WO2025202023A1

WO2025202023A1 - A led filament arrangement

Info

Publication number: WO2025202023A1
Application number: PCT/EP2025/057649
Authority: WO
Inventors: Ties Van Bommel; Erik Petrus Johannes MALLENS
Original assignee: Signify Holding BV
Current assignee: Signify Holding BV
Priority date: 2024-03-25
Filing date: 2025-03-20
Publication date: 2025-10-02
Anticipated expiration: 2026-09-25

Abstract

The invention relates to a LED filament arrangement (1; 100; 101; 102) with improved optical performance and/or improved functionality. The LED filament arrangement comprising a first LED filament component (2) for generating first LED filament component light (23), and a second LED filament component (3) for generating second LED filament component light (33). The first LED filament component (2) comprises (i) a plurality of first LEDs (21) for emitting first LED light, the plurality of first LEDs (21) being arranged on a first elongated carrier (91), and (ii) a first encapsulant (22) at least partially covering each of the plurality of first LEDs (21) and the first elongated carrier (91). The second LED filament component (3) comprises (i) a plurality of second LEDs (31) for emitting second LED light, the plurality of second LEDs (31) being arranged on the first elongated carrier (91), and (ii) a second encapsulant (32) at least partially covering each of the plurality of second LEDs (31) and the first elongated carrier (91). The first LED filament component light (23) is white light having a first color point with coordinates x1 and γ1, and a first correlated color temperature CCT1, and the second LED filament component light (33) is white light having a second color point with coordinates 2 and 2, and a second correlated color temperature CCT2, wherein [CCT2 −CCT1] ≤ 300 K, and γ2 − γ1 ≥ 0.03.

Description

A LED filament arrangement

FIELD OF THE INVENTION

The invention relates to a light emitting diode, LED, filament arrangement. The invention further relates to a lamp and a luminaire comprising such a LED filament arrangement.

As used herein, the term “green-yellow light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 500 to 590nm.

As used herein, the term “orange-red light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 590 to 660nm.

BACKGROUND OF THE INVENTION

A trend in lighting is LED filament lamps. An LED filament lamp is an LED lamp which is designed to resemble a traditional incandescent light bulb with a visible filament for aesthetic and light distribution purposes, but with the high efficiency of lightemitting diodes.

A LED filament is providing LED filament light and comprises a plurality of light emitting diodes (LEDs) arranged in a linear array. Preferably, the LED filament has a length L and a width W, wherein L > 5W. The LED filament may be arranged in a straight configuration or in a non-straight configuration such as for example a curved configuration, a 2D/3D spiral, or a helix. Preferably, the LEDs are arranged on an elongated carrier like for instance a carrier, that may be rigid (made from, e.g., a polymer, glass, quartz, metal, or sapphire) or flexible (e.g., made of a polymer or metal, e.g., a film or foil).

In case the elongated carrier comprises a first major surface and an opposite second major surface, the LEDs are arranged on at least one of these surfaces. The elongated carrier may be reflective or light transmissive, such as translucent and preferably transparent.

As used herein, the terms carrier and elongated carrier may be used interchangeably, such that the elongated carrier may also simply be denoted carrier.

The LED filament may comprise an encapsulant at least partially covering at least part of the plurality of LEDs. The encapsulant may also at least partially cover at least one of the first major surface and second major surface. The encapsulant may be a polymer material which may be flexible such as for example a silicone. Further, the LEDs may be arranged for emitting LED light, e.g., of different colors or spectrums. The encapsulant may comprise a luminescent material that is configured to convert at least a part of the LED light into converted light. The luminescent material may be a phosphor such as an inorganic phosphor and/or quantum dots or rods (QDs). The term ‘luminescent material’ may also refer to a combination of two or more luminescent materials.

The LED filament may comprise multiple sub-filaments.

WO 2022/207603 Al discloses an LED filament device comprising a first LED filament side, a second LED filament side, and a plurality of sources of light. First sources of light are configured to generate first white light having a first correlated color temperature CCT1, and the first sources of light are associated to the first filament side. Second sources of light are configured to generate second white light having a second correlated color temperature CCT2, and the second sources of light are associated to the first filament side. The first and second correlated color temperature may be chosen such that CCT2-CCT1 > 500 K. Third sources of light are configured to generate blue third light, and the third sources of light are associated to the second filament side. Fourth sources of light are configured to generate green fourth light, and the fourth sources of light are associated to the second filament side. Fifth sources of light are configured to generate red fifth light, and the fifth sources of light are associated to the second filament side.

It is desired to improve the optical performance and/or appearance of LED filaments.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome this problem, and to provide a LED filament arrangement with an improved optical performance and/or functionality.

According to a first aspect of the invention, this and other objects are achieved by means of a LED filament arrangement for generating LED filament arrangement light (in other words, it is configured to generate, in operation, LED filament arrangement light)

The LED filament arrangement comprises a first LED filament component for generating first LED filament component light, and a second LED filament component for generating second LED filament component light. The first LED filament component comprises a plurality of first LEDs, such as an array of a plurality of first LEDs. The plurality of first LEDs is for emitting first LED light, and it is arranged on a first elongated carrier.

The first LED filament component further comprises a first encapsulant. At least a part of the plurality of first LEDs is covered by the first encapsulant. Also, at least a part of the first elongated carrier is covered by the first encapsulant. In other words, the first encapsulant at least partially covers the plurality of first LEDs and at least partially covers the first elongated carrier.

The first encapsulant comprises a first luminescent material for converting at least a part of the first LED light into first luminescent material light. The first LED filament component light generated by the first LED filament component comprises the first luminescent material light, or it comprises a combination of the first luminescent material light and part of the first LED light.

The second LED filament component comprises a plurality of second LEDs, such as an array of a plurality of second LEDs. The plurality of second LEDs is for emitting second LED light, and it is arranged on the first elongated carrier.

The second LED filament component further comprises a second encapsulant. At least a part of the plurality of second LEDs is covered by the second encapsulant. Also, at least a part of the first elongated carrier is covered by the second encapsulant. In other words, the second encapsulant at least partially covers the plurality of second LEDs and at least partially covers the first elongated carrier.

The second encapsulant comprises a second luminescent material for converting at least a part of the second LED light into second luminescent material light. The second LED filament component light generated by the second LED filament component comprises the second luminescent material light, or it comprises a combination of the second luminescent material light and part of the second LED light.

The first LED filament component light generated by the first LED filament component is white light having a first color point with coordinates xl and yl, and with a first correlated color temperature CCT1.

The second LED filament component light generated by the second LED filament component is white light having a second color point with coordinates x2 and y2, and with a second correlated color temperature CCT2.

The coordinates of the first and second color points refer to coordinates in the CIE 1931 RGB color space. The absolute value of the difference between the second correlated color temperature CCT2 and the first correlated color temperature CCT1 is not more than 300 K. In other words, | CCT2 - CCT11 < 300 K.

Furthermore, the difference between the y-coordinates of the second and first color points is at least 0.03. In other words, y2 — yl > 0.03.

The above LED filament arrangement, having a combination of two LED filament components, has at least one of an improved optical performance and an improved functionality.

This combination of two LED filaments components allows to have a trade-off between efficiency and light quality.

In addition, this combination of two LED filament components allows to provide different light recipes which can be used in different applications and/or situations such as increased white rendering and color saturation.

The plurality of first LEDs and the plurality of second LEDs may be arranged alternatingly on the first elongated carrier along a length direction of the first elongated carrier. Alternatively, the plurality of first LEDs and the plurality of second LEDs may be arranged side-by-side on the first elongated carrier along a length direction of the first elongated carrier.

The first LED filament component light has a first luminous flux (LF1), and the second LED filament component light has second luminous flux (LF2). The LED filament arrangement may further comprise a controller configured to control a ratio of the first luminous flux (LF1) of the first LED filament component light and the second luminous flux (LF2) of the second LED filament component light. In other words, the controller is configured to control LF1/LF2.

Thereby, the efficiency and the color rendering index (CRI) of the LED filament arrangement may be adjusted while keeping the correlated color temperatures constant, or almost constant.

The controller may be configured to control the ratio of the first luminous flux (LF1) of the first LED filament component light and the second luminous flux (LF2) of the second LED filament component light such that, in a first operational mode, the ratio is not more than 0.5, and in a second operational mode, it is at least 2. In other words, the controller is configured to control LF1/LF2 such that, in a first operational mode, LF1/LF2 < 0.5, and in a second operational mode, LF1/LF2 > 2. Thereby, the efficiency and the color rendering index (CRI) of the LED filament arrangement may be adjusted further while still keeping the correlated color temperatures constant or almost constant.

In the LED filament arrangement, the absolute value of the difference between the second correlated color temperature CCT2 and the first correlated color temperature CCT1 may be not more than 200 K. In other words, \CCT2 — CCT1\ < 200 K.

Additionally, the difference between the y-coordinates of the second and first color points may be at least 0.05. In other words, y2 — yl > 0.05.

The obtained effect is a further improved variation in, e.g., efficiency versus light quality, e.g., color rendering index (CRI) and/or R9 value (the latter being a value that represents how accurate a light source will reproduce strong red colors).

The first LED filament component light is white light having a first color point with coordinates xl and yl.

The first color point may be located above the black body locus (BBL). The obtained effect is a higher efficiency.

The first color point may be located at least 7 SDCM above the BBL, such as at least 10 SDCM above the BBL, or at least 12 SDCM above the BBL. Thereby, the efficiency obtained may be even higher.

The second LED filament component light is white light having a second color point with coordinates x2 and y2.

The second color point may be located below the black body locus (BBL). The obtained effect is a higher CRI and/or R9 value.

The second color point may be located at least 7 SDCM below the BBL, such at least 10 SDCM below the BBL, or at least 12 SDCM below the BBL. Thereby, an even higher CRI and/or R9 value may be obtained.

The first luminescent material may comprise a first green-yellow phosphor and a first orange-red phosphor, and the second luminescent material may comprise a second green-yellow phosphor and a second orange-red phosphor. Herein, one or more of the following may apply: (i) the first green-yellow phosphor is different from the second greenyellow phosphor, and (ii) the first orange-red phosphor is different from the second orange- red phosphor.

Thereby, when viewing the LED filament arrangement in a direct view, no spottiness is perceived by the viewer. In addition, the light quality is improved as the spectral distribution is more continuous. The first and second green-yellow phosphor are arranged to convert LED light into green-yellow (phosphor) light. The first and second orange-red phosphor are arranged to convert LED light and/or green-yellow (phosphor) light into orange-red (phosphor) light.

The first orange-red phosphor may comprise one or more of an oxynitride phosphor and a nitride phosphor.

Additionally or alternatively, the second orange-red phosphor may comprise a phosphor of the type M’_xM2-2xAX6 doped with a tetravalent manganese cation, wherein M’ is a cation of an alkaline earth metal, M comprises a cation of an alkali metal, x is selected from the range of 0 to 1, wherein A is a tetravalent cation, for instance comprising one or more of silicon and titanium, wherein X is a monovalent anion, at least comprising fluorine.

The phosphors of the above type can be referred to as ’’narrow-band Mn activated (fluoride)” phosphors. Use of such phosphors result in a relatively high efficiency, while use of (oxy)nitride phosphors results in a relatively high CRI and/or R9 value.

The first LED light may be blue light having a first dominant peak wavelength

(21), and the second LED light may be blue light having a second dominant peak wavelength

(22), wherein |22 — 211 > 30 nm, and preferably 22 — 21 > 30 nm.

Thereby the effect of a relatively high spectral tunability is obtained.

For example, the first dominant peak wavelength 21 may be equal to or smaller than 440 nm, and the second dominant peak wavelength 22 may be equal to or longer than 470 nm.

The LED filament arrangement may further comprise a first LED filament comprising the first LED filament component and the second LED filament component, wherein the first encapsulant and the second encapsulant are arranged alternatingly along a length direction (LI) of the first LED filament. Hereby, a slim LED filament is obtained.

The LED filament may further comprise a first LED filament comprising the first LED filament component and the second LED filament component, wherein the first LED filament component and the second LED filament component are arranged next to each other or extending parallel to each other. Hereby, less fluctuations in color point along the length of the LED filament arrangement is obtained.

The LED filament arrangement may further comprise a third LED filament component for generating third LED filament component light.

The third LED filament component comprises a plurality of third LEDs, such as an array of a plurality of third LEDs. The plurality of third LEDs is for emitting third LED light, and it is arranged on a second elongated carrier The third LED filament component further comprises a third encapsulant. At least a part of the plurality of third LEDs is covered by the third encapsulant. Also, at least a part of the second elongated carrier is covered by the third encapsulant. In other words, the third encapsulant at least partially covers the plurality of third LEDs and at least partially covers the second elongated carrier.

The third encapsulant comprises a third luminescent material for converting at least a part of the third LED light into third luminescent material light. The third LED filament component light generated by the third LED filament component comprises the third luminescent material light, or it comprises a combination of the third luminescent material light and part of the third LED light.

The third LED filament component light is white light having a third color point with coordinates x3 and y3, and with a third correlated color temperature CCT3.

The absolute value of the difference between the third correlated color temperature CCT3 and the second correlated color temperature CCT2 is not more than 300 K. In other words, |CCT3 — CCT2\ < 300 K.

Furthermore, the absolute value of the difference between the y-coordinate of the third color point and each of the y-coordinates of the first and second color points is at least 0.03. In other words, |y3 — yl| > 0.03 and |y3 — y2| > 0.03.

The above LED filament arrangement, having a combination of three LED filament components, has at least one of a further improved optical performance and a further improved functionality.

This combination of three LED filament components allows to have an increased trade-off between efficiency and light quality.

In addition, this combination of three LED filament components allows to further provide different light recipes which can be used in different applications and/or situations such as increased white rendering and color saturation.

The first and second elongated carriers may be two separate carriers.

Alternatively, the first and second elongated carriers together form one elongated carrier, for instance by the first and second elongated carriers being formed in one piece. Hereby, a compact LED filament arrangement is provided.

When the LED filament arrangement comprises first, second, and third LED filament components, it may further comprise a second LED filament comprising the third LED filament component, wherein the third encapsulant is arranged along a length direction (L2) of the second LED filament. Hereby, a compact LED filament arrangement is provided, allowing more advanced spectral tuning.

The LED filament arrangement may further comprise a fourth LED filament component for generating fourth LED filament component light.

The fourth LED filament component comprises a plurality of fourth LEDs, such as an array of a plurality of fourth LEDs. The plurality of fourth LEDs is for emitting fourth LED light, and it is arranged on the second elongated carrier.

The fourth LED filament component further comprises a fourth encapsulant. At least a part of the plurality of fourth LEDs is covered by the fourth encapsulant. Also, at least a part of the second elongated carrier is covered by the fourth encapsulant. In other words, the fourth encapsulant at least partially covers the plurality of fourth LEDs and at least partially covers the second elongated carrier.

The fourth encapsulant comprises a fourth luminescent material for converting at least a part of the fourth LED light into fourth luminescent material light. The fourth LED filament component light comprises the fourth luminescent material light, or it comprises a combination of the fourth luminescent material light and part of the fourth LED light.

The fourth LED filament component light is white light having a fourth color point with coordinates x4 and y4, and with a fourth correlated color temperature CCT4.

The absolute value of the difference between the fourth correlated color temperature CCT4 and the third correlated color temperature CCT3 is not more than 300 K. In other words, \CCT4 — CCT3| < 300 K.

Furthermore, the absolute value of the difference between the y-coordinate of the fourth color point and each of the y-coordinates of the first, second, and third color points is at least 0.03. In other words, \y4 — yl| > 0.03, |y4 — y2| > 0.03, and |y4 — yl| > 0.03.

The above LED filament arrangement, having a combination of four LED filament components, has at least one of an even further improved optical performance and an even further improved functionality.

This combination of four LED filaments components allows to have a further increased trade-off between efficiency and light quality. In addition, this combination of four LED filament components allows to even further provide different light recipes which can be used in different applications and/or situations such as increased white rendering and color saturation. The plurality of third LEDs and the plurality of fourth LEDs may be arranged alternatingly on the second elongated carrier along a length direction of the first elongated carrier.

Alternatively, the plurality of third LEDs and the plurality of fourth LEDs may be arranged side-by-side on the second elongated carrier along a length direction of the second elongated carrier.

When the LED filament arrangement comprises first, second, third, and fourth LED filament components, it may further comprise a second LED filament comprising the third LED filament component and the fourth LED filament component, wherein the third encapsulant and the fourth encapsulant are arranged alternatingly along a length direction (L2) of the second LED filament. Hereby, a compact and slim LED filament arrangement is obtained.

The first LED filament component and the third LED filament component may be identical, and the second LED filament component and the fourth LED filament component may be identical.

Alternatively, the first LED filament component and the fourth LED filament component may be identical, and the second LED filament component and the third LED filament component may be identical.

Thereby, a LED filament arrangement providing LED filament arrangement light with an improved homogeneity and/or intensity is provided. Thereby, the performance of the LED filament arrangement is improved.

The first LED filament component, the second LED filament component, and, where provided, the third LED filament component and the fourth LED filament component, may be provided as separate LED filaments, and may for instance be arranged at a distance of at least 5 mm from each other.

Thereby, a LED filament arrangement capable of providing a variety of light effects is obtained, since the first, second, third and fourth LED filament component light becomes discernable from one another.

The invention further relates to a lighting device comprising a LED filament arrangement according to the invention.

The first LED filament component light has a first luminous flux (LF1), the second LED filament component light has second luminous flux (LF2), and the lighting device may further comprise a controller configured to control a ratio of the first luminous flux (LF1) of the first LED filament component light and the second luminous flux (LF2) of the second LED filament component light. In other words, the controller is configured to control LF1/LF2.

The obtained effect is that one can (gradually) change the light recipe and tune the efficiency versus light quality.

In case of addition of a third LED filament component for emitting third LED filament component light having a third luminous flux (LF3), and/or a fourth LED filament component for emitting fourth LED filament component light having a fourth luminous flux (LF4), the controller may further be configured to control a ratio of the third luminous flux (LF3) of the third LED filament component light and the fourth luminous flux (LF4) of the fourth LED filament component light. In other words, the controller is configured to control LF3/LF4.

In case of addition of a third LED filament component for emitting third LED filament component light having a third luminous flux (LF3), and/or a fourth LED filament component for emitting fourth LED filament component light having a fourth luminous flux (LF4), the controller may be configured to control the ratio of the third luminous flux (LF3) of the third LED filament component light and the fourth luminous flux (LF4) of the fourth LED filament component light such that, in a first operational mode, the ratio is not more than 0.5, and in a second operational mode, it is at least 2. In other words, the controller is configured to control LF3/LF4 such that, in a first operational mode, LF3/LF4 < 0.5, and in a second operational mode, LF3/LF4 > 2.

The LED filament arrangement may be part of a lighting device. An example of such a lighting device is a LED filament lamp.

The invention further relates to a LED filament lamp comprising a LED filament arrangement according to the invention.

The LED filament lamp may further comprise (i) a light transmissive envelope at least partially enclosing the LED filament arangement, and (ii) a base for electrically and mechanically connecting the LED filament lamp to a socket.

The invention further relates to a luminaire comprising a LED filament lamp according to the invention, or comprising a LED filament arrangement according to the invention.

It is noted that the invention relates to all possible combinations of features recited in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

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.

Fig. 1 A shows a top view of a light emitting diode, LED, filament arrangement according to the invention.

Fig. IB shows a cross-sectional side view of the section marked B seen in the direction of the arrow B’ in Fig. 1 A of the LED filament arrangement according to Fig. 1 A.

Fig. 2 shows a top view of another LED filament arrangement according to the invention.

Fig. 3 shows a top view of another LED filament arrangement according to the invention.

Fig. 4 shows a top view of another LED filament arrangement according to the invention.

Fig. 5 shows a color space diagram showing a line indicating the black body locus BBL.

Fig. 6 shows a close up of the area VI indicated in Fig. 5 and showing correlated color temperatures, CCT, for a LED filament arrangement according to the invention.

Fig. 7 shows a further close up of the area VII indicated in Fig. 6 and showing correlated color temperatures, CCT, for a LED filament arrangement according to the invention.

Fig. 8 shows a schematical side view of a lamp comprising a LED filament according to the invention.

Fig. 9 shows a schematical side view of a luminaire comprising a lamp and a LED filament according to the invention.

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.

DETAILED DESCRIPTION OF THE EMBODIMENTS

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.

Fig. 1 A shows a top view of a light emitting diode, LED, filament arrangement 1 according to the invention, and Fig. IB shows a cross-sectional side view of the section marked B as seen in the direction of the arrow B’ in Fig. 1 A of the LED filament arrangement 1.

Generally, and irrespective of the embodiment, the LED filament arrangement 1 comprises a first LED filament component 2 configured to, in operation, generate first LED filament component light 23, and a second LED filament component 3 configured to, in operation, generate second LED filament component light 33.

The first LED filament component 2 comprises an array of a plurality of first LEDs 21. The array of a plurality of first LEDs 21 is configured to, in operation, emit first LED light. The first LED light may be blue light having a first dominant peak wavelength, XL The array of the plurality of first LEDs 21 is arranged on a first elongated carrier 91.

The first LED filament component 2 further comprises a first encapsulant 22. The first encapsulant 22 covers the plurality of first LEDs 21 at least partially. The first encapsulant 22 further covers the first elongated carrier 91 partially. The first encapsulant 22 comprises a first luminescent material 24. The first luminescent material 24 is configured to convert at least a part of the first LED light into first luminescent material light.

The first luminescent material 24 comprises a first green-yellow phosphor and a first orange-red phosphor. The first orange-red phosphor comprises one or more of an oxynitride phosphor and a nitride phosphor.

The first LED filament component light 23 comprises the first luminescent material light. Alternatively, the first LED filament component light 23 comprises a combination of the first luminescent material light and part of the first LED light.

The second LED filament component 3 comprises an array of a plurality of second LEDs 31. The array of a plurality of second LEDs 31 is configured to, in operation, emit second LED light. The second LED light may be blue light having a second dominant peak wavelength, X2. The first and second dominant wavelength may be chosen such that I X2-X1 I > 30 nm, and preferably X2-X1 > 30 nm. The array of the plurality of second LEDs 31 is arranged on the first elongated carrier 91.

Referring specifically to Fig. IB, the first elongated carrier 91 comprises a first major surface 93 and a second major surface 94. The array of the plurality of first LEDs 21 and the array of the plurality of second LEDs 31 are arranged on the same major surface, in the embodiment shown the first major surface 93. In the embodiment shown, the array of the plurality of first LEDs 21 and the array of the plurality of second LEDs 31 are further arranged altematingly along a length direction LC of the first elongated carrier 91.

The second LED filament component 3 further comprises a second encapsulant 32. The second encapsulant 32 covers the plurality of second LEDs 31 at least partially. The second encapsulant 32 further covers the first elongated carrier 91 partially. The second encapsulant 32 comprises a second luminescent material 34. The second luminescent material 34 is configured to convert at least a part of the second LED light into second luminescent material light.

The second luminescent material 34 may comprise a second green-yellow phosphor and a second orange-red phosphor. The first green-yellow phosphor may be different from the second green-yellow phosphor. Alternatively, or additionally, the first orange-red phosphor is different from the second orange-red phosphor. The second orange- red phosphor may comprise a phosphor of the type M’_xM2-2xAX6 doped with a tetravalent manganese cation, wherein M’ is a cation of an alkaline earth metal, M comprises a cation of an alkali metal, and x is selected from the range of 0-1, wherein A is a tetravalent cation, for instance comprising one or more of silicon and titanium, wherein X is a monovalent anion, at least comprising fluorine. Examples of preferred phosphors which belong to the above class of phosphors are IGSiFr,: Mn⁴⁺, K^GeFe: Mn⁴⁺, and K^TiFe: Mn⁴⁺.

The second LED filament component light 33 comprises the second luminescent material light. Alternatively, second LED filament component light 33 comprises a combination of the second luminescent material light and part of the second LED light.

The first LED filament component light 23 is white light having a first color point with coordinates (xl, yl) and a first correlated color temperature, CCT, (CCT1). The second LED filament component light 33 is white light having a second color point with coordinates (x2, y2) and a second CCT (CCT2). CCT1, CCT2 and the coordinates of the first and second color point are chosen such that I CCT2-CCT1 I < 300 K and y2-yl > 0.03. Alternatively, CCT1, CCT2 and the coordinates of the first and second color point are chosen such that I CCT2-CCT1 I < 200 K and y2-yl > 0.05.

The LED filament 1 arrangement may further comprise a controller 6. The first LED filament component light 23 further has a first luminous flux, LF1. The second LED filament component light 33 further has second luminous flux, LF2. The controller 6 may be configured to control the ratio LF1/LF2 of the first luminous flux LF1 of the first LED filament component light 23 with respect to the second luminous flux LF2 of the second LED filament component light 33. For instance, the controller 6 may be configured to control the ratio LF1/LF1 such that in a first operational mode LF1/LF2 < 0.5 and in a second operational mode LF1/LF2 > 2. The controller 6 may also be configured to control other parameters of the first LED filament component light 23 and the second LED filament component light 33.

The first color point (xl, yl) may be located above the black body locus, BBL. Alternatively, or additionally, the second color point (x2, y2) may be located below the black body locus, BBL.

Furthermore, the LED filament arrangement 1 comprises a first LED filament 7. The first LED filament 7 comprises the first LED filament component 2 and the second LED filament component 3. The first encapsulant 22 and the second encapsulant 32 are arranged alternatingly along a length direction, LI of the first LED filament 7 as shown in Fig. 1 A. Likewise, the plurality of first LEDs 21 and the plurality of second LEDs 31 are arranged alternatingly along a length direction, LI of the first LED filament 7 as shown in Fig. 1A.

Fig. 2 shows another LED filament arrangement 100 according to the invention. The LED filament arrangement 100 differs from the LED filament arrangement 1 described above with reference to Figs. 1 A and IB in virtue of the following features.

The first LED filament component 2 and the second LED filament component 3 are arranged on the LED filament 7 such that the first encapsulant 22 and the second encapsulant 32 are arranged extending next to each other or parallel to one another as seen in the length direction, LI, of the first LED filament 7. Likewise, the plurality of first LEDs 21 and the plurality of second LEDs 31 are arranged extending next to each other or parallel to one another as seen in the length direction, LI, of the first LED filament 7.

Fig. 3 shows another LED filament arrangement 101 according to the invention. The LED filament arrangement 101 differs from the LED filament arrangements 1 and 100 described above with reference to Figs. 1 A, IB and 2 in virtue of the following features.

In addition to a first and second LED filament component 2 and 3, the LED filament arrangement 101 comprises a third LED filament component 4. The third LED filament component 4 is configured to, in operation, generate third LED filament component light 43. The third LED filament component 4 generally comprises an array of a plurality of third LEDs 41 and a third encapsulant 42.

The array of a plurality of third LEDs 41 is configured to, in operation, emit third LED light. The array of the plurality of first LEDs 41 is arranged on a second elongated carrier 92.

The third encapsulant 42 covers the plurality of third LEDs at least partially. The third encapsulant 42 further covers the second elongated carrier 92 at least partially. The third encapsulant 42 comprises a third luminescent material 44. The third luminescent material 44 is configured to convert at least a part of the third LED light into third luminescent material light.

The third luminescent material 44 may for instance comprise a third greenyellow phosphor and a third orange-red phosphor. The third orange-red phosphor may comprise one or more of an oxynitride phosphor and a nitride phosphor.

The third LED filament component light 43 comprises the third luminescent material light. Alternatively, the third LED filament component light 43 comprises a combination of the third luminescent material light and part of the third LED light. The third LED filament component light 43 is white light having a third color point with coordinates (x3, y3) and a third CCT (CCT3). CCT2, CCT3 and the coordinates of the first, second and third color point are chosen such that I CCT3-CCT2 I < 300 K and I y3-yl I > 0.03 and I y3- y2 I > 0.03.

The LED filament arrangement 101 further comprises a first LED filament 7 and a second LED filament 8. The first LED filament 7 is identical to the first LED filament described above with reference to Figs. 1 A and IB. The third LED filament component 4 is arranged on the second LED filament 8. The first LED filament 7 and the second LED filament 8 are arranged next to each other and extending parallel to one another as seen in the length direction, LI, of the first LED filament 7 and in the length direction, L2, of the second LED filament 8.

Fig. 4 shows another LED filament arrangement 102 according to the invention. The LED filament arrangement 102 differs from the LED filament arrangement 101 described above with reference to Fig. 3 in virtue of the following features.

In addition to a first, second and third LED filament component 2, 3 and 4, the LED filament arrangement 102 comprises a fourth LED filament component 5. The fourth LED filament component 5 is configured to, in operation, generate fourth LED filament component light 53. The fourth LED filament component 5 generally comprises an array of a plurality of fourth LEDs 51 and a fourth encapsulant 52.

The array of a plurality of fourth LEDs 51 is configured to, in operation, emit fourth LED light. The array of the plurality of fourth LEDs 51 is arranged on the second elongated carrier 92. The array of the plurality of fourth LEDs 51 and the array of the plurality of third LEDs 51 are arranged on the same major surface of the second elongated carrier 92.

The fourth encapsulant 52 covers the plurality of fourth LEDs at least partially. The fourth encapsulant 52 further covers the second elongated carrier 92 at least partially. The fourth encapsulant 52 comprises a fourth luminescent material 54. The fourth luminescent material 54 is configured to convert at least a part of the fourth LED light into fourth luminescent material light.

The fourth luminescent material 54 may comprise a second green-yellow phosphor and a second orange-red phosphor. The third green-yellow phosphor may be different from the fourth green-yellow phosphor. Alternatively, or additionally, the third orange-red phosphor is different from the fourth orange-red phosphor. The fourth orange-red phosphor may for instance comprise a phosphor of the type M’_xM2-2xAX6 doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises an alkaline cation, and x is selected from the range of 0-1, wherein A comprises a tetravalent cation, for instance comprising one or more of silicon and titanium, wherein X comprises a monovalent anion, at least comprising fluorine.

The fourth LED filament component light 53 comprises the fourth luminescent material light. Alternatively, the fourth LED filament component light 53 comprises a combination of the fourth luminescent material light and part of the fourth LED light. The fourth LED filament component light 53 is white light having a fourth color point with coordinates (x4, y4) and a fourth CCT (CCT4). CCT3, CCT4 and the coordinates of the first, second, third and fourth color points are chosen such that I CCT4-CCT3 I < 300 K and I y4- yl I > 0.03 and I y4-y2 I > 0.03 and I y4-y3 I > 0.03.

The LED filament arrangement 102 comprises a first LED filament 7 and a second LED filament 8. The first LED filament 7 is identical to the first LED filament described above with reference to Figs. 1 A and IB. The third LED filament component 4 and the fourth LED filament component 5 are arranged on the second LED filament 8. The third encapsulant 42 and the fourth encapsulant 52 are arranged altematingly along a length direction L2 of the second LED filament 8. Likewise, the plurality of third LEDs 41 and the plurality of fourth LEDs 51 are arranged altematingly along the length direction, L2, of the second LED filament 8.

Alternatively, the third encapsulant 42 and the fourth encapsulant 52 may be arranged next to or parallel to one another along a length direction L2 of the second LED filament 8. Likewise, the plurality of third LEDs 41 and the plurality of fourth LEDs 51 may be arranged next to or parallel to one another along the length direction, L2, of the second LED filament 8.

The first LED filament 7 and the second LED filament 8 are arranged next to each other and extending parallel to one another as seen in the length direction, LI, of the first LED filament 7 and in the length direction, L2, of the second LED filament 8.

The first LED filament component 2 and the third LED filament component 4 may be identical, and the second LED filament component 3 and the fourth LED filament component 5 may be identical. Alternatively, the first LED filament component 2 and the fourth LED filament component 5 may be identical, and the second LED filament component 3 and the third LED filament component 4 may be identical.

For any of the above embodiments it is furthermore feasible that the first LED filament component 2, the second LED filament component 3, if provided the third LED filament component 4 and if provided the fourth LED filament component 5, may be separate LED filaments, and for instance may be arranged in a distance from one another, such as a distance of at least 5 mm.

Reference is now made to Figs. 5 to 7. Fig. 5 shows a color space diagram showing a line indicating the black body locus BBL. Fig. 6 shows a close up of the area VI indicated in Fig. 5 and showing correlated color temperatures, CCT1 and CCT2, for a LED filament arrangement 1, 100, 101, 102 according to the invention. Fig. 7 shows a further close up of the area VII indicated in Fig. 6 and showing correlated color temperatures, CCT1 and CCT2, for a LED filament arrangement 1, 100, 101, 102 according to the invention.

As may be seen especially from Fig. 7, the correlated color temperatures, CCT1 and CCT2 are arranged on opposite sides of the black body locus, BBL, and within 300 K of one another. In a similar way, CCT2 and CCT3 are arranged within 300 K of one another, and may further optionally be arranged on opposite sides of the BBL. In a similar way, CCT3 and CCT4 are arranged within 300 K of one another, and may further optionally be arranged on opposite sides of the BBL.

Fig. 8 shows an exemplary lamp 300 comprising a LED filament 1, 100, 101, 102 according to any embodiment of the invention. In the embodiment shown, the LED filament 1, 100, 101, 102 comprises a substantially straight LED filament. The LED filament of such a lamp may in other embodiments be a LED filament with another shape, such as, but not limited to, spiral-shaped, helix-shaped, meandering, twisted, flat and combinations thereof.

The lamp 300 further comprises a driver or controller 305 configured for controlling the plurality of LEDs 4 of the LED filament 1, 100, 101, 102. The controller 305 is configured to power the plurality of LEDs 4 via electrical circuitry (not visible on the figures) of the LED filament 1, 100, 101, 102. The LED filament 1, 100, 101, 102 may also comprise a controller 6, which may or may not be separate from the controller 305. In other words, the controller 305 and the controller 6 of the LED filament 1 may be integrated into one and the same driver or controller, or they may be mutually separate units.

The lamp 300 further comprises an envelope 301 at least partially enveloping the at least one LED filament 1, 100, 101, 102. The lamp 300 further comprises a cap 303. As shown in Fig. 8, the controller 305 is arranged within the envelope 301. When comprising a cap 303, the controller 305 may also be arranged inside the cap 303 such that it is hidden from view. The lamp 300 further comprises threading 302 for connection to a socket, and a terminal 304 for connection to a source of electrical energy.

The envelope 301 of the lamp 300 may further and optionally be provided with a coating (not shown), such as a reflective coating, covering at least a part of the envelope 301.

Turning finally to Fig. 9, an exemplary light emitting device or luminaire in the form of a pendant 400 is shown. The pendant 400 comprises a LED filament 1, 100, 101, 102 according to any embodiment of the invention. The LED filament 1, 100, 101, 102 is as shown in Fig. 9 provided within a lamp 300 in the form of a light bulb. The LED filament 1, 100, 101, 102 as shown in Fig. 9 comprises a substantially straight LED filament.

As is also mentioned above, the light bulb further comprises a transparent envelope (cf. transparent envelope 301 of lamp 300) at least partially enveloping the at least one LED filament 1, 100. The transparent envelope may be shaped in any feasible shape, for example such as to resemble the shape of any one of a standard light bulb, a globe light bulb, a candlelight bulb, a customized light bulb and even a spiral light bulb. The transparent envelope may comprise a luminescent material. The transparent envelope may be a glass envelope.

The pendant 400 further comprises a socket 401 for connecting the lamp 300, and thereby the LED filament 1, 100, 101, 102, to the pendant 400. The socket 401 is adapted to cooperate with the base 303 of the lamp 300. The socket 401 may comprise a threading adapted to cooperate with the threading 302 of the lamp 300. The socket 401 may comprise a terminal adapted to cooperate with the terminal 304 of the lamp 300. The pendant 400 further comprises a reflector or screen 403.

The pendant 400 may further comprise a driver 402 configured for controlling the LED filament 1, 100, 101, 102. The driver 402 may or may not be the same unit as the controller 305 described above. In other words, the driver 402 and the controller 305 may be integrated into one and the same driver or controller, or they may be mutually separate units. Alternatively, or additionally, the LED filament 1, 100, 101, 102 may also comprise a controller 6, which may or may not be separate from one or both of the driver 402 and the controller 305.

As shown in Fig. 9, the driver 402 is arranged on a reflector or screen 403 of the pendant 400. The driver may also be arranged within or incorporated into the reflector or screen 403. The pendant 400 further comprises an electrical wiring 404 for connection to a source of electricity, such as a mains.

It is noted that the pendant 400 shown in Fig. 9 is only one example of a luminaire according to the invention. Any suitable type of luminaire may be envisaged, such as but not limited to, a standing luminaire, a wall hung luminaire, a chandelier, a reading luminaire, an outdoor luminaire, and a table luminaire.

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.

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 arrangement (1; 100; 101; 102) comprising a first LED filament component (2) for generating first LED filament component light (23), and a second LED filament component (3) for generating second LED filament component light (33), wherein the first LED filament component (2) comprises: a plurality of first LEDs (21) for emitting first LED light, the plurality of first LEDs (21) being arranged on a first elongated carrier (91), and a first encapsulant (22) at least partially covering the plurality of first LEDs (21) and at least partially covering the first elongated carrier (91), the first encapsulant (22) comprising a first luminescent material (24) for converting at least a part of the first LED light into first luminescent material light, the first LED filament component light (23) comprising the first luminescent material light or a combination of the first luminescent material light and part of the first LED light, wherein the second LED filament component (3) comprises: a plurality of second LEDs (31) for emitting second LED light, the plurality of second LEDs (31) being arranged on the first elongated carrier (91), and a second encapsulant (32) at least partially covering the plurality of second LEDs (31) and at least partially covering the first elongated carrier (91), the second encapsulant (32) comprising a second luminescent material (34) for converting at least a part of the second LED light into second luminescent material light, the second LED filament component light (33) comprising the second luminescent material light or a combination of the second luminescent material light and part of the second LED light, wherein the first LED filament component light (23) is white light having a first color point with coordinates xl and yl, and a first correlated color temperature CCT1, wherein the second LED filament component light (33) is white light having a second color point with coordinates x2 and y2, and a second correlated color temperature CCT2, and wherein \CCT2 - CCT1\ < 300 K and y2 - yl > 0.03.

2. The LED filament arrangement (1; 100; 101; 102) according claim 1, wherein

\CCT2 — CCT1\ < 200 K and y2 - yl > 0.05.

3. The LED filament arrangement (1; 100; 101; 102) according to any one of the preceding claims, wherein one or more of the following applies: the first color point is located above the black body locus, and the second color point is located below the black body locus.

4. The LED filament arrangement (1; 100; 101; 102) according to any one of the preceding claims, wherein the first luminescent material (24) comprises a first green-yellow phosphor and a first orange-red phosphor, wherein the second luminescent material (34) comprises a second green-yellow phosphor and a second orange-red phosphor, and wherein one or more of the following applies: the first green-yellow phosphor is different from the second green-yellow phosphor, and the first orange-red phosphor is different from the second orange-red phosphor.

5. The LED filament arrangement (1; 100; 101; 102) according to claim 4, wherein the first orange-red phosphor comprises one or more of an oxynitride phosphor and a nitride phosphor, and wherein the second orange-red phosphor comprises a phosphor of the type M’_XM2-2XAX6 doped with a tetraval ent manganese cation, M’ being a cation of an alkaline earth metal, M comprising a cation of an alkali metal, x being selected from the range of 0 to 1, A being a tetraval ent cation, and X being a monovalent anion, at least comprising fluorine.

6. The LED filament arrangement (1; 100; 101; 102) according to any one of the preceding claims, wherein the first LED light is blue light having a first dominant peak wavelength 21, wherein the second LED light is blue light having a second dominant peak wavelength 22, and wherein 122 — 211 > 30 nm.

7. The LED filament arrangement (1; 100; 101; 102) according to any one of the preceding claims, wherein any one of the following applies: the LED filament arrangement (1; 100; 101; 102) comprises a first LED filament (7) comprising the first LED filament component (2) and the second LED filament component (3), wherein the first encapsulant (22) and the second encapsulant (32) are arranged altematingly along a length direction of the first LED filament (7), or the LED filament arrangement (1; 100; 101; 102) comprises a LED filament (7) comprising the first LED filament component (2) and the second LED filament component (3), wherein the first LED filament component (2) and the second LED filament component (3) are arranged next to each other or extending parallel to each other.

8. The LED filament arrangement (1; 100; 101; 102) according to any one of the preceding claims, further comprising a third LED filament component (4) for generating third LED filament component light (43), wherein the third LED filament component (4) comprises: a plurality of third LEDs (41) for emitting third LED light, the plurality of third LEDs (41) being arranged on a second elongated carrier (92), and a third encapsulant (42) at least partially covering the plurality of third LEDs

(41) and at least partially covering the second elongated carrier (92), the third encapsulant

(42) comprising a third luminescent material (44) for converting at least a part of the third LED light into third luminescent material light, the third LED filament component light (43) comprising the third luminescent material light or a combination of the third luminescent material light and part of the third LED light, wherein the third LED filament component light (43) is white light having a third color point with coordinates x3 and y3, and a third correlated color temperature CCT3, and wherein \CCT3 - CCT2\ < 300 K, |y3 - yl| > 0.03, and |y3 - y2| > 0.03.

9. The LED filament arrangement (1; 100; 101; 102) according to claim 8, further comprising a fourth LED filament component (5) for generating fourth LED filament component light (52), wherein the fourth LED filament component (5) comprises: a plurality of fourth LEDs (51) for emitting fourth LED light, the plurality of fourth LEDs (51) being arranged on the second elongated carrier (92), and a fourth encapsulant (52) at least partially covering the plurality of fourth LEDs (51) and at least partially covering the second elongated carrier (92), the fourth encapsulant (52) comprising a fourth luminescent material (54) for converting at least a part of the fourth LED light into fourth luminescent material light, the fourth LED filament component light (53) comprising the fourth luminescent material light or a combination of the fourth luminescent material light and part of the fourth LED light, wherein the fourth LED filament component light (53) is white light having a fourth color point with coordinates x4 and y4, and a fourth correlated color temperature CCT4, wherein the plurality of third LEDs (41) at least partially covered by the third encapsulant (42), and the plurality of fourth LEDs (51) at least partially covered by the fourth encapsulant (52) are arranged altematingly along a length direction of the second LED filament (8), and wherein \CCT4 - CCT3\ < 300 K, |y4 - yl| > 0.03, |y4 - y2| > 0.03, and |y4 — y3| > 0.03.

10. The LED filament arrangement (1; 100; 101; 102) according to claim 9, wherein any one of the following applies: the first LED filament component (2) and the third LED filament component

(4) are identical, and the second LED filament component (3) and the fourth LED filament component (5) are identical, or the first LED filament component (2) and the fourth LED filament component

(5) are identical, and the second LED filament component (3) and the third LED filament component (4) are identical.

11. The LED filament arrangement (1; 100; 101; 102) according to any one of the preceding claims, wherein the first LED filament component (2), the second LED filament component (3), and, where provided, the third LED filament component (4) and the fourth LED filament component (5), are separate LED filaments.

12. A lighting device comprising the LED filament arrangement (1; 100; 101; 102) according to any one of the preceding claims.

13. The lighting device according to claim 12, wherein the first LED filament component light (23) has a first luminous flux and the second LED filament component light (33) has a second luminous flux, and wherein the lighting device further comprises a controller (6) configured to control a ratio of the first luminous flux and the second luminous flux.

14. The lighting device according to claim 13, wherein the controller (6) is configured to control the ratio of the first luminous flux and the second luminous flux such that, in a first operational mode, the ratio of the first luminous flux and the second luminous flux is equal to or smaller than 0.5, and, in a second operational mode, the ratio of the first luminous flux and the second luminous flux is equal to or larger than 2. 15 The lighting device according to any one of claims 12 to 14, wherein the lighting device is a LED filament lamp (300).