Light device

Abstract

A lighting device comprises a LED light source providing LED light. A luminescent converter enclosing the LED light source comprises a first luminescent material converting the LED light into first converted light at 627-635 nm, and a second luminescent material converting the LED light into second converted light at 600-622 nm. The first luminescent material is of the type M'xM2-2xAX6 doped with tetravalent manganese. M' comprises an alkaline earth cation. M comprises an alkaline cation, x is in the range of 0-1. A comprises a tetravalent cation. X comprises a monovalent anion at least comprising fluorine. The second luminescent material is of a quantum dot type. The first and second converted light have a respective first full width half maximum ≤30 nm and ≤45 nm respectively. The device light is white light having a correlated color temperature range 1700-6500K and a color rendering index of at least 80.

Description

[0001] Light device

[0002] FIELD OF THE INVENTION

[0003] The present invention generally relates to light devices configured to provide device light. More specifically, the present invention is related to a light device comprising a light emitting diode (LED) covered by an encapsulant comprising a luminescent material.

[0004] BACKGROUND OF THE INVENTION

[0005] A trend in the development of LED lighting is the development of lighting arrangements capable of providing white light having any desired color temperature. For this purpose, the lighting arrangements are configured with LED’s covered by encapsulants comprising various luminescent materials.

[0006] However, a remaining issue is a desire to improve the quality of white light and / or efficiency of such LED light sources.

[0007] SUMMARY OF THE INVENTION

[0008] It is of interest to provide a lighting device that overcomes drawbacks of the prior art as discussed above.

[0009] This and other objects are achieved in a first aspect by providing a lighting device having the features of the appended independent claim. Preferred embodiments are defined in the appended dependent claims.

[0010] Hence, according to the present invention, there is provided a lighting device configured to provide light device light, preferably light in the blue wavelength range. The lighting device comprises a LED light source configured to provide LED light. The lighting device may in various embodiments be in the form of a LED package.

[0011] A luminescent converter is configured in a light receiving relationship with said LED light source, i.e. the LED light source is at least partly enclosed by the luminescent converter. The luminescent converter comprises a first luminescent material configured to partially convert the LED light into first converted light having a first peak emission wavelength ( I ) and a second luminescent material configured to partially convert the LED light into second converted light having a second peak emission wavelength (X2). The first peak emission wavelength I is in a wavelength range from 627 nm to 635 nm and the second peak emission wavelength X2 is in a wavelength range from 600 nm to 622 nm. In an embodiment, the absolute difference between the first peak emission wavelength XI and the second peak emission wavelength X2, | I - X2|, is in a range of at least 10 nm, such as at least 12 nm.

[0012] The first converted light has a first full width half maximum (FWHM1) equal to or less than 30 nm and the second converted light has a second full width half maximum (FWHM2) equal to or less than 45 nm.

[0013] The first luminescent material is 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 in the range of 0-1. A comprises a tetraval ent cation, for instance comprising one or more of silicon and titanium. X comprises a monovalent anion at least comprising fluorine. Relevant alkaline cations (M) are sodium (Na), potassium (K) and rubidium (Rb). Optionally, also lithium and / or cesium may be applied. In a preferred embodiment, M comprises at least potassium. In yet another embodiment, M comprises at least rubidium. The phrase “wherein M comprises at least potassium” indicates for instance that of all M cations in a mole M’xM2-2xAX6 , a fraction comprises K+and an optionally remaining fraction comprises one or more other monovalent (alkaline) cations (see also below). In another preferred embodiment, M comprises at least potassium and rubidium. Optionally, the M’xM2-2xAX6 luminescent material has the hexagonal phase. In yet another embodiment, the M’xM2-2xAX6 luminescent material has the cubic phase. For x=0, the composition is M2AX6. Relevant alkaline earth cations (M’) are magnesium (Mg), strontium (Sr), calcium (Ca) and barium (Ba), especially one or more of Sr and Ba. The term “tetraval ent manganese” refers to Mn4+. This is a well-known luminescent ion. In the formula as indicated above, part of the tetravalent cation A (such as Si) is being replaced by manganese. Hence, M’xM2-2xAX6 doped with tetravalent manganese may also be indicated as M’xM2-2xAi-mMnmX6. The mole percentage of manganese, i.e. the percentage it replaces the tetravalent cation A will in general be in the range of 0.1-15 %, especially 1-12 %, i.e. m is in the range of 0.001-0.15, especially in the range of 0.01-0.12. As indicated above, X relates to a monovalent anion, but at least comprises fluorine. Other monovalent anions that may optionally be present may be selected from the group consisting of chlorine (Cl), bromine (Br), and iodine (I). In an embodiment, M’xM2-2xAX6 comprises K2SiFe (indicated herein also as KSiF system, or KSiF phosphor or KSiF luminescent material). As indicated above, in another preferred embodiment, M’xM2-2xAX6 comprises KRbSiFe (herein also indicated as K,Rb system). As indicated above, part of silicon is replaced by manganese (i.e. the formula may also be described as K2Sii-mMnmF6 or KRbSii-mMnmFe, with m as indicated above, or as KRbSiFe:Mn and K2SiFe:Mn, respectively). As manganese replaces part of a host lattice ion and has a specific function, it is also indicated as “dopant” or “activator”. Hence, the hexafluorosilicate is doped or activated with manganese (Mn4+). In specific embodiments, the luminescent material may comprise (K,Rb)2SiF6:Mn4+. Alternatively or additionally, in embodiments the third luminescent material may comprise K2SiFe:Mn4+. Alternatively or additionally, in embodiments the third luminescent material may comprise K2TiFe:Mn4+. In embodiments, the third luminescent material may comprise K2(Si,Ti)Fe:Mn4+. As can be derived from the above, “Si,Ti” may indicate one or more of Si and Ti.

[0014] The second luminescent material is of a quantum dot (QD) type. Most known quantum dots with emission in the visible range are based on cadmium selenide (CdSe) with a shell such as cadmium sulfide (CdS) and (or) zinc sulfide (ZnS) shell. Cadmium free quantum dots, such as indium phosphode (InP), and / or copper indium sulfide (CuInS2) and / or silver indium sulfide (AgInS2) can also be used.

[0015] In embodiments, he first peak emission wavelength XI is in a wavelength range from 630 nm to 635 nm. In embodiments, the second peak emission wavelength X2 is in a wavelength range from 605 nm to 620 nm, such as in the range from 610 - 620 nm.

[0016] The device light is white light having a correlated color temperature (CCT) in a range from 1700 K to 6500 K and a color rendering index of at least 80. For example, in embodiments, the device light may comprise the first luminescent light, the second luminescent light and optionally part of the LED light. In embodiments, the device light CCT may be in a range from 1700 K to 3500 K, or in the range of 1700 K to 2500 K, and a CRI of at least 80, or at least 88, or at least 90.

[0017] In other words, such a lighting device comprises a wavelength converter comprising KSiF phosphor and ultra-narrow bandwidth red QDs, for example dispersed in a polymer or inorganic matrix. KSiF phosphor has the advantage of showing no self-absorption and red QDs have the advantage that the emission can be tuned by changing the size of the quantum dot during its synthesis. The combination of KSiF phosphor and QDs thus provides red enriched device light with contributions of both the KSiF phosphor and red QDs. Furthermore, such lighting device has the advantage that the quantum dots may be tuned with respect to the KSiF phosphor such that the quantum dots do not absorb any KSiF light while enhancing the red component in the device light. The matrix material may be selected from the group consisting of PE (polyethylene), PP (polypropylene), PEN (polyethylene napthalate), PC (polycarbonate), polymethylacrylate (PMA), polymethylmethacrylate (PMMA) (Plexiglas or Perspex), cellulose acetate butyrate (CAB), silicone, polyvinylchloride (PVC), polyethyleneterephthalate (PET), (PETG) (glycol modified polyethyleneterephthalate), PDMS (poly dimethylsiloxane), and COC (cyclo olefin copolymer). However, in another embodiment the support may comprise an inorganic material. Preferred inorganic materials are selected from the group consisting of glasses, (fused) quartz, transmissive ceramic materials, and silicones. Especially preferred are PMMA, transparent PVC, or glass as material for the support.

[0018] In various embodiments, A may comprise one or more of silicon and titanium, and / or wherein FWHM2 < 30 nm. The obtained effect is further improved efficiency.

[0019] In various embodiments, 2 is in a wavelength range from 608 nm to 618 nm. This provides a more optimized red light rendition and CRI.

[0020] In various embodiments, the contribution of the first converted light to the spectral power distribution of the device light is in a range from 7.5 % to 30 %, preferably 7.5% to 15%. This provides a more optimized improved efficiency.

[0021] In embodiments, the first full width half maximum (FWHM1) may be equal to or less than 25 nm, preferably equal to or less than 20 nm, more preferably equal to or less than 18 nm, most preferably equal to or less than 15 nm.

[0022] The luminescent converter may comprise a third luminescent material configured to partly convert the LED light into third converted light having a third peak emission wavelength ( 3) wherein 3 is in a wavelength range from 510 nm to 580 nm and the third converted light having a third full width half maximum (FWHM3) equal to or greater than 60 nm. Preferably, FWHM3 is at least 70 nm, more preferably at least 80 nm, most preferably at least 90 nm. For example, the third luminescent material may be of the type A3BsOi2:Ce, wherein A may comprise one or more of Y, La, Gd, Tb and Lu, preferably at least one or more of Y, Gd, Tb and Lu, more preferably one or more of Y, Gd and Lu, more preferably one or more of Y and Lu, and B may comprise one or more of Al, Ga, In and Sc, preferably one or more of Al and Ga, more preferably at least Al, more preferably essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B may comprise aluminum (Al); however, in addition to aluminum, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), especially up to about 20% of B, more especially up to about 10 % of B (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and / or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Y i-xLux)3BsOi2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1. The term “:Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. For instance, in the case of (Y i- xLux)3AlsOi2:Ce, part of Y and / or Lu is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.89Ceo.oi)3AlsOi2. Ce in garnets is substantially or only in the trivalent state.

[0023] Such a configuration with a third luminescent material provides white light with an improved quality especially with respect to the CRI of the device light.

[0024] The device light may comprise the first luminescent light, the second luminescent light and the LED light, wherein the LED light has a fourth peak wavelength ( 4) in a wavelength range from 430 nm to 480 nm, preferably in a wavelength range 440 nm to 470 nm.

[0025] Such a configuration with blue LED light provides full spectrum white light with an improved quality especially with respect to the CRI of the device light.

[0026] The contribution of the second converted light to spectral power distribution of the device light may be greater than the contribution of the first converted light to spectral power distribution of the device light. In other words, the contribution of the quantum dots to the spectral power distribution of the device light is larger than that of the KSiF type of light resulting in improved efficiency.

[0027] In various embodiments, the first luminescent material may have a first percentage by volume (VI) in the luminescent converter, the second luminescent material may have a second percentage by weight (V2) in the luminescent converter and a ratio between VI and V2 may be such that VI IN 2 > 1, preferably V1 / V2 > 1.5, more preferably V1 / V2 > 2, such as V1 / V2 > 3. This means that the volume fraction of KSiF is higher than the volume percentage of the quantum dots. The obtained effect is improved absorption of the LED light.

[0028] In some embodiments, the luminescent converter may comprise a polymer matrix and the percentage of luminescent material in the luminescent converter may be in a range from 3 % by volume to 30 % by volume, preferably 4 % by volume to 12 % by volume.

[0029] Such a configuration, provides optimal conversion because on the one hand the concentration is sufficiently high such that substantial amount of LED light can be converted, but on the other hand the concentration is not too high such that trapping of converted light in the converter is limited.

[0030] In a further aspect there is provided a LED filament comprising a lighting device as summarized above. Especially a LED filament configuration i.e. the LED light source comprises a plurality of (blue) LEDs arranged on an elongated carrier and the luminescent converter is an elongated encapsulant covering the elongated carrier (e.g. from both sides) and the plurality of LEDs, benefits for the invention. The reason is that LED filaments typically provide white light having a very low CCT e.g. in a range from 1700 K to 2800 K which implies a lot of and high quality red light is needed.

[0031] In yet further aspects there is provided a lamp or a luminaire comprising at least one lighting device or a or LED filament as summarized above. Embodiments of such a lamp or luminaire may comprise a controller and at least two different lighting devices as summarized above, each lighting device having a CCT that is different from a CCT of any other lighting device, e.g. a difference of at least 500 K, or at least 700 K, or at least 1000 K. For example, the LED filaments may be used e.g. one according to the invention and another LED filament e.g. having a higher CCT, such as for example 4000 K or 4500 K.

[0032] Such a lamp or luminaire provides white light with a tunable CCT and having relatively high CRI and / or red rendition.

[0033] The terms “violet light” or “violet emission” especially relates to light having a wavelength in the range of about 380-440 nm. The terms “blue light” or “blue emission” especially relates to light having a wavelength in the range of about 440-490 nm (including some violet and cyan hues), more specifically 440-480 nm, even more specifically 440-460 nm. The terms “green light” or “green emission” especially relate to light having a wavelength in the range of about 490-560 nm. The terms “yellow light” or “yellow emission” especially relate to light having a wavelength in the range of about 560-590 nm. The terms “orange light” or “orange emission” especially relate to light having a wavelength in the range of about 590-620. The terms “red light” or “red emission” especially relate to light having a wavelength in the range of about 620-750 nm. The terms “visible”, “visible light” or “visible emission” refer to light having a wavelength in the range of about 380-750 nm.

[0034] The term “white light” herein, is known to the person skilled in the art. It especially relates to light having a correlated color temperature (CCT) between about 1800 K and 20000 K, such as between 2000 and 20000 K, especially 2700-20000 K, for general lighting especially in the range of about 2700 K and 6500 K. In embodiments, for backlighting purposes the correlated color temperature (CCT) may especially be in the range of about 7000 K and 20000 K. Yet further, in embodiments the correlated color temperature (CCT) is especially within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), especially within about 10 SDCM from the BBL, even more especially within about 5 SDCM from the BBL.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] 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.

[0037] Fig. 1 schematically illustrates a cross-sectional view of a lighting device, Figs. 2a and 2b schematically illustrate graphs of emission and absorption spectra,

[0038] Figs. 3a-f schematically illustrate a respective spectrum of device light, Fig. 4 schematically illustrates a lamp, and Fig. 5 schematically illustrate a luminaire.

[0039] DETAILED DESCRIPTION

[0040] As illustrated in figure 1, a lighting device 100 configured to provide device light comprises a LED light source 101 configured to provide LED light. The lighting device 100 may in various embodiments be in the form of a LED package.

[0041] A luminescent converter 160 is configured in a light receiving relationship with the LED light source 101, which means that the LED light source 101 is at least partly enclosed by the luminescent converter 160. The luminescent converter 160 comprises a first luminescent material 162 configured to partially convert the LED light into first converted light having a first peak emission wavelength ( I ) and a second luminescent material 163 configured to partially convert the LED light into second converted light having a second peak emission wavelength (X2). The first luminescent material 162 is of the type M’xM2-2xAX6 doped with tetravalent manganese. M’ comprises an alkaline earth cation, M comprises an alkaline cation, and x is in the range of 0-1. A comprises a tetraval ent cation, X comprises a monovalent anion at least comprising fluorine.

[0042] The second luminescent material 163 is of a quantum dot (QD) type.

[0043] XI is in a wavelength range from 627 nm to 635 nm and X2 is in a wavelength range from 600 nm to 622 nm. The first converted light has a first full width half maximum (FWHM), equal to or less than 30 nm and wherein the second converted light has a second full width half maximum (FWHM2) equal to or less than 45 nm. The device light is white light having a correlated color temperature (CCT) in a range from 1700 K to 6500 K and a color rendering index of at least 80. For example, in embodiments, the device light may comprise the first luminescent light, the second luminescent light and optionally part of the LED light. In embodiments, the device light CCT may be in a range from 2000 K to 3500K and a CRI of at least 88.

[0044] The lighting device 100 may be configured such that A comprises one or more of silicon and titanium and / or wherein FWHM2 < 30 nm.

[0045] The lighting device 100 may be configured such that X2 is in a wavelength range from 608 nm to 618 nm.

[0046] The lighting device 100 may be configured such that the contribution of the first converted light to the spectral power distribution of the device light is in a range from 7.5% to 30%, preferably 7.5% to 15%.

[0047] The lighting device 100 may be configured such that the luminescent converter 160 comprises a third luminescent material 164 configured to partly convert the LED light into third converted light having a third peak emission wavelength (X3) wherein X3 is in a wavelength range from 510 nm to 580 nm and the third converted light has a third full width half maximum (FWHM3) equal to or greater than 60 nm, preferably at least 70 nm, more preferably at least 80 nm, most preferably at least 90 nm.

[0048] The lighting device 100 may be configured such that the third luminescent material 164 is of the type AsELOnT'e. In such configurations, A comprises one or more of Y, La, Gd, Tb and Lu, preferably at least one or more of Y, Gd, Tb and Lu, more preferably one or more of Y, Gd and Lu, more preferably one or more of Y and Lu. In such configurations, B comprises one or more of Al, Ga, In and Sc, preferably one or more of Al and Ga, more preferably at least Al, more preferably essentially entirely Al. The lighting device 100 may be configured such that the device light comprises the first luminescent light, the second luminescent light and the LED light, wherein the LED light has a fourth peak wavelength ( 4) in a wavelength range from 430 nm to 480 nm.

[0049] The lighting device 100 may be configured such that the contribution of the second converted light to spectral power distribution of the device light is greater than the contribution of the first converted light to spectral power distribution of the device light.

[0050] The lighting device 100 may be configured such that the first luminescent material 162 has a first percentage by volume (VI) in the luminescent converter 160, the second luminescent material 163 has a second percentage by weight (V2) in the luminescent converter (160). In such configurations, the ratio V1 / V2 > 1.

[0051] The lighting device 100 may be configured such that the luminescent converter 160 comprises a polymer matrix and the percentage of luminescent material in the luminescent converter 160 is in a range from 3 % by volume to 30 % by volume, preferably 4 % by volume to 12 % by volume.

[0052] The lighting device 100 thus comprises a wavelength converter 160 comprising KSiF phosphor and ultra-narrow bandwidth, i.e. <30nm, red QDs having a dominant peak wavelength in a range from 600 to 622nm, for example dispersed in a polymer matrix.

[0053] Figure 2a illustrates a KSiF emission spectrum 201 and a KSiF absorption spectrum 202 and, as figure 2a illustrates, KSiF phosphor has the advantage of showing no self-absorption, however, its emission is sticked to and centered around 631 nm in a wavelength interval from 607-649 nm.

[0054] Figure 2b illustrates a red QD emission spectrum 211 and a red QD absorption spectrum 212 and, as figure 2b illustrates, red QDs have an overlap between its emission spectrum 211 and absorption spectrum 212. The red QDs have the advantage that the emission can be tuned in wavelength by changing the size of the quantum dot during its synthesis.

[0055] Because the main emission part of the KSiF peak in its emission spectrum 201 starts at 607nm as illustrated in figure 2a and, as illustrated in figure 2b, red quantum dots have an overlap in the absorption spectrum 212 and emission spectrum 211, the red light emission at the short-wavelength-red side of the KSiF peak is increased. In order to avoid absorption of KSiF light by the red QDs the QDs are configured such that the peak wavelength of the QDs is tuned (during manufacturing of the QDs) to a range from 595 to 610nm and the FWHM is ultra-narrow i.e. < 27nm. An arrow 213 in figure 2b illustrates this tuning to the wavelength range 595 nm to 610 nm.

[0056] The outcome of such a configuration is, as discussed above, device light in the form of red enriched light with contributions of both the KSiF phosphor and red QDs. Figures 3a-e together with the table below illustrate a respective spectrum of device light produced by a lighting device 100 having a luminescent converter of different configurations in terms of percentage of contribution to the total spectral power distribution of the device light.

[0057] As indicated in the table above, configurations with no KSiF self-absorption and high efficiency that produces red enriched device light are those where 2 is 600 nm and 610 nm. Device light spectra for these two configurations are illustrated in figures 3c and 3d, respectively.

[0058] Figure 3f illustrates a device light spectrum for a configuration with an LED emitting blue light at 450 nm and where the QD peak X2 is at 610 nm with an FWHM of 25 nm and a CTT at 2700K. As seen in figure 3f, such a configuration provides an even more pronounced red enriched device light than the configurations producing the device light illustrated in the spectra of Figures 3c and 3d.

[0059] A lamp 400 or a luminaire 500 may comprise at least one lighting device 100 as described above. This is illustrated in figures 4 and 5. Figure 4 illustrates a lamp 400 comprising a lighting device 100 and a base 402 for electrically and mechanically connecting the lamp 400 to, e.g., a socket 501 of a luminaire 500 (as illustrated in figure 5) and an envelope 403 at least partly enclosing one or more lighting devices, for example in the form of one or more 100 LED filaments 40 that comprises a lighting device 100 as described above.

[0060] As exemplified in figure 5, the lamp 400 or luminaire 500 may comprise a controller 502 and at least two different lighting devices 100 as described above, each lighting device 100 having a CCT that is different from a CCT of any other lighting device 100.

[0061] The term “plurality” refers to two or more.

[0062] The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.

[0063] The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’.

[0064] The term “and / or” especially relates to one or more of the items mentioned before and after “and / or”. For instance, a phrase “item 1 and / or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of' but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species".

[0065] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0066] The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

[0067] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0068] Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

[0069] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0070] The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments ol) the method as described herein.

[0071] The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

[0072] The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and / or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and / or shown in the attached drawings.

[0073] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

CLAIMS:

1. A lighting device (100) configured to provide device light, comprising: a light emitting diode, LED, light source (101) configured to provide LED light; a luminescent converter (160) configured in a light receiving relationship with said LED light source (101), the luminescent converter (160) comprising a first luminescent material (162) configured to partially convert the LED light into first converted light having a first peak emission wavelength, I, and a second luminescent material (163) configured to partially convert the LED light into second converted light having a second peak emission wavelength, X2; and wherein the first luminescent material (162) is 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 in the range of 0-1, wherein A comprises a tetraval ent cation , wherein X comprises a monovalent anion at least comprising fluorine; wherein the second luminescent material (163) is of a quantum dot, QD, type; wherein XI is in a wavelength range from 627 nm to 635 nm and X2 is in a wavelength range from 600 nm to 622 nm; wherein the first converted light has a first full width half maximum, FWHM1, equal to or less than 30 nm and wherein the second converted light has a second full width half maximum, FWHM2, equal to or less than 45 nm; and wherein the device light is white light having a correlated color temperature, CCT, in a range from 1700 K to 6500 K and a color rendering index of at least 80.

2. The lighting device (100) according to claim 1, wherein A comprises one or more of silicon and titanium, and wherein FWHM2 < 30 nm.

3. The lighting device (100) according to claim 1 or claim 2, wherein X2 is in a wavelength range from 608 nm to 618 nm.

4. The lighting device (100) according to any one of claims 1 to 3, wherein the contribution of the first converted light to the spectral power distribution of the device light is in a range from 7.5 % to 30 %, preferably 7.5 % to 15 %.

5. The lighting device (100) according to any one of claims 1 to 4, wherein the luminescent converter (160) comprises a third luminescent material (164) configured to partly convert the LED light into third converted light having a third peak emission wavelength, A3, wherein A3 is in a wavelength range from 510 nm to 580 nm and the third converted light has a third full width half maximum, FWHM3, equal to or greater than 60 nm.

6. The lighting device (100) according to claim 5, wherein the third luminescent material (164) is of the type AsBsOnT'e. wherein:A comprises one or more of Y, La, Gd, Tb and Lu, preferably at least one or more of Y, Gd, Tb and Lu, more preferably one or more of Y, Gd and Lu, more preferably one or more of Y and Lu, andB comprises one or more of Al, Ga, In and Sc, preferably one or more of Al and Ga, more preferably at least Al, more preferably essentially entirely Al.

7. The lighting device (100) according to any one of claims 1 to 6, wherein the device light CCT is in a range from 2000 K to 3500 K and a CRI of at least 88.

8. The lighting device (100) according to any one of claims 1 to 7, wherein the device light comprises the first luminescent light, the second luminescent light and the LED light, wherein the LED light has a fourth peak wavelength, A4, in a wavelength range from 430 nm to 480 nm.

9. The lighting device (100) according to any one of claims 1 to 8, wherein the contribution of the second converted light to spectral power distribution of the device light is greater than the contribution of the first converted light to spectral power distribution of the device light.

10. The lighting device (100) according to any one of claims 1 to 9, wherein: the first luminescent material (162) has a first percentage by volume, VI, inthe luminescent converter (160), the second luminescent material (163) has a second percentage by weight, V2, in the luminescent converter (160), and wherein: the ratio V1 / V2 > 1.

11. The lighting device (100) according to any one of claims 1 to 10, wherein the luminescent converter (160) comprises a polymer matrix and wherein the percentage of the combined first and the second luminescent material in the luminescent converter (160) is in a range from 3 % by volume to 30 % by volume, preferably 4 % by volume to 12 % by volume.

12. The lighting device (100) according to any one of claims 1 to 11, wherein the lighting device (100) is a LED package.

13. A LED filament (40) comprising a lighting device (100) according to any one of claims 1 to 11.

14. A lamp (400) or a luminaire (500) comprising at least one lighting device (100) according to any one of claims 1 to 12 or a or LED filament (40) according to claim 13.

15. The lamp (400) or luminaire (500) according to claim 14, comprising a controller (502) and at least two different lighting devices (100) according to any one of claims 1 to 12, each lighting device (100) having a CCT that is different from a CCT of any other lighting device (100).

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