Illumination device arranged to emit white light and led filament device

Abstract

A lighting device (100) and a light emitting diode (LED) filament device (500) are provided. The lighting device (100) and the LED filament device (500) are configured to emit white lighting device light (110) and LED filament light (505), respectively. The lighting device comprises a carrier (120), a plurality of first LEDs (130) arranged on the carrier, the plurality of first LEDs (130) being configured to emit first LED light (140), an encapsulation (150) comprising a first luminescent material (155), the first luminescent material comprising a first phosphor configured to at least partially convert the emitted first LED light into first converted light (160) comprising green light, the encapsulation (150) comprising a second luminescent material (156) comprising a second phosphor configured to at least partially convert the first converted light into second converted light (160) comprising green light. Wherein the emitted white lighting device light comprises green light and red light. The emitted white lighting device light has a correlated color temperature (CCT) in the range of 1500-2500 K, and wherein at most 2% of the white lighting device light in the visible wavelength range is in the wavelength range of less than 495 nm.

Description

Technical Field

[0001] This invention generally relates to lighting devices including light-emitting diodes (LEDs). More specifically, this invention relates to lighting devices arranged to emit white light and LED filament devices. Background Technology

[0002] The use of light-emitting diodes (LEDs) for lighting purposes continues to attract attention. Compared to incandescent lamps, fluorescent lamps, neon lamps, etc., LEDs offer many advantages, such as longer operating life, reduced power consumption, and improved efficiency related to the ratio of light energy to heat energy. In particular, LED filament lamps are highly preferred because they are very decorative.

[0003] Due to the advantages of using LEDs, interest in replacing conventional light sources with LEDs has rapidly increased in many lighting installations. It should be understood that this replacement, also known as retrofitting, is appreciated and desired by users who wish to have the aesthetics of incandescent bulbs. Light source replacement (retrofitting) is typically performed by removing (or replacing) conventional light sources from the luminaire (e.g., lamp holder) of the lighting installation and attaching LEDs, (or multiple) LED units, or (or multiple) LED devices to the luminaire. One of these concepts is based on the LED filament placed within the bulb, as the appearance of such lamps is highly favored due to their decorative appeal.

[0004] Lighting devices and lamps, including those using LEDs, are commercially available and emit no violet (i.e., 380nm-420nm) and / or blue (i.e., 420nm-495nm) light during operation. Such lighting devices and lamps can be used in applications to prevent sleep disruption in humans and to prevent negative impacts on animal behavior at night or during the night.

[0005] However, since there is no violet and / or blue light emitted from the lighting equipment and lamps during operation, the light may be perceived as unnatural and / or unattractive.

[0006] Therefore, one object of the present invention is to combine the advantageous characteristics of light emitted from LED lighting devices and / or LED lamps, which are free of violet and / or blue light, while still achieving natural and / or aesthetically pleasing light.

[0007] US 10697591 discloses a low-brightness LED lamp that produces light designed for reading, relaxation, and sleep at night. Low melatonin suppression input, balanced with high color rendering index (CRI) and warm correlated color temperature (CCT), produces light with reduced circadian rhythm / melatonin suppression input. The designed LED phosphor produces a spectrum with relatively low blue and green content. This balances high CRI with the preference for warm (low CCT) lighting at night. Summary of the Invention

[0008] It is of interest to combine the advantageous properties of LEDs in terms of energy efficiency, light distribution, and / or aesthetics with the properties of light that is free of violet and / or blue light, while still providing natural and / or aesthetically pleasing light emission.

[0009] This and other objectives are achieved by providing a lighting device and an LED filament having the features of the independent claims. Preferred embodiments are defined in the dependent claims.

[0010] Therefore, according to a first aspect of the invention, an illumination device configured to emit white illumination light is provided. The illumination device includes a carrier, a plurality of first LEDs disposed on the carrier, wherein the plurality of first LEDs are configured to emit first LED light comprising violet-blue light having a peak wavelength λ0 in the wavelength range of 380-495 nm, and an encapsulation at least partially surrounding the carrier and at least partially surrounding the plurality of first LEDs. The encapsulation includes a first luminescent material comprising a first phosphor, the first phosphor being configured to at least partially convert the emitted first LED light into first converted light, the first converted light comprising green light having a green peak wavelength λ1 in the wavelength range of 505-520 nm. The emitted white illumination light comprises green and red light having a peak wavelength λ2 in the wavelength range of 610-680 nm (or 610-660 nm). The emitted white illumination light has a correlated color temperature (CCT) in the range of 1500-2500K, and the first converted light has a spectral distribution with a full width at half maximum (FWHM) of ≤40nm, such that at most 2% of the emitted white illumination light is in the wavelength range below 495nm in the visible wavelength range.

[0011] According to a second aspect of the invention, an LED filament device configured to emit white LED filament light is provided. The LED filament device includes: at least one LED filament comprising an elongated carrier; at least one first linear array of a plurality of first LEDs disposed on the elongated carrier, wherein the plurality of first LEDs are configured to emit first LED light comprising violet-blue light having a peak wavelength λ0 in a wavelength range of 380-495 nm; and at least one elongated package at least partially surrounding the elongated carrier and at least partially surrounding the plurality of first LEDs. The at least one elongated package comprises a first luminescent material comprising a first phosphor, the first phosphor being configured to at least partially convert the emitted first LED light into first converted light comprising green light having a green peak wavelength λ1 in a wavelength range of 505-520 nm. The emitted white LED filament light comprises green and red light, with a peak wavelength λ2 in the wavelength range of 610-680 nm (or 610-660 nm). The emitted white LED filament light has a correlated color temperature (CCT) in the range of 1500-2500 K, and the first converted light has a spectral distribution with a full width at half maximum (FWHM) of ≤40 nm, such that at most 2% of the emitted white LED filament light in the visible wavelength range is in the wavelength range below 495 nm.

[0012] Therefore, an LED filament device is a lighting device comprising at least one LED filament, wherein the carrier is an elongated carrier, and a plurality of first LEDs are arranged on the elongated carrier in at least one first linear array.

[0013] Therefore, the present invention is based on the idea of ​​providing a lighting device and / or an LED filament device arranged to emit (extremely) warm white light, which is free of violet and / or blue light. Suppression of violet-blue light from the white light is achieved by a first LED light comprising (or even constituting, i.e., violet-blue light with a peak wavelength λ0 in the wavelength range of 380-495 nm), while at most 2% (or at most 1%, e.g., 0%) of the emitted white LED filament light in the visible wavelength range is in the wavelength range below 495 nm. Through features of the lighting device and LED filament device, including encapsulation, emission of green and red light, (low) CCT, and concentration of white light in a specific wavelength range, the lighting device and LED filament device combine the advantageous characteristics of LEDs in terms of energy efficiency, light distribution purpose, and / or aesthetics with the characteristics of light free of violet and / or blue light, while still providing natural and / or aesthetically pleasing light emission. It should be understood that lighting devices and LED filament devices share the same general inventive concept.

[0014] A lighting device and / or LED filament device configured to emit white light is provided. "White light" herein refers to visible light in the wavelength range of 400-700 nm. The lighting device includes a carrier and a plurality of first LEDs disposed on the carrier. In the case of the LED filament device, the at least one LED filament includes an elongated carrier and at least one first linear array of a plurality of first LEDs disposed on the elongated carrier, wherein the plurality of first LEDs are configured to emit first LED light, which includes (or even constitutes, i.e.,) violet-blue light having a peak wavelength λ0 in the wavelength range of 380-495 nm. The term "carrier" herein refers to an element, substrate, printed circuit board, PCB, etc., arranged to mechanically and / or electrically support the first LEDs. Thus, the plurality of first LEDs can be arranged, mounted, and / or mechanically coupled to the carrier (e.g., substrate), wherein the carrier is configured to mechanically and / or electrically support the first LEDs. The lighting device (LED filament device) also includes an elongated package that at least partially surrounds the elongated carrier and at least partially surrounds the plurality of first LEDs. The term "package" herein refers to a material, element, device, or the like configured or arranged to at least partially surround, encapsulate, and / or surround the carrier and the plurality of first LEDs. The package includes a first luminescent material comprising a first phosphor configured to at least partially convert emitted first LED light into first converted light. The first converted light includes (or even constitutes, i.e., is) green light having a green peak wavelength λ1 in the wavelength range of 505-520 nm. Therefore, the first phosphor can be described or defined as a narrowband green phosphor. "Peak wavelength" herein refers to the (primary) peak wavelength or centroid wavelength, i.e., the wavelength at which the light reaches maximum intensity. The emitted white light from the LED filament includes both green and red light, with a peak wavelength λ2 in the wavelength range of 610-680 nm (or 610-660 nm). The CCT of the emitted white light from the LED filament is in the range of 1500-2500 K. The first converted light has a spectral distribution with a full width at half maximum (FWHM) of ≤40 nm (preferably ≤35 nm, more preferably ≤30 nm, even more preferably ≤28 nm), such that at most 2% (or at most 1%, such as 0%) of the emitted white light from the LED filament is in the wavelength range below 495 nm in the visible wavelength range.

[0015] According to one embodiment of the invention, the lighting device may further include a plurality of second LEDs arranged on the carrier, wherein the plurality of second LEDs are configured to emit second LED light including red light. For example, the emitted second LED light may even constitute (i.e.) red light. It should be understood that the plurality of second LEDs constitute other LEDs besides the plurality of first LEDs. Preferably, the number of second LEDs is higher than, or even higher than, the number of first LEDs. For example, the number of second LEDs may be twice the number of first LEDs. An advantage of this embodiment is that the lighting device can be customized to achieve desired characteristics, such as including a relatively large number (or alternatively, a relatively small number) of second LEDs that sequentially emit red light.

[0016] According to one embodiment of the invention, the encapsulation may include a second light-emitting material comprising a second phosphor configured to at least partially convert at least one of emitted first LED light and first converted light into a second converted light comprising red light. For example, the second converted light may even constitute (i.e.) red light. Therefore, the second light-emitting material having the second phosphor can convert first LED light emitted from a plurality of first LEDs and / or first converted light from the encapsulation. The second phosphor may be described or defined as a narrow-band red phosphor.

[0017] According to one embodiment of the present invention, the second converted light may have a light distribution with a full width at half maximum (FWHM) of less than 30 nm.

[0018] According to one embodiment of the present invention, the second phosphor may include a narrowband phosphor, which includes a manganese-activated narrowband red fluoride phosphor with a peak emission wavelength range of 628-640 nm.

[0019] According to an embodiment of the present invention, the relationship between the phosphor concentration P1 of the first phosphor and the phosphor concentration P2 of the second phosphor satisfies Therefore, the phosphor concentration P1 of the first phosphor is at least three times the phosphor concentration P2 of the second phosphor.

[0020] According to the example, the second phosphor may include or be a manganese-activated narrow-band red phosphor.

[0021] Regarding manganese-activated narrowband red phosphors, this refers to phosphors doped with tetravalent manganese. The luminescent material of the type wherein M' comprises an alkaline earth metal cation, M comprises a basic cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, such as one or more of silicon and titanium, and wherein X comprises a monovalent anion, including at least fluorine.

[0022] The relevant basic cations (M) are sodium (Na), potassium (K), and rubidium (Rb). Alternatively, lithium and / or cesium may also be used. In a preferred example, M comprises at least potassium. In yet another example, M comprises at least rubidium. The phrase "wherein M comprises at least potassium" means, for example, in molar... Of all the M cations, some include K. ＋ Optionally, the remaining portion includes one or more other monovalent (basic) cations (see also below). In another preferred example, M includes at least potassium and rubidium. Optionally, The luminescent material has a hexagonal phase. In yet another example, The luminescent material has a cubic phase. For x=0, the composition is... .

[0023] The relevant alkaline earth cations (M') are magnesium (Mg), strontium (Sr), calcium (Ca) and barium (Ba), especially one or more of Sr and Ba.

[0024] The term "tetravalent manganese" refers to Mn 4＋ This is a well-known luminescent ion. In the formula described above, a portion of the tetravalent cation A (such as Si) is replaced by manganese. Therefore, doped with tetravalent manganese It can also be expressed as The molar percentage of manganese, i.e., the percentage of it replacing the tetravalent cation A, is typically 0.1-15%, particularly 1-12%, i.e., m is in the range of 0.001-0.15, particularly in the range of 0.01-0.12.

[0025] As stated above, X involves monovalent anions, but includes at least fluorine. Optional other monovalent anions may be selected from the group consisting of chlorine (Cl), bromine (Br), and iodine (I).

[0026] Based on one example, This includes K2SiF6 (also referred to herein as the KSiF system). As mentioned above, in another preferred example, This includes KRbSiF6 (also referred to as the K,Rb system in this paper). As mentioned above, some silicon is replaced by manganese (i.e., the molecular formula can also be described as...). or Where m is as described above, or is respectively described as KRbSiF6:Mn and K2SiF6:Mn). Since manganese substitutes for a portion of the main lattice ions and has a specific function, it is also referred to as a "dopant" or "activator". Therefore, hexafluorosilicates are made with manganese (Mn... 4＋ Doping or activation.

[0027] In a specific example, the luminescent material may include (K,Rb)₂SiF₆:Mn4＋ Alternatively or additionally, in this example, the third luminescent material may comprise K2SiF6:Mn 4＋ Alternatively or additionally, in this example, the third luminescent material may include K2TiF6:Mn 4＋ In the example, the third luminescent material may include K2(Si,Ti)F6:Mn 4＋ From the above, we can conclude that "Si, Ti" can represent one or more of Si and Ti.

[0028] According to one embodiment of the present invention, the first converted light may have a full width at half maximum (FWHM) light distribution of less than 30 nm. For example, the first phosphor may include a narrowband phosphor.

[0029] According to one embodiment of the present invention, the first phosphor may include at least one of barium magnesium aluminate (BAM), a green phosphor, and quantum dots. Therefore, the first phosphor may include BAM, a green phosphor, and / or quantum dots.

[0030] According to one embodiment of the present invention, the green peak wavelength λ1 can be in the wavelength range of 508-517 nm.

[0031] According to one embodiment of the invention, the encapsulation may include a third luminescent material comprising a third phosphor configured to at least partially convert at least one of emitted first LED light and first converted light into third converted light, wherein the third phosphor has a peak wavelength in the wavelength range of 520-590 nm. Therefore, the third luminescent material having the third phosphor can convert first LED light emitted from a plurality of first LEDs and / or first converted light from the encapsulation. Preferably, a relatively low concentration of the third phosphor relative to the first phosphor is provided so as to be on the blackbody trajectory (BBL) within a given CCT range. According to one example, the third phosphor may be a broadband (yellow) phosphor, and wherein the third converted light has a spectral distribution with a full width at half maximum (FWHM) greater than 60 nm.

[0032] According to one example of the invention, the encapsulation may include a fourth luminescent material comprising a fourth phosphor configured to at least partially convert at least one of emitted first LED light and first converted light into fourth converted light, wherein the fourth phosphor has a peak wavelength in the wavelength range of 560-610 nm. Therefore, the fourth luminescent material having the fourth phosphor can convert first LED light emitted from a plurality of first LEDs and / or first converted light from the encapsulation. The fourth phosphor may be described or defined as a narrowband fourth phosphor.

[0033] According to one embodiment of a second aspect of the invention, an LED filament device is provided, wherein an elongated carrier comprises at least partially light-transmitting material and includes a first surface and a second surface disposed opposite to the first surface, wherein a plurality of LEDs are disposed on the first surface. The first surface faces a first portion of the elongated package, and the second surface faces a second portion of the elongated package, wherein the second portion of the elongated package includes a first phosphor. The term "light-transmitting" herein means that the carrier comprises a transparent and / or translucent material, composition, and / or substance that allows light to be transmitted through the carrier. Due to the light-transmitting material of the elongated carrier, first LED light emitted from the plurality of first LEDs can be transmitted through the carrier and converted by the first phosphor disposed in the second portion of the elongated package. Another advantage of this embodiment is that the LED filament lamp can be decorative and / or aesthetically pleasing.

[0034] According to an embodiment of the present invention, an LED filament lamp is provided, comprising an LED filament assembly according to any one of the foregoing embodiments of the second aspect of the invention. The LED filament lamp includes a light-transmitting housing at least partially surrounding the at least one LED filament and a base electrically connected to the at least one LED filament, the base being used to power a plurality of LEDs of the at least one LED filament and configured to mechanically and electrically connect the lamp to a socket of a luminaire. The term "housing" herein refers to an enclosing element comprising at least partially translucent and / or transparent material, such as a cap, cover, etc. This embodiment is advantageous because the LED filament assembly according to the invention can be conveniently arranged in virtually any luminaire, lamp, or lighting device, such as tubular lighting devices, LED filament lamps, or LED filament luminaires, luminaires, lighting systems, etc. The LED filament lamp may also include a driver for powering the LEDs of the LED filament lamp.

[0035] According to one embodiment of the present invention, an LED filament lamp is provided, wherein the housing includes an amber layer. An advantage of this embodiment is that the amber layer presents an aesthetically pleasing decorative effect for the LED filament lamp. Considering the effect of the LED filament arrangement emitting white light free of violet and / or blue light, this embodiment is further advantageous because the amber layer absorbs only blue light and, due to the absence of blue light, the layer absorbs little to no light.

[0036] Other objects, features, and advantages of the invention will become apparent upon studying the following detailed disclosure, drawings, and appended claims. Those skilled in the art will recognize that different features of the invention can be combined to create embodiments different from those described below. Attached Figure Description

[0037] This and other aspects of the invention will now be described in more detail with reference to the accompanying drawings, which illustrate several embodiments of the invention.

[0038] Figure 1 An LED filament lamp according to the prior art is schematically shown.

[0039] Figure 2 The illustration schematically depicts a lighting device according to an exemplary embodiment of the first aspect of the present invention.

[0040] Figure 3 and Figure 4 An exemplary embodiment of an LED filament device according to a second aspect of the present invention is illustrated schematically.

[0041] Figure 5 A portion of an LED filament device according to an exemplary embodiment of the second aspect of the present invention is schematically shown.

[0042] Figure 6a This is an intensity graph of green light as a function of the wavelength of the first converted light, according to an exemplary embodiment of the present invention;

[0043] Figure 6b This is a graph of the intensity as a function of the wavelength of red light according to an exemplary embodiment of the present invention;

[0044] Figure 7 A portion of an LED filament device according to an embodiment of the second aspect of the invention is schematically shown in cross-section, and

[0045] Figure 8 An LED filament lamp according to an exemplary embodiment of the present invention is shown. Detailed Implementation

[0046] Figure 1 An LED filament lamp 10 according to the prior art is shown, which includes a plurality of LED filaments 20. This type of LED filament lamp 10 is very popular because it is highly decorative and offers many advantages over incandescent lamps, such as longer operating life, reduced power consumption, and increased efficiency related to the ratio between light and heat energy. This 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 filaments 20 without compromising the appearance and / or decorative aspects of the LED filaments 20 and / or the LED filament lamp 10.

[0047] Figure 2An illumination device 100 according to an exemplary embodiment of a first aspect of the present invention is schematically illustrated. The illumination device 100 is configured to emit white illumination device light 110, i.e., visible light in the wavelength range of 400-700 nm. The illumination device 100 includes a plurality of first LEDs 130 disposed on a carrier 120. The plurality of first LEDs 130 are configured to emit first LED light 140. The first LED light 140 includes / or is violet-blue light having a peak wavelength λ0 in the wavelength range of 380-495 nm. The illumination device 100 also includes an encapsulation 150 that at least partially surrounds the carrier 120 and at least partially surrounds the plurality of first LEDs 130. The encapsulation 150 includes a first luminescent material 155 comprising a first phosphor configured to at least partially convert the emitted first LED light 140 into first converted light 160. The first converted light 160 includes / or is green light having a green peak wavelength λ1 in the wavelength range of 505-520 nm. Therefore, the first phosphor can be described or defined as a narrowband green phosphor. The emitted white illumination device light 110 includes green light and red light 161, the red light 161 having a (red) peak wavelength λ2 in the wavelength range of 610-680 nm (or 610-660 nm). The emitted white illumination device light 110 has a CCT in the range of 1500-2500 K. At most 2% (or at most 1%, e.g., 0%) of the emitted white illumination device light 110 in the visible wavelength range is in the wavelength range below 495 nm. In other words, at least 98% of the white illumination device light 110 in the visible wavelength range is in the wavelength range of 500-800 nm.

[0048] Figure 3 An LED filament device 500 according to an exemplary embodiment of the second aspect of the present invention is schematically illustrated. The LED filament device 500 is configured to emit white LED filament light 505, i.e., visible light in the wavelength range of 400-700 nm. The LED filament device 500 includes at least one LED filament 510 (in... Figure 2(Seen as a single LED filament 510). Preferably, the LED filament 510 has a length L and a width W, where L > 5W. The LED filament 510 can be arranged in a straight configuration or a non-straight configuration, such as, for example, a curved configuration, a 2D / 3D helix, or a spiral. The LED filament device 500 also includes an elongated carrier 520. The elongated carrier 520 can be in the form of an element, a substrate, a printed circuit board, a PCB, etc. The elongated carrier 520 can be rigid (e.g., made of polymer, glass, quartz, metal, or sapphire) or flexible (e.g., made of polymer or metal, such as a film or foil). The LED filament device 500 includes at least one first linear array 530 of first LEDs 531 arranged on the elongated carrier 520 (in Figure 2 The LED filament assembly 500 is shown as a single first linear array 530, whereby an elongated carrier 520 is configured to mechanically and / or electrically support a plurality of first LEDs 531. The plurality of first LEDs 531 are configured to emit first LED light 540. The first LED light 540 comprises / or is violet-blue light having a peak wavelength λ0 in the wavelength range of 380-495 nm. The LED filament assembly 500 also includes an elongated package 550 that at least partially surrounds the elongated carrier 520 and at least partially surrounds the plurality of first LEDs 531. The package 550 includes a first luminescent material 555 comprising a first phosphor configured to at least partially convert the emitted first LED light 540 into first converted light 560. The first converted light 560 comprises / or is green light having a green peak wavelength λ1 in the wavelength range of 505-520 nm. Therefore, the first phosphor can be described or defined as a narrowband green phosphor. The emitted white LED filament light 505 comprises green and red light 561, the red light 561 having a (red) peak wavelength λ2 in the wavelength range of 610-680 nm (or 610-660 nm). The emitted white LED filament light 505 has a CCT in the range of 1500-2500 K. At most 2% (or at most 1%, e.g., 0%) of the emitted white LED filament light 505 in the visible wavelength range is in the wavelength range below 495 nm. In other words, at least 98% of the white LED filament light 505 in the visible wavelength range is in the wavelength range of 500-800 nm.

[0049] Figure 4 An LED filament device 500 according to an exemplary embodiment of the second aspect of the present invention is schematically shown. Figure 4 The LED filament device 500 shown corresponds to Figure 3 The LED filament device 500 is shown, and for further understanding, refer to... Figure 3 And related text. With Figure 3 compared to, Figure 4The illustrated LED filament device 500 includes a plurality of second LEDs 200 arranged on an elongated carrier 520, wherein the plurality of second LEDs 200 are configured to emit (or) light. Figure 3 The second LED light 210 of the red light 561.

[0050] Figure 5 A portion of an LED filament device 500 according to an exemplary embodiment of the second aspect of the present invention is schematically shown. It should be noted that... Figure 5 relative to Figure 3 and / or Figure 4 The LED filament device 500 shown omits many features and / or functions, and these figures are referenced to enhance understanding of the LED filament device 500. Figure 5 In this embodiment, the encapsulation 550, which at least partially surrounds the carrier 520, comprises a plurality of light-emitting materials 555, 565, 575, and 585. It should be noted that the shape and / or position of each light-emitting material 555, 565, 575, and 585 are for illustrative purposes only. Furthermore, it should be noted that the LED filament assembly 500 may include substantially any combination of the light-emitting materials 555, 565, 575, and 585. Figure 3As described in the relevant text, the LED filament device 500 includes a first luminescent material 555, which in turn includes a first (green) phosphor configured to at least partially convert emitted first LED light into first converted light, the first converted light including (or) green light having a green peak wavelength λ1 in the wavelength range of 505-520 nm. The first phosphor may include barium magnesium aluminate (BAM), a green phosphor, and / or quantum dots. The package 520 may also include a second luminescent material 565, which includes a second (red) phosphor configured to at least partially convert at least one of the emitted first LED light and the first converted light into second converted light including (or) red light. The second converted light may have a light distribution with a full width at half maximum (FWHM) of less than 30 nm. Furthermore, the second phosphor may include a narrowband phosphor, comprising a manganese-activated narrowband red fluoride phosphor with a peak emission wavelength range of 628-640 nm. It should be noted that different phosphor concentration ratios or relationships may exist between the first and second phosphors. For example, the relationship between the phosphor concentration P1 of the first phosphor and the phosphor concentration P2 of the second phosphor may satisfy P2 ≥ 3·P1, that is, the concentration of the second phosphor is at least three times higher than the concentration of the first phosphor. The encapsulation 520 of the LED filament device 500 may also include a third luminescent material 575 comprising a third (yellow) phosphor configured to at least partially convert the emitted first LED light and / or first converted light into third converted light. The third phosphor may be a broadband phosphor. The third converted light may have a spectral distribution with a full width at half maximum (FWHM) greater than 60 nm. Therefore, the LED filament device 500 may have a configuration of a (narrow-band) first (green) phosphor, a second (red) phosphor (which is preferably also narrow-band), and a third (yellow) phosphor (e.g., YAG). The package 520 of the LED filament device 500 may also include a fourth luminescent material 585, which includes a fourth phosphor configured to at least partially convert the emitted first LED light and / or first converted light into fourth converted light, wherein the fourth phosphor has a peak wavelength in the wavelength range of 560-610 nm.

[0051] Figure 6a and Figure 6b The intensity distribution (arbitrary units on the y-axis) is schematically disclosed as a function of wavelength (on the x-axis, nm). Figure 6a The leftmost distribution (curve) shows the excitation of the first phosphor included in the first luminescent material of the encapsulation (i.e., the first phosphor can be excited at this wavelength). The first phosphor can be excited to approximately 460 nm. It should be noted that... Figure 6aThe first phosphor excitation curve shown is an example, and other phosphor excitation distributions or curves are also possible. Figure 6a The rightmost distribution (curve) shows that the emitted first LED light is converted into first converted light via an encapsulation comprising a first luminescent material, which in turn comprises a first phosphor. This (green) emission spectrum has a green (dominant) peak wavelength λ1 in the wavelength range of 505-520 nm. Figure 6a In the middle, the green (main) peak wavelength λ1 is approximately 515 nm. Figure 6b The leftmost distribution (curve) shows the excitation of the second phosphor included in the second luminescent material of the encapsulation (i.e., the second phosphor can be excited at this wavelength). It should be noted that... Figure 6b The second phosphor excitation curve shown is an example, and other phosphor excitation distributions or curves are also possible. Figure 6b The rightmost distribution (curve) shows the emitted white LED filament light, which includes red light with a red (dominant) peak wavelength λ2 in the wavelength range of 610-680 nm (or 610-660 nm). A second phosphor, which may include KSiF, can emit red light with a narrow band around approximately 630 nm. This narrow band of the second phosphor is advantageous compared to other phosphors with a "long tail" in the far-red region, as light with a "long tail" in the far-red region is further away from the eye's sensitivity peak and therefore has lower luminous efficiency.

[0052] Figure 7 A portion of an LED filament assembly 500 according to an embodiment of a second aspect of the invention is schematically shown in cross-section. The elongated carrier 520 of the LED filament 510 comprises a material that is at least partially transparent. The elongated carrier 520 includes a first surface 580 and a second surface 585 disposed opposite to the first surface 580. A plurality of LEDs 531 are disposed on the first surface 580. The first surface 580 faces a first portion 590 of an elongated package 550, and the second surface 585 faces a second portion 595 of the elongated package 550. The second portion 595 of the elongated package 550 includes a first phosphor.

[0053] Figure 8An LED filament lamp 600 according to an embodiment of the present invention is schematically shown. The LED filament lamp 600, which can constitute substantially any kind of lamp or luminaire, includes an LED filament assembly 500 of any of the foregoing embodiments according to the second aspect of the present invention. The LED filament lamp 600 also includes a light-transmitting enclosure 610, exemplified by a bulb shape. The enclosure 610 at least partially surrounds the LED filament(s) of ...

[0054] Those skilled in the art will recognize that the present invention is by no means limited to the preferred embodiments described above. Rather, many modifications and variations are possible within the scope of the appended claims. For example, one or more of the LED filaments 510, the elongated carrier 520, etc., may have different shapes, sizes, and / or dimensions than those depicted / described.

Claims

1. A lighting device (100) configured to emit white lighting light (110), the lighting device comprising: Carrier (120) A plurality of first light-emitting diodes (LEDs) (130) are arranged on the carrier, wherein the plurality of first LEDs are configured to emit first LED light (140), the first LED light comprising violet-blue light having a peak wavelength λ0 in the wavelength range of 380 nm to 495 nm. An encapsulation (150) at least partially surrounds the carrier and at least partially surrounds the plurality of first LEDs, wherein the encapsulation includes a first light-emitting material (155), the first light-emitting material (155) including a first phosphor, the first phosphor being configured to at least partially convert the emitted light from the first LEDs into first converted light (160), the first converted light (160) comprising green light having a peak wavelength λ1 in the wavelength range of 505 nm to 520 nm. The emitted white light from the illumination device includes: The green light, and Red light with a peak wavelength λ2 in the wavelength range of 610 nm to 680 nm. The emitted white illumination device light has a correlated color temperature (CCT) in the range of 1500K to 2500K, and The first converted light has a spectral distribution with a full width at half maximum (FWHM) of less than or equal to 40 nm, such that at most 2% of the emitted white illumination device light is in the wavelength range below 495 nm within the visible wavelength range.

2. The lighting device according to claim 1, further comprising: A plurality of second LEDs (200a-d) are arranged on the carrier, wherein the plurality of second LEDs are configured to emit second LED light (210) including the red light.

3. The lighting device according to claim 1 or 2, wherein the encapsulation comprises a second light-emitting material (565), the second light-emitting material (565) comprising a second phosphor, the second phosphor being configured to at least partially convert at least one of the emitted first LED light and the first converted light into a second converted light (240) including the red light.

4. The lighting device according to claim 3, wherein the spectral distribution of the second converted light has a full width at half maximum (FWHM) of less than 30 nm.

5. The lighting device according to claim 4, wherein the second phosphor comprises a narrow-band phosphor, the narrow-band phosphor comprising a manganese-activated narrow-band red fluoride phosphor with a peak emission wavelength range of 628 nm to 640 nm.

6. The lighting device according to claim 5, wherein the relationship between the phosphor concentration P1 of the first phosphor and the phosphor concentration P2 of the second phosphor satisfies P2≥3·P1.

7. The lighting device according to any one of the preceding claims, wherein the first phosphor comprises at least one of the following: barium magnesium aluminate (BAM), green phosphor, and quantum dots.

8. The lighting device according to any one of the preceding claims, wherein the peak wavelength λ1 is in the wavelength range of 508 nm to 517 nm.

9. The lighting device according to any one of the preceding claims, wherein the encapsulation comprises a third light-emitting material (575), the third light-emitting material (575) comprising a third phosphor, the third phosphor being configured to at least partially convert at least one of the emitted first LED light and the first converted light into a third converted light (340), wherein the third phosphor has a peak wavelength in the wavelength range of 520 nm to 590 nm.

10. The lighting device according to claim 9, wherein the third phosphor is a broadband phosphor, and wherein the spectral distribution of the third converted light has a full width at half maximum (FWHM) greater than 60 nm.

11. The lighting device according to claim 1, wherein the lighting device is an LED filament device comprising at least one LED filament (510), wherein the carrier is an elongated carrier, and the plurality of first LEDs (531) are arranged in at least one first linear array (530) on the elongated carrier (520).

12. The LED filament device of claim 11, wherein the elongated carrier comprises at least partially light-transmitting material and includes a first surface (580) and a second surface (587) disposed opposite to the first surface, wherein the plurality of LEDs are disposed on the first surface. The first surface faces the first portion (590) of the elongated package, and the second surface faces the second portion (595) of the elongated package. The second portion of the elongated package includes the first phosphor.

13. An LED filament lamp (600), comprising: The LED filament device according to claim 11 or 12, A light-transmitting housing (610) at least partially surrounds the at least one LED filament, and The base (620) is electrically connected to the at least one LED filament for supplying power to the plurality of LEDs of the at least one LED filament and is configured to mechanically and electrically connect the lamp to a socket of the luminaire.

14. The LED filament lamp (600) according to claim 13, wherein the housing includes an amber layer.

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