may also be possible. Here, the second elongated encapsulant 46 may also cover the red LEDs 50 and green LEDs 54.

[0039] Figure 2e is a cross-sectional view of the LED filament 10 according to another embodiment. The LED filament 10 in Figure 2e is similar to the LED filament 10 in Figure 2a, except that the LED filament 14 further has a plurality of blue LEDs 62 adapted to emit a third blue light. The plurality of third blue LEDs 62 are arranged on a support 16. Specifically, the plurality of third blue LEDs 62 may be mounted on the first surface 20a of the support 16. Furthermore, the plurality of third blue LEDs 62 are preferably arranged in a linear array / string / single row. The string of third blue LEDs 62 may be arranged parallel to the aforementioned string of first blue LEDs 22. These strings may be mounted on both sides of the longitudinal centerline of the support 16, as shown in Figure 2e. The number of third blue LEDs 62 may be, for example, at least 10 or at least 20.

[0040] The LED filament 14 in Figure 2e further comprises a third elongated encapsulant 66 covering a plurality of third blue LEDs and a portion of the support 16. The third elongated encapsulant 66 has a second luminescent material 68 configured to convert at least a portion of the third blue light 64 into a second converted light 70. Specifically, the second luminescent material 68 may be configured to convert at least a portion of the third blue light 64, together with the unconverted third blue light 64, into a second converted light 70 including second green / yellow light and second red light, which forms a second white light 72 having a second correlated color temperature CCT2 different from the first correlated color temperature CCT1. Preferably, CCT2-CCT1 ≥ 500K, and more preferably, CCT2-CCT1 ≥ 1000K. Generally, CCT2 ≥ 3500K. Furthermore, the color rendering index (CRI) of the second white light 72 is preferably at least 80. The second luminescent material 68 may be a phosphor, and the second elongated encapsulant 66 may be made of, for example, silicone. Multiple third blue LEDs 62 comprising a third elongated encapsulant 66 and a second luminescent material 68 may be called a third white light source.

[0041] Each of the first elongated sealant 26 and the third elongated sealant 66 can cover approximately half of the support 16 when viewed from the width direction. Therefore, the first elongated sealant 26 and the third elongated sealant 66 can be parallel to each other (in the longitudinal direction of the LED filament 12 / LED filament 14). The upper surface 34 of the LED filament 14 can be formed here by the upper surfaces of the first elongated sealant 26 and the third elongated sealant 66. Furthermore, a string of second blue LEDs 38 can be arranged at the boundary 74 between the first elongated sealant 26 and the third elongated sealant 66 (on the upper surface 34). Multiple red LEDs 50 may be arranged on the first elongated sealant 26, and multiple green LEDs 54 may be arranged on the third elongated sealant 66. Alternatively, a single string of a second blue LED 38, a red LED 50, and a green LED 54 (as shown in Figure 2d) may be arranged at the boundary 74 (not shown).

[0042] The controller 48 may also be configured to individually control the emission of third blue light 64 from multiple third blue LEDs 62. Thus, during operation, the LED filament 10 in Figure 2e can selectively supply first white light 32, second white light 72, blue light 40, red light 50, green light 54, or a combination thereof. Furthermore, the second elongated encapsulant may be a common elongated encapsulant 46' that covers not only the string 36 of the second blue LEDs 38 but also multiple red LEDs 50 and any multiple green LEDs 54. The common elongated encapsulant 46' may simplify the manufacturing of the LED filament 10. Alternatively, the LED filament 10 in Figure 2e may have individual elongated encapsulants 46, 58, 60, for example, as shown in Figure 2a.

[0043] Figure 4 illustrates a lamp 102 according to an embodiment of the present invention. The lamp 102 comprises at least one LED filament 10, a controller 48, and an antenna 104 functionally coupled to the controller 48. The antenna 104 may be configured to receive user input from at least one user interface 106 and / or data from at least one sensor 108. The controller 54 may also be configured to control a plurality of first blue LEDs 22 and a plurality of second blue LEDs 38, as well as optional red LEDs 50, green LEDs 54, and third blue LEDs 62, based on user input from the user interface 106 and / or (detection) data from at least one sensor 108. The lamp 102, as well as the user interface 106 and / or sensor 108, may be referred to as a lighting system 100. The user interface 106 and / or sensor 108 may be located far from the lamp 102. The user interface 106 may be embodied, for example, in a mobile phone. At least one sensor 108 may include, for example, at least one of a camera, a light sensor, a presence sensor, and a proximity sensor.

[0044] The LED filaments 14 / LED filaments 10 are arranged in a coiled configuration here, but other configurations such as a linear configuration are also possible. The lamp 102 may further include an envelope 110 surrounding the LED filaments 14 / LED filaments 10, and a base or socket 112 for electrically and mechanically connecting the lamp 102 to an external socket (not shown). The lamp 102 may be, for example, a retrofit light bulb.

[0045] Those skilled in the art will see that the present invention is by no means limited to the preferred embodiments described above. On the contrary, many modifications and changes are possible within the scope of the appended claims.

[0046] Furthermore, a person skilled in the art will be able to understand and achieve modifications to the disclosed embodiments in the practice of the claimed invention by studying the drawings, specification and appended claims. In the claims, the word “has” does not exclude other elements or steps, and singular notation does not exclude plural. The mere fact that certain means are listed in different dependent claims does not mean that combinations of these means cannot be used to one's advantage.

Claims

1. It is an LED filament, support, A plurality of first blue LEDs adapted to emit first blue light, wherein the plurality of first blue LEDs are arranged on the support, A first elongated encapsulant covering the plurality of first blue LEDs and at least a portion of the support, the first elongated encapsulant having a first luminescent material configured to convert at least a portion of the first blue light into first converted light, the first elongated encapsulant having an upper surface, and An LED filament comprising a string of second blue LEDs adapted to emit second blue light, a string of second blue LEDs attached directly to the upper surface of the first elongated encapsulant, wherein the light output surface of the second blue LEDs faces away from the upper surface.

2. The LED filament according to claim 1, wherein the upper surface has an upper surface area TSA, and the string of the second blue LED has a string area SA, with SA < 0.4 TSA.

3. The LED filament according to claim 1 or 2, further comprising a controller configured to individually control the emission of the first blue light from the plurality of first blue LEDs and the emission of the second blue light from the string of second blue LEDs.

4. The LED filament according to claim 1 or 2, wherein the string of the second blue LED is disposed on a light-transmitting substrate directly on the upper surface of the first elongated encapsulant, or on the upper surface of the first elongated encapsulant.

5. The LED filament according to claim 1 or 2, wherein the string of the second blue LED is covered with a second elongated encapsulant that does not contain a luminescent material and a light scattering material.

6. The LED filament according to claim 1 or 2, wherein the string of the second blue LED has an LED pitch of less than 1000 μm.

7. The LED filament according to claim 1 or 2, further comprising a plurality of red LEDs adapted to emit red light, optionally further comprising a plurality of green LEDs adapted to emit green light, wherein the plurality of red LEDs and the optional plurality of green LEDs are arranged on the upper surface of the first elongated sealing material.

8. The LED filament according to claim 7, wherein the plurality of red LEDs and the optional plurality of green LEDs are arranged in at least one string of the LED filament.

9. The LED filament according to claim 7, wherein the string of the second blue LEDs includes only the second blue LED.

10. The LED filament according to claim 7, wherein the string of the second blue LEDs also includes the plurality of red LEDs and an optional plurality of green LEDs.

11. The LED filament according to claim 1 or 2, wherein the first luminescent material is configured to convert at least a portion of the first blue light, together with the first blue light emitted by the plurality of first blue LEDs that was not converted, into a first converted light including first green / yellow light and first red light that forms a first white light having a first correlated color temperature CCT1, and CCT1 ≤ 2500K.

12. The aforementioned LED filament A plurality of third blue LEDs adapted to emit third blue light, wherein the plurality of third blue LEDs are arranged on the support, and The LED filament according to claim 1 or 2, further comprising a third elongated encapsulant covering the plurality of third blue LEDs and at least a portion of the support, the third elongated encapsulant having a second luminescent material configured to convert at least a portion of the third blue light into second converted light.

13. The LED filament according to claim 12, wherein the string of the second blue LED is arranged at the boundary between the first elongated sealing material and the third elongated sealing material.

14. The LED filament according to claim 12, wherein the second luminescent material is configured to convert at least a portion of the third blue light, together with the third blue light emitted by the plurality of third blue LEDs that was not converted, into a second converted light including a second green / yellow light and a second red light that forms a second white light having a second correlated color temperature CCT2 higher than the first correlated color temperature, wherein CCT2 - CCT1 ≥ 500K, and the color rendering index of the first white light and the second white light is at least 80.

15. A lamp or lighting fixture including an LED filament according to claim 1 or 2, and an antenna functionally coupled to the controller of the LED filament, A lighting system having at least one user interface for supplying user input and / or at least one sensor for detecting data, A lighting system in which the controller is configured to control the plurality of first blue LEDs and the second blue LEDs based on the user input and / or the data.

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