Light source with disinfection function

Abstract

The invention provides a light generating system (1000) configured to generate system light (1001), wherein the light generating system (1000) comprises a first light generating device (110), wherein: (A) the first light generating device (110) comprises a first light source (10) and a first luminescent converter (210); (B) the first light source (10) comprises a solid state light source, wherein the first light source (10) is configured to generate first light source light (11) having a first light source centroid wavelength (λ s,1 ) selected from the range of 380 nm - 420 nm; (C) the first luminescent converter (210) is configured to convert at least part of the first light source light (11) into first converter light (211) having a first converter centroid wavelength (λ c,1 ) selected from the green-yellow wavelength range; (D) the first light generating device (110) is configured to generate first device light (111) having a spectral power distribution in the wavelength range of 380 nm - 780 nm of which at least 60% of the spectral power is provided by the first light source light (11) and at most 40% of the spectral power is provided by the first converter light (211).

Description

TECHNICAL FIELD

[0001] The present invention relates to a light generating system and to a lighting device comprising such a light generating system. Furthermore, the present invention also relates to a method for processing at least part of a space or an object. BACKGROUND

[0002] Light sources for emitting light having a spectral power distribution in the range of 390-420 nm are known in the art. For example, US2020 / 0390915 describes a light source for emitting an emitted light having a spectral power distribution (SPD), the light source comprising a plurality of light emitters, the plurality of light emitters comprising at least two violet solid state emitters having different peak wavelengths; wherein the emitted light has a chromaticity within a Duv distance of less than 5E-3 from the Planckian locus, wherein the chromaticity is calculated using the CIE 1964 10°C MF; and wherein at least 25% of the power within the SPD is in the range of 380-430 nm.

[0003] US2020 / 390915A1 discloses a light source for emitting an emitted light having an SPD, the light source comprising: (a) a plurality of light emitters, comprising at least one violet solid state emitter; (b) at least one phosphor; wherein the light emitters and the at least one phosphor are configured such that: at least 25% of the power within the SPD is in the range of 390-420 nm, and the emitted light has a chromaticity within a Duv distance of less than 5 points from the Planckian locus.

[0004] US2016030610A1 discloses a luminaire. The luminaire includes at least one first light source emitting at a peak wavelength in a range of about 380 nm to about 420 nm, and at least one second light source emitting at a different peak wavelength, wherein the combined light output of the at least one first light source and the at least one second light source emits a colored light perceived as white light. The definition of white light is having a color rendering index (CRI) value greater than about 50. The at least one second light source emitting at a different peak wavelength consists of an xy coordinate on the CIE 1931 xy color space diagram that is above the black body curve, within a boundary region defined by a first line of approximately y = 2.23989x - 0.382773 and a second line of approximately y = 1.1551x - 0.195082. The combined light output has a spectral energy proportion measured in the range of about 380 nm to about 420 nm greater than about 20%.

[0005] US 2017 / 030555 Al discloses an apparatus for inactivating microorganisms. The apparatus includes a light emitter and at least one light conversion material arranged to convert at least a portion of light from the light emitter. Any light emitted from the light emitter and converted light emitted from the at least one light conversion material mix to form a combined light having a spectral energy proportion measured in the range of about 380 nm to about 420 nm of greater than about 20%. In another embodiment, the apparatus includes a light emitter configured to emit light having a wavelength in the range of 380 nm to 420 nm, and includes at least one light conversion material comprising at least one optical brightener and configured to emit second light. The first light exiting the apparatus and the second light exiting the apparatus mix to form a combined light that is white. SUMMARY

[0006] UV light has been used for disinfection for more than 100 years. Wavelengths between about 190 nm and 300 nm can be strongly absorbed by nucleic acids, which can lead to defects in the genome of living organisms. This is desirable for inactivating (killing) bacteria and viruses, but can also have undesired side effects on humans. Therefore, the choice of radiation wavelength, radiation intensity, and irradiation duration can be limited in environments where people can reside, such as offices, public transportation, cinemas, restaurants, shops, etc., thus limiting the disinfection capabilities. Especially in such environments, additional disinfection measures can be beneficial to prevent the spread of bacteria and viruses, such as influenza or novel (coronavirus) viruses, like COVID-19, SARS, and MERS.

[0007] It appears that there is a need for systems that can provide alternative ways of air treatment, such as disinfection. Furthermore, existing systems for disinfection can not be easily implemented in existing infrastructure, such as in existing buildings like offices, reception areas, etc., and / or can not easily be able to serve larger spaces. This can again increase the risk of contamination. Furthermore, incorporation in an HVAC system can not yield the desired effect, and can appear relatively complex. Furthermore, existing systems can not be energy efficient, or can be relatively bulky, and can also not easily be incorporated in functional devices, e.g. such as luminaires.

[0008] Other disinfection systems can use one or more antimicrobial and / or antiviral means to disinfect a space or object. Examples of such means can be chemical agents that can cause concern. For example, chemical agents can also be harmful to humans and pets.

[0009] In embodiments, the disinfecting light can in particular comprise ultraviolet (UV) radiation (and / or optionally violet radiation), i.e. the light can comprise wavelengths selected from the ultraviolet wavelength range (and / or optionally the violet wavelength range). However, other wavelengths are not excluded herein. The ultraviolet wavelength range is defined as light with a wavelength range of 100 nm to 380 nm, and can be divided into different types of UV light / UV wavelength ranges (Table 1). Different UV wavelengths of radiation can have different properties, and thus can have different compatibility with humans present, and can have different effects when used for disinfection (Table 1).

[0010] Table 1: Properties of different types of UV, violet and NIR wavelength light

[0011]

[0012] Each UV type / wavelength range can have different advantages and / or disadvantages. Relevant aspects can be (relative) sterilization effectiveness, safety (with respect to the radiation), and ozone generation (due to its radiation). Depending on the application, a particular type of UV light or a particular combination of UV light types can be selected, and provide performance over other types of UV light. UV-A can be (relatively) safe, and can inactivate (kill) bacteria, but can be less effective in inactivating (killing) viruses. UV-B can be (relatively) safe, can inactivate (kill) bacteria, and can be moderately effective in inactivating (killing) viruses when using low doses (i.e. low exposure times and / or low intensities). UV-B can also have the additional advantage that it can be effectively used to generate vitamin D in the skin of humans or animals. Near UV-C can be relatively unsafe, but can be effective in inactivating, in particular killing, bacteria and viruses. Far UV-C can also be effective in inactivating (killing) bacteria and viruses, but can be (comparatively) safe relative to other UV-C wavelength ranges. Far UV light can generate some ozone, which can be harmful to humans and animals. Extreme UV-C can also be effective in inactivating (killing) bacteria and viruses, but can be relatively unsafe. Extreme UV-C can generate ozone, which can be undesirable when exposed to humans or animals. In certain applications, ozone can be desired and can aid in disinfection, but can need to be shielded from humans and animals. Thus, in the table, a “+” for ozone generation in particular means that ozone is generated, which can be useful for disinfection applications, but can be harmful when humans / animals are exposed to the ozone. Thus, in many applications, this “+” can actually be undesirable, while in other applications it can be desired. In embodiments, the types of light indicated in the above table can be used for disinfecting air and / or surfaces.

[0013] The terms “inactivation” and “killing” in relation to viruses can in this document in particular refer to the destruction of viruses in such a way that they can no longer infect and / or propagate in host cells, i.e. viruses can be (substantially) harmless after inactivation or killing.

[0014] As pointed out by M. McLean et al. in Journal of Hospital Infection, Volume 88, Issue 1, September 2014, Pages 1-11, https: / / doi.org / 10.1016 / j.jhin.2014.06.004 (incorporated herein by reference), violet-blue light (in particular light of 405 nm) has significant antibacterial properties against a wide range of bacterial and fungal pathogens. Furthermore, R. Rathnasinghe et al. in Scientific Reports https: / / doi:10.1038 / s41598-021-97797-0, and / or doi: https: / / doi.org / 10.1101 / 2021.03.14.435337 seem to demonstrate increased susceptibility of important lipid-enveloped respiratory pathogens (such as SARS-CoV-2 (the pathogen of COVID-19) and influenza A virus) to 405 nm visible light in the absence of exogenous photosensitizers, which indicates a potential non-porphyrin-dependent alternative mechanism of visible light-mediated viral inactivation.

[0015] The application of such light can not be simple, as it can undesirably alter the spectral properties of the light, and can not be attractive to people or have other undesirable effects, e.g. the environment of work or relaxation is unpleasant.

[0016] It is therefore an aspect of the present invention to provide an alternative light generating system that preferably further at least partially obviates one or more of above- described drawbacks. It can be an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0017] According to a first aspect, the present invention provides a light generating system configured to generate system light. In particular, the light generating system comprises a first light generating device. In embodiments, the first light generating device can comprise a first light source and a first luminescent converter. In particular, the first light source can comprise a solid state light source. In particular embodiments, the first light source can be configured to generate first light source light having a first light source centroid wavelength (l s,1), the first light source centroid wavelength is in particular selected from the range of 380-430 nm, more in particular from the range of 380-420 nm. Further, in embodiments, the first luminescence converter can be configured to convert at least part of the first light source light into first converter light. The first converter light can in particular have a first converter centroid wavelength (λ c,1 ) selected from the green-yellow wavelength range. In particular, the first light generating device can be configured to generate first device light comprising the first light source light and the first converter light. In particular, the first light generating device can be configured to generate first device light having a spectral power distribution in the wavelength range of 380-780 nm of which at least 60% of the spectral power is provided by the first light source light and at most 40% of the spectral power is provided by the first converter light. Hence, in particular, the present invention provides, in embodiments, a light generating system configured to generate system light, wherein the light generating system comprises a first light generating device, wherein: (A) the first light generating device comprises a first light source and a first luminescence converter; (B) the first light source comprises a solid state light source, wherein the first light source is configured to generate first light source light having a first light source centroid wavelength (λ s,1 ) selected from the range of 380-430 nm, more in particular from the range of 380-420 nm; (C) the first luminescence converter is configured to convert at least part of the first light source light into first converter light having a first converter centroid wavelength (λ c,1 ) selected from the green-yellow wavelength range; and (E) the first light generating device is configured to generate first device light comprising the first light source light and the first converter light, more in particular configured to generate first device light having a spectral power distribution in the wavelength range of 380-780 nm of which at least 60% of the spectral power is provided by the first light source light and at most 40% of the spectral power is provided by the first converter light. In particular embodiments, the first light generating device can be combined with a second light generating device different from the first light generating device and configured to generate (in an operational mode) white system light (see also below).

[0018] With such a system, it is possible to provide light, such as white or whitish (system) light, which has an effect of reducing viral and / or bacterial load due to the short-wavelength radiation of the first light generating device. Moreover, it appears that the efficiency and / or efficacy is increased due to the presence of the luminescent material of the first light generating device. With such a system, it is also possible to provide light for specific purposes, like general illumination, accent lighting, wall washing, etc., while, or alternatively, it is possible to provide light which can reduce viral and / or bacterial load. Moreover, in embodiments, due to the addition of (white type) light via the first light generating device to the white light of the second light generating device (see also below), it is possible to provide white (system) light with an additional effect, i.e. a reduction of viral and / or bacterial load. Moreover, with the present system, it is possible to provide functional light with a higher efficiency than providing short-wavelength radiation only. Hence, the present application can also provide a system which is capable of providing white light with a color point close to the black body locus and with a significant reduction of viral and / or bacterial load.

[0019] As indicated above, the light generating system can in particular be configured to generate system light. In embodiments, in an operational mode, the system light can comprise the first device light. In other operational modes, if any, the system light can also comprise other light, if the system comprises one or more other types of light generating devices (see also embodiments below).

[0020] The first light generating device can comprise one or more first light sources. The one or more light sources can be configured to generate first light source light.

[0021] The term "light source" can in principle relate to any light source known in the art. It can be a conventional (tungsten) bulb, a low-pressure mercury lamp, a high-pressure mercury lamp, a fluorescent lamp, an LED (light-emitting diode). In particular embodiments, the light source comprises a solid state LED light source, such as an LED or a laser diode (or "diode laser"). The term "light source" can also relate to a plurality of light sources, such as 2-200 (solid state) LED light sources. Hence, the term LED can also refer to a plurality of LEDs. Moreover, the term "light source" can in embodiments also refer to a so-called Chip On Board (COB) light source. The term "COB" in particular refers to an LED chip in the form of a semiconductor chip which is neither encapsulated nor connected, but is mounted directly onto a substrate, such as a PCB. Hence, a plurality of light-emitting semiconductor light sources can be configured on the same substrate. In embodiments, the COB is a multi-LED chip which is configured together as a single lighting module.

[0022] The light source can have a light exit surface. With reference to a conventional light source such as a light bulb or a fluorescent lamp, this can be the outer surface of the glass or quartz envelope. With an LED, this can for example be the LED die, or the outer surface of the resin when resin is applied to the LED die. In principle, it can also be the end of an optical fiber. The term exit surface particularly relates to the part of the light source where light actually leaves or escapes from the light source. The light source is configured to provide a light beam. This light beam (thus) escapes from the light exit surface of the light source.

[0023] Similarly, the light generating device can comprise a light exit surface, such as an end window. Also, similarly, the light generating system can comprise a light exit surface, such as an end window.

[0024] The term "light source" can refer to a semiconductor light emitting device such as a light emitting diode (LED), a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSEL), an edge emitting laser, etc. The term "light source" can also refer to an organic light emitting diode (OLED), such as a passive-matrix (PMOLED) or active-matrix (AMOLED). In a particular embodiment, the light source comprises a solid state light source such as an LED or laser diode. In one embodiment, the light source comprises an LED (light emitting diode). The term "light source" or "solid state light source" can also refer to a superluminescent diode (SLED). The term LED can also refer to a plurality of LEDs.

[0025] The term "light source" can also relate to a plurality of (essentially identical (or different)) light sources, such as 2-2000 solid state light sources. In an embodiment, the light source can comprise one or more micro-optical elements (array of micro-lenses) downstream of a single solid state light source such as an LED or downstream of a plurality of solid state light sources (i.e. shared by a plurality of LEDs). In an embodiment, the light source can comprise an LED with on-chip optics. In an embodiment, the light source comprises a pixelated single LED (with or without optics) (providing on-chip light beam steering in an embodiment).

[0026] In an embodiment, the light source can be configured to provide primary radiation (which is used as such), for example such as a blue light source (like a blue LED), or a green light source (such as a green LED), and a red light source (such as a red LED). Such LEDs, which can not comprise luminescent material ("phosphor"), can be indicated as direct color LEDs.

[0027] However, in other embodiments the light source can be configured to provide primary radiation, and part of the primary radiation is converted to secondary radiation. The secondary radiation can be conversion based on a luminescent material. The secondary radiation can thus also be indicated as luminescent material radiation. In embodiments, the luminescent material can be comprised by the light source, such as a LED with a luminescent material layer or a LED with a dome comprising a luminescent material. Such a LED can be indicated as phosphor converted LED or PC LED. In other embodiments, the luminescent material can be configured at a distance from the light source ("remote"), such as a LED with a luminescent material layer not in physical contact with the die of the LED. Thus, in particular embodiments the light source can be a light source that emits at least light selected from the wavelength range of 380-470 nm during operation. However, other wavelengths are also possible. This light can be partly used by the luminescent material.

[0028] In embodiments, the light generating device can comprise a luminescent material. In embodiments, the light generating device can comprise a PC LED. In other embodiments, the light generating device can comprise a direct LED (i.e. no phosphor). In embodiments, the light generating device can comprise a laser device, like a laser diode. In embodiments, the light generating device can comprise a superluminescent diode. Thus, in particular embodiments the light source can be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source can comprise a LED.

[0029] The light source can in particular be configured to generate light source light having an optical axis (O), a (beam shape), and a spectral power distribution. In embodiments, the light source light can comprise one or more bands having a bandwidth known for laser light.

[0030] The term "light source" (thus) can refer to the light generating element (e.g. like a solid state light source) itself, or for example to the package of the light generating element (such as a solid state light source), as well as one or more of a luminescent material containing element and (other) optical means (like a lens, a collimator). A light converter element ("converter element" or "converter") can comprise a luminescent material containing element. For example, a solid state light source itself (like a blue LED) is a light source. A combination of a solid state light source (as light generating element) and a light converter element (such as a blue LED and a light converter element optically coupled to the solid state light source), can also be a light source (but can also be indicated as a light generating device). Thus, a white LED is a light source (but can also for example be indicated as a (white) light generating device).

[0031] The term "light source" herein can also refer to a light source comprising a solid state light source, such as a LED or a laser diode or a superluminescent diode.

[0032] Hence, in an embodiment, the term "light source" can also refer to a light source that is (also) based on light conversion, such as a light source combined with a luminescent converter material. As such, the term "light source" can also refer to a combination of an LED and a luminescent material configured to convert at least a part of the LED radiation, or to a combination of a (diode) laser and a luminescent material configured to convert at least a part of the (diode) laser radiation.

[0033] In an embodiment, the term "light source" can also refer to a combination of a light source, such as an LED, and a light filter that can alter the spectral power distribution of the light generated by the light source. In particular, the term "light generating device" can be used to address a light source and a further (optical component), such as a light filter and / or a beam-shaping element, etc.

[0034] The phrase "different light sources" or "a plurality of different light sources" and similar phrases can in an embodiment refer to a plurality of solid state light sources selected from at least two different bins. Similarly, the phrase "same light sources" or "a plurality of same light sources" and similar phrases can in an embodiment refer to a plurality of solid state light sources selected from the same bin.

[0035] The term "solid state light source" or "solid state material light source" and similar terms can in particular refer to a semiconductor light source, such as a light emitting diode (LED), a diode laser, or a superluminescent diode.

[0036] In particular, the term "light generating device" can refer to a device comprising a solid state light source, such as a light emitting diode (LED).

[0037] As indicated above, the light generating system can comprise a first light generating device. The term "first light generating device" can also refer to a plurality of first light generating devices, two or more of which can be identical, and / or two or more of which can be different. In particular, the first light generating device can comprise a first light source and a first luminescent converter.

[0038] In an embodiment, the first light source can comprise a solid state light source. Further, as indicated above, the term "first light source" can also refer to a plurality of first light sources, two or more of which can be identical, and / or two or more of which can be different. In particular, the first light source can comprise a solid state light source, such as a laser diode or an LED, in particular an LED. In particular, when there is more than one first light source, the first light sources can belong to the same bin.

[0039] In embodiments, the first light source can be configured to generate first light source light having a wavelength selected from the 380-430 nm, more particularly 380-420 nm wavelength range, more particularly selected from the 395-415 nm range, even more particularly selected from the 400-410 nm range. More particularly, the first light source can be configured to generate first light source light having a peak wavelength selected from the 380-430 nm wavelength range, more particularly the 380-420 nm range, such as in embodiments 395-415 nm, even more particularly selected from the 400-410 nm range.

[0040] However, in embodiments, the first light source can be configured to generate first light source light having a first light source centroid wavelength (λ s,1 ) selected from the 380-430 nm, more particularly 380-420 nm range. With such light, viral load and / or bacterial load can be reduced. More particularly, the first light source centroid wavelength (λ s,1 ) can be selected from the 395-415 nm range. In particular, a wavelength around 405 nm can be appropriate. Thus, in further particular embodiments, the first light source centroid wavelength (λ s,1 ) can be selected from the 400-410 nm range.

[0041] The term “centroid wavelength” (also indicated as λc) is known in the art and refers to the wavelength value at which half of the light energy is at a shorter wavelength and half of the energy is at a longer wavelength; the value is in nanometers (nm). It is this wavelength that divides the integral of the spectral power distribution into two equal parts, as expressed by the formula λc =∑λ*I(λ) / (∑I(λ)), where the summation is over the wavelength range of interest, I(λ) is the spectral energy density (i.e., the integral of intensity over wavelength and emission band, normalized to the integrated intensity). The centroid wavelength can be determined, for example, under operating conditions.

[0042] As indicated, with such light, some bacteria and / or some viruses can be inactivated. However, the efficacy of such a first light generating device can be relatively low due to the short wavelength, while the eye is more sensitive to green. Moreover, it appears that the coupling out of the first light source light via the light-transmissive material can be lower than desired. Embedding some (first) luminescent material in the light-transmissive material provides for a better coupling out. It appears that a relatively low amount and a relatively low conversion can already have the desired effect. Thus, with a relatively low conversion, leaving a substantial contribution of the original short wavelength radiation, a type of white light can be generated that can (however) have useful properties for reducing viral load and / or bacterial load.

[0043] Hence, the first light generating device can comprise a (first) luminescent material. In embodiments, the first converter light can be provided substantially by the first luminescent material. The first converter can comprise one or more (first) luminescent materials.

[0044] In the following, some embodiments related to luminescent materials are described, which can relate to the first luminescent material (of the first light generating device) and / or the second luminescent material (of the optional second light generating device).

[0045] The term luminescent material particularly refers to a material that can convert a first radiation, particularly one or more of UV radiation and blue radiation, into a second radiation. Typically, the first and second radiation have different spectral power distributions. Hence, instead of the term luminescent material, also the term luminescent converter or converter can be applied. Typically, the second radiation has a spectral power distribution at a larger wavelength than the first radiation, which is the case in so-called down-conversion. However, in particular embodiments, the second radiation has a spectral power distribution with intensity at a smaller wavelength than the first radiation, which is the case in so-called up-conversion.

[0046] In embodiments, the luminescent material can particularly refer to a material that can convert radiation into e.g. visible light and / or infrared light. For example, in embodiments, the luminescent material can be capable of converting one or more of UV radiation and blue radiation into visible light. In particular embodiments, the luminescent material can also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material emits radiation. Typically, the luminescent material will be a down-converter, i.e. a smaller wavelength of radiation is converted into radiation having a larger wavelength (λ ex <λ em ), but in particular embodiments, the luminescent material can comprise an up-converter luminescent material, i.e. a larger wavelength of radiation is converted into radiation having a smaller wavelength (λ ex >λ em ).

[0047] In embodiments, the term luminescence can refer to phosphorescence. In embodiments, the term luminescence can also refer to fluorescence. Instead of the term luminescence, also the term emission can be applied. Hence, the terms first radiation and second radiation can refer to excitation radiation and emission (radiation), respectively. Similarly, the term luminescent material can in embodiments refer to phosphorescence and / or fluorescence.

[0048] The term luminescent material can also refer to a plurality of different luminescent materials. Examples of possible luminescent materials are indicated below. Hence, the term luminescent material can in particular embodiments also refer to a luminescent material compound.

[0049] In the embodiments, the luminescent material is selected from garnet and nitrides, particularly doped with trivalent cerium or divalent europium, respectively. The term "nitride" may also refer to oxynitrides or nitrogen silicates, etc. Alternatively or additionally, the luminescent material may be selected from silicates, particularly doped with divalent europium.

[0050] In a particular embodiment, the luminescent material includes A3B5O. 12 Ce-type luminescent materials, wherein A in embodiments comprises one or more of Y, La, Gd, Tb, and Lu, particularly at least one or more of Y, Gd, Tb, and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In, and Sc. Specifically, A may comprise one or more of Y, Gd, and Lu, such as one or more of Y and Lu. Specifically, B may comprise one or more of Al and Ga, more particularly at least Al, such as substantially all Al. Therefore, particularly suitable luminescent materials are garnet materials comprising cerium. Examples of garnet particularly include A3B5O. 12 Garnet, wherein A comprises at least yttrium or lutetium, and wherein B comprises at least aluminum. This garnet may be doped with cerium (Ce), praseodymium (Pr), or a combination of cerium and praseodymium; however, it is particularly doped with Ce. Specifically, B may comprise aluminum (Al), however, in addition to aluminum, B may also partially comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), particularly up to about 20% of B, more particularly up to about 10% of B (i.e., the B ion is essentially composed of more than 90% molar Al and less than 10% molar Ga, Sc, and In); B may particularly comprise up to about 10% gallium. In another variant, B and O may be at least partially replaced by Si and N. Element A may particularly be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb), and lutetium (Lu). Furthermore, the presence of Gd and / or Tb is particularly only up to about 20% of A. In a particular embodiment, the garnet luminescent material includes (Y 1-x Lu x )3B5O 12 :Ce, where x is equal to or greater than 0 and equal to or less than 1. The term ":Ce" indicates that a portion of the metal ions in a luminescent material (i.e., in garnet, a portion of the "A" ions) is replaced by Ce. For example, in (Y 1-x Lu x )3Al5O 12 In the case of Ce, a portion of Y and / or Lu is replaced by Ce. This is known to those skilled in the art. Ce will generally replace no more than 10% of A; typically, the Ce concentration will be in the range of 0.1% to 4%, particularly 0.1% to 2% (relative to A). Assuming 1% Ce and 10% Y, the perfectly correct chemical formula could be (Y0.1 Lu 0.89 Ce 0.01 )3Al5O 12 . As known to the skilled person, Ce in garnets is essentially or only in the trivalent state.

[0051] In embodiments, the luminescent material (thus) comprises A3B5O 12 , wherein in particular embodiments at most 10% of B-O can be replaced by Si-N.

[0052] In particular embodiments, the luminescent material comprises (Y x1-x2-x3 A’ x2 Ce x3 )3(Al y1-y2 B’ y2 )5O 12 , wherein x1+x2+x3=1, wherein x3>0, wherein 0

[0053] In particular embodiments, at most 10% of B-O can be replaced by Si-N. Here, B in B-O refers to one or more of Al, Ga, In and Sc (and O refers to oxygen); in particular embodiments, B-O can refer to Al-O. As indicated above, in particular embodiments x3may be selected from the range 0.001-0.04. In particular, such luminescent material can have a proper spectral distribution (see however below), have a relatively high efficiency, have a relatively high thermal stability, and allow for a high CRI (optionally in combination with light of other light sources, as described herein). Thus, in particular embodiments A can be selected from the group consisting of Lu and Gd. Alternatively or additionally, B can comprise Ga. Thus, in embodiments, the luminescent material comprises (Y x1-x2-x3 (Lu,Gd) x2 Ce x3 )3(Al y1-y2 Ga y2 )5O 12wherein Lu and / or Gd can be available. Even more particularly, x3 is selected from the range 0.001 - 0.1, wherein 0 < x2+x3 < 0.1, and wherein 0 < y2 < 0.1. Further, in particular embodiments, at most 1% of B-O can be replaced by Si-N. Here, the percentages refer to molar (as known in the art); see also e.g. EP3149108. In yet further particular embodiments, the luminescent material comprises (Y x1-x3 Ce x3 )3Al5O 12 wherein x1+x3 = 1, and wherein 0 < x3 < 0.2, such as 0.001 - 0.1.

[0054] In particular embodiments, the light generating device can comprise only luminescent material of the type comprising cerium containing garnets. In further particular embodiments, the light generating device comprises a single type of luminescent material, such as (Y x1-x2-x3 A’ x2 Ce x3 )3(Al y1-y2 B’ y2 )5O 12 Thus, in particular embodiments, the light generating device comprises luminescent material, wherein at least 85% by weight, even more particularly at least about 90% by weight, such as yet even more particularly at least about 95% by weight of the luminescent material comprises (Y x1-x2-x3 A’ x2 Ce x3 )3(Al y1-y2 B’ y2 )5O 12 Herein, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc, wherein x1+x2+x3 = 1, wherein x3 > 0, wherein 0 < x2+x3 < 0.2, wherein y1+y2 = 1, wherein 0 < y2 < 0.2. In particular, x3 is selected from the range 0.001 - 0.1. Note that in embodiments x2 = 0. Alternatively or additionally, in embodiments y2 = 0.

[0055] In particular embodiments, A can in particular comprise at least Y, and B can in particular comprise at least Al.

[0056] Alternatively or additionally, wherein the luminescent material can comprise A3Si6N 11 :Ce 3+ type of luminescent material, wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y.

[0057] In embodiments, the luminescent material can alternatively or additionally comprise MS:Eu 2+ and / or M2Si5N8:Eu 2+ and / or MAlSiN3:Eu 2+ and / or Ca2AlSi3O2N5:Eu 2+ one or more of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2Si5N8:Eu. In these compounds, europium (Eu) is essentially or only divalent and replaces one or more of the indicated divalent cations. Generally, Eu is not present in an amount larger than 10% of the cations; its presence will in particular be in the range of about 0.5% to 10%, more particularly in the range of about 0.5% to 5%, relative to the cations it replaces. The term ":Eu" indicates that a part of the metal ions is replaced by Eu (in these examples, by Eu 2+ ). For example, assuming 2% Eu in CaAlSiN3:Eu, the correct chemical formula can be (Ca 0.98 Eu 0.02 )AlSiN3. The divalent europium will generally replace a divalent cation, such as the above-mentioned divalent alkaline earth metal cations, in particular Ca, Sr or Ba. The material (Ba,Sr,Ca)S:Eu can also be indicated as MS:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); in particular, M comprises calcium or strontium, or calcium and strontium, in this compound, more particularly calcium. Here, Eu is introduced and replaces at least a part of M (i.e. one or more of Ba, Sr and Ca). Further, the material (Ba,Sr,Ca)2Si5N8:Eu can also be indicated as M2Si5N8:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); in particular, M comprises Sr and / or Ba in this compound. In further particular embodiments, M consists of Sr and / or Ba (not taking into account the presence of Eu), in particular 50% to 100% Ba, more particularly 50% to 90% Ba, and 50% to 0% Sr, in particular 50% to 10% Sr, such as Ba 1.5 Sr 0.5Si5N8:Eu (i.e., 75% Ba; 25% Sr). Here, Eu is introduced and replaces at least a portion of M (i.e., one or more of Ba, Sr, and Ca). Similarly, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSiN3:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca); in particular, M includes calcium or strontium, or calcium and strontium, in the compound, more particularly calcium. Here, Eu is introduced and replaces at least a portion of M (i.e., one or more of Ba, Sr, and Ca). The Eu in the above indicated luminescent materials is substantially or only in the divalent state, as known to those skilled in the art.

[0058] In embodiments, the red luminescent material can include one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu, and (Ba,Sr,Ca)2Si5N8:Eu. In these compounds, europium (Eu) is substantially or only divalent and replaces one or more of the indicated divalent cations. Generally, the amount of Eu present is not greater than 10% of the cations; its presence is particularly in the range of about 0.5% to 10%, more particularly in the range of about 0.5% to 5%, relative to the cations it replaces. The term ":Eu" indicates that a portion of the metal ions is replaced by Eu (in these examples, by Eu 2+ instead). For example, assuming 2% Eu in CaAlSiN3:Eu, the correct chemical formula can be (Ca 0.98 Eu 0.02 )AlSiN3. The divalent europium will generally replace a divalent cation, such as the above-mentioned divalent alkaline earth metal cations, in particular Ca, Sr, or Ba.

[0059] The material (Ba,Sr,Ca)S:Eu can also be indicated as MS:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca); in particular, M includes calcium or strontium, or calcium and strontium, in the compound, more particularly calcium. Here, Eu is introduced and replaces at least a portion of M (i.e., one or more of Ba, Sr, and Ca).

[0060] Further, the material (Ba,Sr,Ca)2Si5N8:Eu can also be indicated as M2Si5N8:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); in particular, M comprises Sr and / or Ba in this compound. In further particular embodiments, M consists of Sr and / or Ba (not considering the presence of Eu), in particular 50% to 100% of Ba, more particularly 50% to 90% of Ba, and 50% to 0% of Sr, in particular 50% to 10% of Sr, such as Ba 1.5 Sr 0.5 Si5N8:Eu (i.e. 75% of Ba; 25% of Sr). Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr and Ca).

[0061] Similarly, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSiN3:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); in particular, M comprises calcium or strontium, or calcium and strontium, more particularly calcium, in this compound. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr and Ca).

[0062] As known to the person skilled in the art, Eu in the above indicated luminescent materials is essentially or only in the divalent state.

[0063] The blue luminescent material can comprise YSO (Y2Si05:Ce 3+ ) or similar compounds, or BAM (BaMgAl 10 O 17 :Eu 2+ ) or similar compounds.

[0064] The term “luminescent material” herein particularly relates to inorganic luminescent materials.

[0065] The term “phosphor” also stands for the term “luminescent material”. These terms are known to the person skilled in the art.

[0066] Alternatively or additionally, other luminescent materials can also be applied. For example, quantum dots and / or organic dyes can be applied and can optionally be embedded in a transmissive matrix or the like, such as e.g. a polymer, such as PMMA or a polysiloxane or the like.

[0067] Quantum dots are small crystals of semiconductor material, typically having a width or diameter of only a few nanometers. When excited by incident light, quantum dots emit light whose color is determined by the size and material of the crystal. It is thus possible to produce light of a specific color by adjusting the size of the dots. 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 zinc sulfide (ZnS). Quantum dots without cadmium can also be used such as indium phosphide (InP) and copper indium sulfide (CuInS2) and / or indium silver sulfide (AgInS2). Quantum dots show very narrow emission bands and thus they show saturated colors. Furthermore, the emission color can be easily tuned by adjusting the size of the quantum dots. Any type of quantum dot known in the art can be used in the present invention. However, for environmental safety and concern reasons, it can be preferred to use quantum dots without cadmium or at least with a very low cadmium content.

[0068] Instead of or in addition to quantum dots, other quantum confinement structures can also be used. In the context of the present application, the term "quantum confinement structure" is to be understood as e.g. quantum well, quantum dot, quantum rod, tripod, tetrapod or nanowire, etc.

[0069] Organic phosphors can also be used. An example of a suitable organic phosphor material is an organic luminescent material based on a perylene derivative, for example the compound sold by BASF under the name Lumation® F Yellow- 171. Examples of suitable compounds include, but are not limited to Lumation® Red F305, Lumation® Orange F240, Lumation® Yellow F083 and Lumation® F 170. Red F305, Orange F240, Yellow F083 and F 170.

[0070] The different luminescent materials can have different spectral power distributions of the respective luminescent material light. Alternatively or additionally, such different luminescent materials can in particular have different color points (or dominant wavelengths).

[0071] As mentioned above, other luminescent materials are also possible. Thus, in particular embodiments, the luminescent material is selected from the group consisting of nitrides comprising divalent europium, oxonitrides comprising divalent europium, silicates comprising divalent europium, garnets comprising cerium and quantum structures. The quantum structures may, for example, comprise quantum dots or quantum rods (or other quantum type particles) (see above). The quantum structures can also comprise quantum wells. The quantum structures can also comprise photonic crystals.

[0072] In particular, the first luminescent material can provide a broadband emission.

[0073] ​The luminescent material can be chosen so as to obtain an emission band with a full width at half maximum of (the luminescent material light) at least 40 nm, such as at least 50 nm. For example, the luminescent material can be chosen so as to obtain an emission band with a full width at half maximum of at least 60 nm. This can be the case, for example, for a garnet luminescent material comprising trivalent cerium (as described herein). Hence, in particular, the luminescent material can comprise a broadband emitter. The luminescent material can further comprise a plurality of broadband emitters. In particular, when two or more luminescent materials are applied to convert at least a part of the first device light and / or at least a part of the second device light, at least two of the two or more luminescent materials can be configured to provide a respective luminescent material light having an emission band comprising a full width at half maximum of (the luminescent material light) at least 40 nm, such as at least 50 nm.

[0074] In a particular embodiment, the first luminescent converter can be configured to convert (at least) a part of the first light source light into first converter light. Further, in embodiments, the first converter light can have a first converter centroid wavelength (λ c,1 ). In particular, the first converter centroid wavelength (λ c,1 ) is selected from the green-yellow wavelength range. Hence, the first converter centroid wavelength (λ c,1 ) can be in the wavelength range of 490-590 nm, in particular at least 500 nm, and in particular at most about 580 nm.

[0075] The terms "violet light" or "violet emission" and like terms specifically relate to light having a wavelength in the range of about 380 nm - 440 nm. In particular embodiments, violet light can have a centroid wavelength in the range of 380 nm - 440 nm. The terms "blue light" or "blue emission" and like terms specifically relate to light having a wavelength in the range of about 440 nm - 490 nm (including some violet and cyan hues). In particular embodiments, blue light can have a centroid wavelength in the range of 440 nm - 490 nm. The terms "green light" or "green emission" and like terms specifically relate to light having a wavelength in the range of about 490 nm - 560 nm. In particular embodiments, green light can have a centroid wavelength in the range of 490 nm - 560 nm. The terms "yellow light" or "yellow emission" and like terms specifically relate to light having a wavelength in the range of about 560 nm - 590 nm. In particular embodiments, yellow light can have a centroid wavelength in the range of 560 nm - 590 nm. The terms "orange light" or "orange emission" and like terms specifically relate to light having a wavelength in the range of about 590 nm - 620 nm. In particular embodiments, orange light can have a centroid wavelength in the range of 590 nm - 620 nm. The terms "red light" or "red emission" and like terms specifically relate to light having a wavelength in the range of about 620 nm - 750 nm. In particular embodiments, red light can have a centroid wavelength in the range of 620 nm - 750 nm. The terms "cyan light" or "cyan emission" and like terms specifically relate to light having a wavelength in the range of about 490 nm - 520 nm. In particular embodiments, cyan light can have a centroid wavelength in the range of 490 nm - 520 nm. The terms "amber light" or "amber emission" and like terms specifically relate to light having a wavelength in the range of about 585 nm - 605 nm (such as about 590 nm - 600 nm). In particular embodiments, amber light can have a centroid wavelength in the range of 585 nm - 605 nm.

[0076] In this way, the first light generating device can specifically be configured to generate first device light comprising first light source light and first converter light. Specifically, the first device light can essentially consist of the first light source light and the first converter light, wherein the latter is essentially generated by the one or more first (solid state) light sources, and wherein the latter is generated by converting a portion of the first light source light into the first converter light. In particular embodiments, at least 60% of the spectral power can be provided by the first light source light and at most 40% of the spectral power can be provided by the first converter light, relative to the spectral power distribution of the first device light in the range of 380 nm - 780 nm.

[0077] In particular embodiments, the first luminescence converter can comprise a first host material and a first luminescent material. Examples of the first luminescent material are given above and below, with particular attention to those that can provide substantially green and / or yellow light. Thus, in embodiments, the first luminescence converter can be configured to convert the first light source light into first converter light having a first converter centroid wavelength (λ c,1 ) selected from the yellow-green wavelength range, even more particularly from the green wavelength range.

[0078] In particular embodiments, at most 20% of the spectral power of the first converter light in the 380-780 nm range can be in the 585-780 nm range. Thus, the intensity in the orange-red wavelength range of the spectral power distribution of the first converter light can be relatively low. Thus, the first converter light can have a spectral power distribution in the 380-780 nm wavelength range, with at most 20% of the spectral power in this wavelength range being in the 585-780 nm wavelength range.

[0079] The host material can in particular comprise a resin, such as a silicone.

[0080] In particular embodiments, the first luminescent material has a first weight percentage CW1 relative to the total weight of the first luminescence converter. In embodiments, CW1 < 10 wt.%, such as selected from the range of about 0.1-10 wt.%, such as from the range of about 0.5-8 wt.%.

[0081] In particular embodiments, the first luminescent material has a first volume percentage CV1 relative to the total volume of the first luminescence converter. In embodiments, CV1 < 3 vol.%, such as selected from the range of about 0.03-3 vol.%, such as from the range of about 0.15-2.5 vol.%.

[0082] In embodiments, the first device light can have a relatively high correlated color temperature (CCT). In particular, the CCT of the first device light can in embodiments be at least about 5500 K, such as at least 6000 K. In particular embodiments, the first device light can have a correlated color temperature selected from the range of 6000-25000 K. In particular embodiments, the first device light can have a correlated color temperature selected from the range of at least about 6500 K. The first device light can be a relatively cool white light or a cool white light. In particular embodiments, the first device light can have a color point selected from within 0-20 SDCM from the black body locus (BBL), such as within about 15 SDCM from the BBL, such as within about 10 SDCM. Thus, the first device light can be white-emitting.

[0083] However, in other embodiments, the first device light can also substantially deviate from the BBL, such as having a color point which is (substantially) more than 20 SDCM from the BBL.

[0084] In embodiments, the first device light can have a color point with u' selected from the range of 0.10-0.22, and with v' selected from the range of 0.25-0.55. More particularly, in specific embodiments, the first device light can have a color point with u' selected from the range of 0.12-0.22, such as 0.12-0.20, and v' selected from the range of 0.30-0.50. In such embodiments, the first device light can be relatively deviating from the BBL. In combination with the second device light, a color point can be generated which is white and within 0 SDCM - 20 SDCM from the black body locus (BBL), such as within about 15 SDCM from the BBL, like within about 10 SDCM from the BBL.

[0085] In embodiments, the first device light can have a color which can be blue or cyan-like.

[0086] In specific embodiments, the first converter light can have a first spectral power distribution in the 380-780 nm wavelength range, with at most 15%, such as at most 10%, of its spectral power in the 380-490 nm wavelength range. Hence, the first luminescent material can have substantially no blue emission (and in specific embodiments, is substantially green and / or yellow).

[0087] The term white light and similar terms herein are known to the person skilled in the art. It particularly relates to light having a correlated color temperature (CCT) between about 1800 K and 20000 K, such as at least about 2000 K, particularly in the range of 2700 K - 20000 K, for general lighting, particularly in the range of about 2000 K - 6700 K, such as 2700 K - 6500 K, and for backlighting purposes, particularly in the range of about 6500 K and 20000 K, and particularly within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), particularly within 10 SDCM from the BBL, even more particularly within about 5 SDCM from the BBL.

[0088] In embodiments, the first device light can have a color rendering index of at most about 80, such as at most about 70, such as even lower, like at most about 60. In embodiments, the first device light can even not be white or white-emitting light.

[0089] In particular, the first light generating device can be provided in combination with a second light generating device. The latter can be configured to generate white light, while the function of the former is essentially to provide disinfecting light having a wavelength selected from the range of 380-430 nm, such as 380-425 nm, more in particular 380-420 nm, more in particular selected from the range of 395-415 nm, even more in particular selected from the range of 400-410 nm.

[0090] In a particular embodiment, the first light generating device can be configured to generate first device light having a spectral power distribution in the wavelength range of 380-780 nm, wherein at least 70% of the spectral power is provided by the first light source light and at most 30% of the spectral power is provided by the first converter light. In an embodiment, the spectral power distribution of the first device light can comprise a spectral power provided by the first light source light in the range of 70-90% and a spectral power provided by the first converter light in the range of 10-30%.

[0091] In a particular embodiment, the first light generating device can be configured to generate first device light having a spectral power distribution in the wavelength range of 380-780 nm, wherein at least 70% of the spectral power is provided by the first light source light and at most 30% of the spectral power is provided by the first converter light. More in particular, the first light generating device can be configured to generate first device light having a spectral power distribution in the wavelength range of 380-780 nm, wherein at least 75% of the spectral power is provided by the first light source light and at most 25% of the spectral power is provided by the first converter light. However, in particular, in an embodiment, the first light generating device can be configured to generate first device light having a spectral power distribution in the wavelength range of 380-780 nm, wherein at least 80% of the spectral power is provided by the first light source light and at most 20% of the spectral power is provided by the first converter light.

[0092] In a particular embodiment, the first light generating device can be configured to generate first device light having a spectral power distribution within the 380-780 nm wavelength range, wherein at most 98% of the spectral power is provided by the first light source light and at least 2% of the spectral power is provided by the first converter light. More specifically, the first light generating device can be configured to generate first device light having a spectral power distribution within the 380-780 nm wavelength range, wherein at most 96% of the spectral power is provided by the first light source light and at least 4% of the spectral power is provided by the first converter light. Yet more specifically, in embodiments, the first light generating device can be configured to generate first device light having a spectral power distribution within the 380-780 nm wavelength range, wherein at most 95% of the spectral power is provided by the first light source light and at least 5% of the spectral power is provided by the first converter light.

[0093] The phrase "spectral power distribution within the 380-780 nm wavelength range" and similar phrases herein specifically refer to a spectral power distribution defined within this range. Alternatively, the phrase "spectral power distribution within the visible wavelength range" and similar phrases can apply. In particular embodiments, light having a spectral power distribution in the visible light can also have intensities in the UV or IR. However, in this document, generally only visible light is referred to. Light having visible light intensities can have intensities at one or more wavelengths within the visible wavelength range.

[0094] The terms "visible", "visible light" or "visible emission" and similar terms refer to light having one or more wavelengths in the range of about 380-780 nm. Here, UV can specifically refer to wavelengths selected from the range of 190-380 nm, such as 200-380 nm.

[0095] The terms "light" and "radiation" are used interchangeably herein unless the context clearly dictates otherwise. Hence, the terms "light" and "radiation" can refer to UV radiation, visible light and IR radiation. In particular embodiments, especially for lighting applications, the terms "light" and "radiation" refer to (at least) visible light.

[0096] The first light generating device can be provided as an LED package.

[0097] As indicated above, the light generating system can comprise a second light generating device. Further, as indicated above, especially the term "light generating device" can refer to a device comprising a solid state light source, such as a light emitting diode (LED).

[0098] The term "second light generating device" can also refer to a plurality of second light generating devices, two or more of which can be identical, and / or two or more of which can be different. In particular, the second light generating device can comprise a second light source and a second luminescent converter.

[0099] In embodiments, the second light source can comprise a solid state light source. Further, as mentioned above, the term "second light source" can also refer to a plurality of second light sources, two or more of which can be identical, and / or two or more of which can be different. In particular, the second light source comprises a solid state light source, such as a laser diode or an LED, in particular an LED. In particular, when there is more than one second light source, the second light sources can belong to the same bin.

[0100] In embodiments, the second light source can be configured to generate second light source light having a wavelength selected from the 440-490 nm wavelength range, more in particular from the 440-485 nm range, even more in particular from the 445-480 nm range. More in particular, the second light source can be configured to generate second light source light having a peak wavelength selected from the 440-490 nm wavelength range, more in particular from the 440-485 nm range, even more in particular from the 445-480 nm range.

[0101] However, in embodiments, the second light source can be configured to generate second light source light having a second light source centroid wavelength (λ s,1 ) selected from the 440-490 nm range. More in particular, the second light source centroid wavelength (λ s,1 ) can be selected from the 440-485 nm range. In particular, a wavelength around 450-460 nm can be appropriate. Thus, in further particular embodiments, the second light source centroid wavelength (λ s,1 ) can be selected from the 445-480 nm range.

[0102] Thus, in embodiments, the light generating system can further comprise a second light generating device. In particular, the second light generating device can comprise a second light source and a second luminescent converter. In embodiments, the second light source can comprise a solid state light source. In particular, the second light source can be configured to generate second light source light. In further particular embodiments, the second light source light can have a second light source centroid wavelength (λ s,2 ).

[0103] Thus, in particular, in embodiments, λ s,2 ≠ λ s,1 . In particular, in embodiments, λs,2 - λ s,1 > 20 nm, even more particularly λ s,2 - λ s,1 ≥ 30 nm, such as λ s,2 - λ s,1 ≥ 35 nm. In particular, in embodiments, λ s,2 - λ s,1 ≤ 90 nm, such as λ s,2 - λ s,1 ≤ 80 nm, for example, in embodiments, λ s,2 - λ s,1 ≤ 75 nm.

[0104] In particular, the second luminescence converter can be configured to convert at least part of the second light source light into second converter light. In yet further particular embodiments, the second luminescence converter light can have a second converter centroid wavelength (λ c,2 ), the second converter centroid wavelength (λ c,2 ) being selected from the green-red wavelength range, i.e. from the wavelength range of 490 nm - 780 nm (and thus, also including e.g. yellow and orange).

[0105] Hence, the second light generating device can comprise a (second) luminescent material. In embodiments, the second converter light can be substantially provided by the second luminescent material. The second converter can comprise one or more (second) luminescent materials.

[0106] In particular, the second converter can comprise two different luminescent materials, like one luminescent material having a centroid wavelength in the green-yellow wavelength range, and another luminescent material having a centroid wavelength in the orange-red wavelength range.

[0107] In particular, the second luminescent material can provide a broadband emission.

[0108] In this way, the second light generating device can in particular be configured to generate second device light comprising the second light source light and the second converter light. In particular, the second device light can substantially consist of the second light source light and the second converter light, wherein the former is substantially generated by the one or more second (solid state) light sources, and the latter is generated by converting part of the second light source light into the second converter light.

[0109] In embodiments, the second light generating device can be configured to generate second device light having a spectral power distribution in the wavelength range of 380 nm - 780 nm, wherein at least 50% of the spectral power is provided by the second converter light, and at most 50% of the spectral power is provided by the second light source light, more particularly, at least 60% of the spectral power is provided by the second converter light, and at most 40% of the spectral power is provided by the second light source light.

[0110] In a particular embodiment, the second light generating device can be configured to generate second device light having a spectral power distribution in the wavelength range of 380-780 nm, wherein at most 30% of the spectral power is provided by the second light source light and at least 70% of the spectral power is provided by the second converter light. In an embodiment, the spectral power distribution (in the wavelength range of 380-780 nm) of the second device light can comprise a spectral power provided by the second light source light in the range of 10-30% and a spectral power provided by the second converter light in the range of 70-90%.

[0111] Hence, the second device light can essentially consist of the second light source light and the second converter light.

[0112] In particular, in an embodiment, the second luminescent converter can be configured to convert the second light source light into the second converter light having a second converter centroid wavelength (l c,2 ) selected from the green-red wavelength range.

[0113] In a particular embodiment, the second luminescent converter can comprise a second host material and a second luminescent material. Examples of the second luminescent material are given above and below, with particular attention to those that can essentially provide one or more, in particular two or more, of green, yellow, orange and red light. The host material can in particular comprise a resin, such as a silicone.

[0114] In a particular embodiment, the second luminescent material can have a second weight percentage CW2 relative to the total weight of the second luminescent converter. In an embodiment, CW2 > 10 wt.%, such as selected from the range of about 10-70 wt.%, such as at least about 20 wt.%, e.g. selected from the range of about 20-70 wt.%, such as, in a particular embodiment, selected from the range of about 50-70 wt.%.

[0115] In a particular embodiment, the second luminescent material has a second volume percentage CV2 relative to the total volume of the second luminescent converter. In an embodiment, CV2 > 3 vol.%, such as selected from the range of about 3-23 vol.%, such as selected from the range of about 6-20 vol.%.

[0116] In particular, the second light generating device can be configured to generate second device light comprising the second converter light and the second light source light. More in particular, the second device light can be white light.

[0117] It will be clear from the above that, in particular, the first device light has a first device spectral power distribution that is different from a second device spectral power distribution of the second device light. Moreover, they can have different color points, although the color point difference can depend on the desired CCT of the second device light. If the CCT of the second device light is relatively high, the color point difference between the first device light and the second device light can be smaller than when the CCT of the second device light is relatively low.

[0118] In particular embodiments, the color or color point of the first type of light and the second type of light can be different when the respective color points of the first type of light and the second type of light differ by at least 0.01 for u' and / or by at least 0.01 for v', even more particularly by at least 0.02 for u' and / or by at least 0.02 for v'. In yet some more specific embodiments, the respective color points of the first type of light and the second type of light can differ by at least 0.03 for u' and / or by at least 0.03 for v'. Here, u' and v' are the color coordinates of the light in the CIE 1976 UCS (Uniform Chromaticity Scale) diagram.

[0119] In embodiments, the difference between the first device light and the second device light can be at least 0.03 for u' and / or for v', such as at least 0.05 in further particular embodiments.

[0120] In particular embodiments, the second light source centroid wavelength (λ s,2 ) can be selected from the range of 445 nm - 480 nm.

[0121] The second device light can have a lower correlated color temperature (CCT) than the first device light. In particular, in embodiments, the CCT of the second device light can be at most about 6500 K, such as at most 6000 K (although larger is not excluded herein). In particular embodiments, the second device light can have a correlated color temperature selected from the range of 1800 K - 6500 K. In particular embodiments, the second device light can have a correlated color temperature selected from the range of at most about 4500 K, such as from the range of 2000 K - 4500 K, such as from the range of about 2700 K - 4000 K. However, other values are possible as well. The second device light can be a warm white light, although this need not necessarily be the case. In particular embodiments, the second device light can have a color point selected within 0 SDCM - 20 SDCM from the black body locus (BBL), such as within about 15 SDCM from the BBL, such as within about 10 SDCM. In embodiments, the second device light can have a color rendering index of at least 70, such as at least about 75, such as at least about 80, or even at least 85, and in particular embodiments at least about 90.

[0122] Thus, in particular, the second device light can have a correlated color temperature selected from the range of 1800K - 6500K, such as from the range of 2000K - 4500K, and can have a color point (of the second device light) that is within 0 SDCM - 15 SDCM from the black body locus, and can have a color rendering index of at least 70, such as at least about 75, like at least about 80. However, higher values, like at least about 85, are also possible. However, in a particular embodiment, the second device light can have a CRI of at least 90.

[0123] The second light generating device can be provided as an LED package.

[0124] When a host material, such as a resin, is used for the luminescent material, the weight percentage of the first luminescent material in the first luminescent converter can be lower than the weight percentage of the second luminescent material in the second luminescent converter. The contribution of the first converter light in the first device light can be (substantially) lower than the contribution of the second converter light in the second device light. In a particular embodiment, CW1 / CW2 < 0.5, such as more particularly CW1 / CW2 < 0.3.

[0125] With such system light, bacteria and / or viruses can be well inactivated. The reason is that the outcoupling of the first light source light is (relatively) high. Surprisingly, it appears that a relatively small amount of first luminescent material and a relatively low conversion can already have the desired effect. Thus, with a relatively low conversion, this configuration leaves a large contribution of the original short wavelength radiation (380nm - 420nm).

[0126] Further, in embodiments, the first luminescent material can have a first volume percentage CV1 of the first luminescent material in the first luminescent converter, and the second luminescent material can have a second volume percentage CV2 of the second luminescent material in the second luminescent converter. In particular, CV1 / CV2 < 0.5, more particularly CV1 / CV2 < 0.3.

[0127] In embodiments, the first luminescent material can comprise a particulate material. This can be useful for the outcoupling of the first light source light. Further, in embodiments, the first host material can comprise a resin, such as in particular a silicone resin.

[0128] In embodiments, the second luminescent material can comprise a particulate material. The second host material can comprise a resin, in particular a silicone resin. In embodiments, the resins can be the same. In other embodiments, they can be different.

[0129] In particular embodiments, at least 50 wt.% of the first luminescent material has a particle size selected from the range of 1 pm - 20 pm. The particle size can be selected from length, width, height, diameter or spherical equivalent diameter (or equivalent spherical diameter). The equivalent spherical diameter (or ESD) of an (irregularly) shaped object is the diameter of a sphere of equivalent volume. Thus, the equivalent spherical diameter (ESD) of a cube with edge length a is Without changing the volume, if a sphere with diameter D in the xyz coordinate system is distorted into any other shape (in the xyz plane), the equivalent sphere diameter of this shape will be D.

[0130] The particle size can be determined using methods known in the art, such as one or more of optical microscopy, SEM (scanning electron microscopy) and TEM (transmission electron microscopy). As known in the art, the size can be number averaged. Thus, the particles can be substantially identical, but the particles can also differ from each other, such as two or more subsets of particles differing from each other, wherein in a subset the particles are substantially identical. The particles can have a unimodal particle size distribution or a multimodal size distribution. In further embodiments, the d50 value of the first luminescent material can be selected from the range of 1 pm - 20 pm. The d50 value can be determined using methods known in the art, such as laser diffraction for luminescent materials of a luminescence converter.

[0131] In particular embodiments, at least 50 wt.% of the second luminescent material can have a particle size selected from the range of 1 pm - 20 pm. The particle size can be selected from length, width, height, diameter or spherical equivalent diameter (or equivalent spherical diameter). In further embodiments, the d50 value of the second luminescent material can be selected from the range of 1 pm - 20 pm.

[0132] In embodiments, the first luminescent material can comprise a Eu 2+ based luminescent material. Such luminescent material can have a better absorption in the low wavelength range, such as in the wavelength range of 380 nm - 430 nm, more particularly 380 nm - 420 nm. In embodiments, the first luminescent material can comprise a Ce 3+ based luminescent material. Such material can absorb more at the longer wavelength range of the first light source light emission band than at the shorter wavelength range, which can also be advantageous.

[0133] In embodiments, the first luminescent material can comprise one or more of:

[0134] - garnets, such as (Lu 1-x-y-a-b Y x Gd y )3(Al 1-z-u Ga z Si u)5O 12-u N u :Ce a Pr b where 0≤x≤1, 0≤y≤1, 0 12 :Ce 3+ and Y3Al5O 12 :Ce 3+

[0135] - narrow green phosphors such as Ca8Mg(SiO4)4Cl2:Eu

[0136] - silicon oxynitrides such as (Sr 1-a-b-c Ca b Ba c )Si x N y O z :Eu a 2+ where a = 0.002-0.2, b = 0.0-0.25, c = 0.0-1.0, x = 1.5-2.5, y = 0.67-2.5, z = 1.5-4, including for example SrSi2N2O2:Eu 2+ and BaSi2N 0.67 O4:Eu 2+

[0137] - LSN such as (La,Y)Si6N 11 :Ce 3+

[0138] - Gallates such as (Sr 1-u-v-x Mg u Ca v Ba x )(Ga 2-y-z Al y In z S4):Eu 2+ where 0≤u+v+x≤1 and 0≤u+z≤2, including for example SrGa2S4:Eu 2+

[0139] - Silicates such as (Sr 1-x Ba x )2SiO4:Eu where 0 2+

[0140] (Ca 1-x-y-a-b Y x Lu y )3(Sc1-z Al z )2(Si 1-x-y Al x+y )3O 12 :Ce a Pr b wherein 0≤x≤1, 0≤y≤1, 0<z≤1, 0≤u≤0.2, 0<a≤0.2 and 0≤b≤0.1, such as Ca3Sc2Si3O 12 :Ce 3+

[0141] Ba3Si6O 15-3x N 2x wherein 0≤x≤5, including for example Ba3Si6O 12 N2:Eu 2+

[0142] β-SiAlON, such as Si (6-z) Al z O z N (8-z) :Eu 2+ wherein 0≤z≤6.

[0143] In embodiments, the first luminescent material comprises a (trivalent) cerium containing garnet luminescent material (such as comprising gallium and / or lutetium). Alternatively or additionally, the first luminescent material can comprise a (divalent) europium containing luminescent material.

[0144] However, other luminescent materials are not excluded herein.

[0145] As indicated above, the system can be configured to generate system light. The system light can comprise one or more of the first device light and the second device light. In particular, in an operational mode, the system light comprises both the first device light and the second device light. In embodiments, the system light can have a correlated color temperature selected from the range of 1800K-6500K. Further, in embodiments, the system light can have a (system light) color point within 0 SDCM-10 SDCM from the black body locus, and can have a color rendering index of at least 70 (such as at least 80). In particular embodiments, the system light can have a CRI of at least 85.

[0146] In embodiments, the system light comprising the first device light and the second device light has a correlated color temperature of at least 100K, such as at least 200K, like at least 500K, such as in embodiments at least 1000K higher than the correlated color temperature of the second device light. In particular embodiments, the difference in correlated color temperature between the second device light and the system light comprising the first device light and the second device light can be selected from the range of 500K-15000K, such as from the range of 500K-10000K.

[0147] In particular embodiments, the difference between the second device light and the first device light comprised by the system light in u' can be at least 0.02, even more particularly at least 0.04. In particular embodiments, the difference between the second device light and the first device light comprised by the system light in u' can be selected from the range of 0.06 - 0.14.

[0148] In particular embodiments, the difference between the second device light and the first device light comprised by the system light in v' can be at least 0.01, even more particularly at least 0.015. In particular embodiments, the difference between the second device light and the first device light comprised by the system light in v' can be selected from the range of 0.01 - 0.15.

[0149] Due to the presence of two types of light generating devices, the system light can be controlled. This can result in different types of system light, which can differ in one or more of the aspects of color point, correlated color temperature and CRI.

[0150] Hence, in particular embodiments, the light generating system can further comprise a control system. In particular, the control system can be configured to control the system light in dependence on one or more of an input signal of a user interface, a sensor signal (of a sensor) and a timer.

[0151] The term "control" and similar terms at least particularly refer to determining the behavior of an element or supervising the operation of an element. Hence, "control" and similar terms herein can for example refer to exerting behavior on an element (determining the behavior of an element or supervising the operation of an element), such as for example measuring, displaying, actuating, switching on, displacing, changing temperature, etc. In addition thereto, the term "control" and similar terms can additionally comprise monitoring. Hence, the term "control" and similar terms can comprise exerting behavior on an element and also comprise exerting behavior on an element and monitoring the element. The control of an element can be done with a control system, which can also be indicated as "controller". The control system and the element can thus be at least temporarily or permanently functionally coupled. The element can comprise the control system. In embodiments, the control system and the element can not be physically coupled. The control can be done via wired and / or wireless control. The term "control system" can also refer to a plurality of different control systems, which are in particular functionally coupled, and wherein for example one control system can be a master control system and one or more other control systems can be slave control systems. The control system can comprise or can be functionally coupled to a user interface.

[0152] The control system can also be configured to receive and execute instructions from a remote control. In embodiments, the control system can be controlled via an App on a device, such as a portable device, like a smart phone or I-phone, tablet, etc. Hence, the device does not necessarily have to be coupled to the lighting system, but can be (temporarily) functionally coupled to the lighting system.

[0153] Hence, in embodiments, the control system can (also) be configured to be controlled by an App on a remote device. In such embodiments, the control system of the lighting system can be a slave control system or be in slave mode. For example, the lighting system can be identified with a code, in particular a unique code for the respective lighting system. The control system of the lighting system can be configured to be controlled by an external control system that has access to the lighting system based on knowledge of the (unique) code (by input via a user interface with an optical sensor, e.g. a QR code reader). The lighting system can also comprise means for communication with other systems or devices, such as based on Bluetooth, WIFI, LiFi, ZigBee, BLE or WiMAX or another wireless technology.

[0154] A system, apparatus or device can perform an action in a “mode” or “operating mode” or “mode of operation” or “operable mode”. The term “operable mode” can also be indicated as “control mode”. Similarly, in a method, an action or phase or step can be performed in a “mode” or “operating mode” or “mode of operation” or “operable mode”. This does not exclude that the system or apparatus or device can also be adapted to provide another control mode, or a plurality of other control modes. Similarly, this can not exclude that one or more other modes can be performed before and / or after performing this mode.

[0155] However, in embodiments, a control system can be available that is adapted to provide at least a control mode. If other modes are available, the selection of such a mode can in particular be performed via a user interface, but other options, like performing a mode according to a sensor signal or a (time) scheme, are also possible. In embodiments, the operating mode can also refer to a system, apparatus or device that can only operate in a single operating mode, i.e. “on”, without further tunability.

[0156] Hence, in embodiments, the control system can be controlled according to one or more of an input signal of a user interface, a sensor signal (of a sensor) and a timer. The term “timer” can refer to a clock and / or a predetermined time scheme.

[0157] In particular, in embodiments, the control system can be configured to individually control the first light generating devices and the second light generating devices. This can for example allow for a first device light mode or a first device light rich mode only, and a second device light mode or a second device light rich mode only.

[0158] In particular embodiments, the light generating system can further comprise a support, e.g. a PCB, but other supports are possible as well. Further, the light generating system can comprise n1 multiple first light generating devices and n2 multiple second light generating devices (both) configured to be supported by the support. The support can comprise a printed circuit board, but other options are possible as well.

[0159] In embodiments, n2 < n1. In other embodiments, n2 = n1. Further, in other embodiments, n2 > n1. In particular, in embodiments, one or more of the following can apply: (i) n1 > 2 and (ii) n2 > 2. In particular embodiments, the first light generating devices can be configured as one or more rows.

[0160] In particular embodiments, the n1 multiple first light generating devices and the n2 multiple second light generating devices can comprise a subset comprising at least two first light generating devices and more than two second light generating devices, wherein in particular all second light generating devices in the subset have an equal second pitch p2. In this way, switching on or off or increasing or decreasing the intensity of the first light generating devices can have little or no impact on the uniform spatial distribution of the second device light.

[0161] In particular embodiments, 0.05 < n1 / n2 < 0.75. However, in other embodiments, n1 / n2 > 0.75. However, other values of n1 / n2 < 0.05 are possible as well.

[0162] In embodiments, the system can have an operating mode in which a substantially continuous white system is provided, including a (small) disinfection component provided by the first device light. In such embodiments, for example n2 > n1.

[0163] In embodiments, the system can have a boost function, e.g. for disinfection at night or after use of the room, etc. In such embodiments, n2 = n1 or even n2 < n1.

[0164] In embodiments, n2 = n1, with for example a splitter, which allows for variable relative intensity of the first device light and the second device light, optionally including only one of the first device light and the second device light.

[0165] Optionally, downstream of the first light generating device and / or the second light generating device, optical devices, such as beam shaping optical devices, can be configured. The term “optical device” can in particular refer to optical element(s). Hence, the terms “optical device” and “optical element” can refer to the same item. The optical device can comprise one or more mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, gratings, dichroic mirrors, arrays of one or more of the foregoing, etc. Alternatively or additionally, the term “optical device” can refer to a holographic element or a hybrid rod. In embodiments, the optical device can comprise one or more of expander optics and zoom lens optics. In embodiments, the optical device can comprise light mixing optics. In embodiments, the light mixing optics can comprise one or more of a diffuser (surface or volume scattering diffuser or engineered holographic optical element), a light pipe, a light guide, Koehler integrator optics, etc. Alternatively or additionally, the light mixing optics can comprise a collimator or other collimating optics.

[0166] The terms “upstream” and “downstream” relate to the arrangement of items or features with respect to the propagation of light from a light generating component (here in particular a light source), wherein a second position in the light beam closer to the light generating component is “upstream” and a third position in the light beam further away from the light generating component is “downstream” with respect to a first position in the light beam from the light generating component.

[0167] The light generating system can be, for example, part of or can be applied in an office lighting system, a home application system, a shop lighting system, a home lighting system, a spot lighting system, a spotlight system, a theater lighting system, a fiber application system, a projection system, a self-luminous display system, a pixelated display system, a segmented display system, a warning sign system, a medical lighting application system, an indication sign system, a decorative lighting system, a portable system, a motor vehicle application, an (outdoor) road lighting system, a city lighting system, a greenhouse lighting system, horticulture lighting, digital projection or LCD backlighting, or can be applied in. The light generating system (or luminaire) can be, for example, part of or can be applied in a light communication system or a disinfection system.

[0168] In yet another aspect, the present application also provides a lamp or luminaire comprising a light generating system as defined herein. The luminaire can further comprise a housing, optical elements, louvers, etc. The lamp or luminaire can further comprise a housing enclosing the light generating system. The lamp or luminaire can comprise a light window in the housing or a housing opening through which system light can escape from the housing. In yet another aspect, the present application also provides a projection apparatus comprising a light generating system as defined herein. In particular, a projection apparatus or "projector" or "image projector" can be an optical device that projects (or moves) an image onto a surface (e.g. such as a projection screen). The projection apparatus can comprise one or more light generating systems such as described herein. Hence, in an aspect, the present application also provides a lighting apparatus selected from the group of a lamp, a luminaire, a projector apparatus, a disinfection apparatus, a photochemical reactor and an optical wireless communication apparatus, comprising a light generating system as defined herein. The lighting apparatus can comprise a housing or carrier configured to house or support one or more elements of the light generating system. For example, in embodiments, the lighting apparatus can comprise a housing or carrier configured to house or support one or more of a first light generating device, a second light generating device, a support, etc. Hence, the present application also provides a lighting apparatus selected from the group of a lamp, a luminaire, a disinfection apparatus and an optical wireless communication apparatus, comprising a light generating system as defined herein.

[0169] In one aspect, the present invention also provides a light generating system configured to generate system light, wherein: the first light generating device comprises a first light source and a first luminescent converter; and the first light source comprises a solid state light source, wherein the first light source is configured to generate first light source light having a first light source peak wavelength selected from the range of (about) 380-430 nm, more particularly 380-420 nm. In one aspect, the present invention also provides a light generating system configured to generate system light, wherein: the first light generating device comprises a first light source and a first luminescent converter; and the first luminescent converter is configured to convert at least part of the first light source light into first converter light having a color point in the green-yellow wavelength range. In particular, in one aspect, the present invention also provides a light generating system configured to generate system light, wherein the light generating system comprises a first light generating device, wherein: (A) the first light generating device comprises a first light source and a first luminescent converter; (B) the first light source comprises a solid state light source, wherein the first light source is configured to generate first light source light having a first light source peak wavelength selected from the range of (about) 380-430 nm, more particularly 380-420 nm; (C) the first luminescent converter is configured to convert at least part of the first light source light into first converter light having a color point in the green-yellow wavelength range; (D) the first light generating device is configured to generate first device light having a spectral power distribution in the wavelength range of 380-780 nm, wherein at least 60% of the spectral power is provided by the first light source light and at most 40% of the spectral power is provided by the first converter light.

[0170] In yet another further aspect, the present invention provides such a first light generating device in combination with a second light generating device, wherein: (A) the second light generating device comprises a second light source and a second luminescent converter; (B) the second light source comprises a solid state light source, wherein the second light source is configured to generate second light source light having a second light source peak wavelength selected from the range of (about) 440-490 nm; (C) the second luminescent converter is configured to convert at least part of the second light source light into second converter light having a color point in the green-red wavelength range; (D) the second light generating device is configured to generate second device light having a spectral power distribution in the wavelength range of 380-780 nm, wherein at least 60% of the spectral power is provided by the second converter light and at most 40% of the spectral power is provided by the second light source light, wherein the second device light is white light; (E) the first device light spectral power distribution of the first device light and the second device light spectral power distribution of the second device light can be different.

[0171] In yet another further aspect, the application provides a method for processing at least part of a space or an object (external to a light generating system or a light generating device), wherein the method can particularly comprise: using a light generating system as defined herein or a lighting device as defined herein to provide system radiation comprising first device light in the space or to the object. BRIEF DESCRIPTION OF DRAWINGS

[0172] Embodiments of the application will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference signs indicate corresponding parts, and in which:

[0173] Figures la-le Some aspects and embodiments are schematically depicted;

[0174] Figure 2 Some emission and excitation spectra are shown;

[0175] Figure 3 A u’v’ plot is shown with some light generating device (light) color points;

[0176] Figures 4a-b Some LED spectra are shown that are dependent on the presence of a (first) luminescent material;

[0177] Figure 5 Embodiments of system light are shown; and

[0178] Figure 6 Some application embodiments are schematically depicted.

[0179] The schematic drawings are not necessarily to scale. DETAILED DESCRIPTION

[0180] Figures la-b Some embodiments and aspects are schematically depicted. Figure la Embodiments I and II of Figure lb Embodiment II of the application schematically depicts an embodiment of a light generating system 1000 configured to generate system light 1001. The light generating system 1000 particularly comprises a first light generating device 110. The first light generating device 110 can comprise a first light source 10 and a first luminescent converter 210. In particular, the first light source 10 can comprise a solid state light source. The first light source 10 can be configured to generate first light source light 11 having a first light source centroid wavelength λ s,1 , the first light source centroid wavelength λ s,1For example selected from the range of 380 nm - 430 nm, such as 380 nm - 425 nm, more particularly 380 nm - 420 nm. The first luminescence converter 210 can be configured to convert (at least) part of the first light source light 11 into first converter light 211 having a first converter centroid wavelength λ c,1 Further, the first light generating device 110 can be configured to generate first device light 111 having a spectral power distribution within the wavelength range of 380 nm - 780 nm, for example, wherein at least 60% of the spectral power is provided by the first light source light 11 and at most 40% of the spectral power is provided by the first converter light 211.

[0181] In embodiments, the first light source centroid wavelength λ s,1 may be selected from the range of 395 nm - 415 nm.

[0182] In embodiments, the first luminescence converter 210 can comprise a first host material 215 and a first luminescent material 216, wherein the first luminescent material 216 has a first weight percentage CW1 relative to the total weight of the first luminescence converter 210. In embodiments, CW1 < 10 wt.%.

[0183] In particular, the first luminescence converter 210 can be configured to convert the first light source light 11 into first converter light 211 having a first converter centroid wavelength λ c,1 However, other options are possible as well.

[0184] In embodiments, the first device light 111 can have a correlated color temperature selected from the range of 6000 K - 25000 K. Further, the first device light 111 can have a (first device light) color point selected within 0 SDCM - 20 SDCM from the black body locus. Further, the first device light 111 can have a color rendering index of at most 70. In embodiments, the first light source centroid wavelength λ s,1 is selected from the range of 400 nm - 410 nm.

[0185] In order to obtain an energy efficient and cost efficient solution, both the first light generating device and the second light generating device (like a white LED package) need to be highly efficient. A device comprising a blue LED + white LED light source can result in an overall efficiency that is about 22% lower than a device based on a standard white LED. This can be undesirable.

[0186] The possibility of some devices to couple out from the transparent silicone layer on top of the chip is relatively low, for example, because the surface is typically concave, at most close to flat. One example of the first light generating device 110 is in Figure lbThe left side of embodiment I in Fig. 1 is schematically depicted, but without the first luminescent material, but with a resin (here indicated with reference 215). The emission spectrum thereof is shown on the right side of embodiment I. Basically, the first device light of such a device without the first luminescent material can consist of the first light source light 11.

[0187] The addition of the violet light generating device can also shift the color point towards the blue (lower v'). In combination with the standard white light generating device, this can limit the amount of violet light that can be added. Too high contribution of violet can shift the color point out of the ANSI-bin.

[0188] In particular, the present invention proposes to add a minimal volume of phosphor particles in a short wavelength (in particular around 405 nm) LED package to provide a first light generating device to facilitate light extraction and thus improve the efficiency and to cause some phosphor conversion to reach the desired color point. In particular, the combination of violet pump light and phosphor converted light can have a color point close to the BBL, which allows to add a higher amount of violet light in combination with a standard white light generating device (such as a LED).

[0189] Using a violet light generating device (without scatterer or phosphor) can result in a reduced package efficiency, as some of the light is trapped in the transparent silicone (protective) layer on top of the chip. A part of the light emitted by the chip will experience total internal reflection at the air-silicone interface and will eventually be absorbed by the package interior (e.g. by the die). Adding phosphor particles in the transparent silicone can increase the light extraction due to more scattering in the transparent silicone layer, resulting in a larger extraction probability.

[0190] Figure lb The principle is schematically shown. A slightly changed spectrum is beneficial for this application (color point of the white emission). In combination with a standard white light generating device, a white (within ANSI) color point can be created. In a pure disinfection mode (only the 405 nm LED is on), the emission will be a cool white with low color rendering. This mode can for example only be used when the room is empty, so the low color rendering property is acceptable (applying this concept to a standard blue, green or red light generating device is not acceptable, as it affects the purity of the direct color).

[0191] Hence, especially in a 405 nm chip package, a little green / yellow phosphor can be provided to provide a first light generating device so that the color point of this package (i.e. the resulting first device light) moves towards the BBL. At the same time, the extraction efficiency can thereby be increased.

[0192] Reference Figures lc-leIn a particular embodiment, the light generating system 1000 can further comprise a second light generating device 120. The second light generating device 120 can comprise a second light source 20 and a second luminescent converter 220. The second light source 20 can comprise a solid state light source. The second light source 20 can be configured to generate second light source light 21 (such as having a second light source centroid wavelength (l s,2 )) selected from the range of 440 nm - 490 nm. The second luminescent converter 220 can be configured to convert at least a part of the second light source light 21 into second converter light 221 (such as having a second converter centroid wavelength (l c,2 )) selected from the green-red wavelength range. The second light generating device 120 can be configured to generate second device light 121 having a spectral power distribution in the wavelength range of 380 nm - 780 nm, wherein at least 60% of the spectral power is provided by the second converter light 221 and at most 40% of the spectral power is provided by the second light source light 21. The second device light 121 can be white light. The first device spectral power distribution of the first device light 111 and the second device spectral power distribution of the second device light 121 can be different (see also below).

[0193] In an embodiment, the second light source centroid wavelength (l s,2 ) can be selected from the range of 445 nm - 480 nm. The second luminescent converter 220 can comprise a second host material 225 and a second luminescent material 226. The second luminescent material 226 can have a second weight percentage CW2 relative to the total weight of the second luminescent converter 210. In an embodiment, CW2 can be at least 20 weight %.

[0194] The second device light 121 can have a correlated color temperature selected from the range of 1800 K - 6500 K, a (second device light) color point within 0 SDCM - 15 SDCM from the black body locus, and a color rendering index of at least 70.

[0195] The first luminescent material 216 can comprise a particulate material. The first host material 215 can comprise a resin (in particular a silicone resin). The second luminescent material 226 can comprise a particulate material. The second host material 225 can comprise a resin (in particular a silicone resin). In an embodiment, the first luminescent material 216 can comprise one or more of a Eu 2+ -based luminescent material and a Ce 3+ -based luminescent material.

[0196] In embodiments, CW1 / CW2 < 0.3. In embodiments, the first luminescent material 216 can have a first volume percentage CV1 of the first luminescent material 216 in the first luminescent converter 210. Further, the second luminescent material 226 can have a second volume percentage V2 of the second luminescent material 226 in the second luminescent converter 220. In embodiments, CV1 / V2 < 0.3.

[0197] In embodiments, at least 50 wt.% of the first luminescent material 216 has a particle size selected from the range of 1 pm - 20 pm.

[0198] In embodiments, at most 20% of the spectral power, relative to the spectral power distribution of the first converter light 211 in the range of 380 nm - 780 nm, can be in the range of 585 nm - 780 nm.

[0199] In embodiments, at most 30% of the spectral power, relative to the spectral power distribution of the second device light 121 in the range of 380 nm - 780 nm, can be provided by the second light source light 21.

[0200] In particular embodiments, the system light 1001 can have a correlated color temperature selected from the range of 1800 K - 6500 K, a (system light) color point within 0 SDCM - 10 SDCM from the black body locus, and a color rendering index of at least 70.

[0201] In embodiments, the light generating system 1000 can further comprise a control system 300. In particular, the control system 300 can be configured to control the system light 1001 as a function of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. In embodiments, the control system 300 can be configured to individually control the first light generating device 110 and the second light generating device 120.

[0202] Reference is made to Figure le , the light generating system 1000 can further comprise a support 600. The light generating system 1000 can comprise n1 multiple first light generating devices 110 and n2 multiple second light generating devices 120 (both) configured to be supported by the support 600. In embodiments, the first light generating devices 110 are configured as one or more rows. In embodiments, the n1 multiple first light generating devices 110 and the n2 multiple second light generating devices 120 can comprise a subset 1050 comprising at least two first light generating devices 110 and two more second light generating devices 120. In particular embodiments, all second light generating devices 120 in the subset 1050 have an equal second pitch p2. Reference P1 refers to a pitch of the first light generating devices 110.

[0203] In embodiments, the range of options includes adding the LEDs to the same row (I, II) or adding them next to the white LED row (III). Furthermore, in options I and III, the resulting white LED positioning can remain the same as the original white LED L2. As a result, the white light uniformity can be substantially unchanged; there can be no speckling from the violet color as in option II. With option II, a proper luminaire optical design can still yield an acceptable luminaire solution.

[0204] Figure 2 A short wavelength blue emission peak at an approximate 405 nm peak wavelength / first light source centroid wavelength λ s,1 of the first light source 11 is shown, as well as the excitation spectrum of the different luminescent materials, indicated with the starting letter X, and the emission spectrum, indicated with the starting letter M. The luminescent materials are indicated with the second letters a, b, c, and d, and are: a divalent europium-based narrow green phosphor (a), a divalent europium-based silicate (b), a YAG-type luminescent material containing gallium (c), and a YAG-type material containing lutetium (d).

[0205] The excitation spectrum of the divalent europium-based narrow green phosphor (a) and the divalent europium-based silicate (b), Xa and Xb, respectively, have a good overlap with the first light source light 11; the excitation spectrum of the YAG-type luminescent material containing gallium (c) and the YAG-type luminescent material containing lutetium (d), Xc and Xd, respectively, have a higher overlap on the long wavelength side than on the short wavelength side of the first light source light 11.

[0206] As an example, the centroid wavelength λ c,1 of the emission ma of the divalent europium-based narrow green phosphor (a) and the emission mb of the divalent europium-based silicate (b) are indicated schematically. Note that the centroid wavelengths indicated schematically herein can not necessarily match the calculated centroid wavelengths exactly, as these centroid wavelengths are indicated herein only for reference purposes. Furthermore, note that the centroid wavelengths do not necessarily coincide with the peak wavelength or maximum of the emission band.

[0207] Figure 3 A u’v’ color point plot of different light generating devices is depicted. As an example, different standard white LEDs (2700 K, 3000 K, 4000 K, and 6500 K) are combined with a violet LED. The white LEDs can for example have a high CRI, such as in embodiments CRI > 90. The violet LED can for example contain some divalent europium-based phosphor, here in particular, in embodiments, BaSrSi04:Eu 2+ The larger the amount of luminescent material, the higher the v’ value.

[0208] Note that the color point of the first device light can thus be on a line connecting the color point of the second device light and the color point of the desired application color point (and thus, all three color points can be on the same line). When the CCT of the second device light is relatively low, the color point of the first device light can be relatively far away from the BBL. When the CCT of the second device light is relatively high, the color point of the first device light can be relatively close to the BBL. This is schematically shown using a second device light of 6500 K as an example. The dotted line b from a color point on or close to the BBL to a system light color point that is also on or close to the BBL will follow this dotted line. The intersection with line a provides the color point of the first device light, line a showing the color point of the first device light as a function of the relative amount (or volume) of the first luminescent material (in a host). Line c indicates a part of the boundary of the color triangle.

[0209] The light of the standard white LED is mixed with light from the violet light pumped divalent europium-based phosphor LED in different proportions to generate color points of higher CCT. Depending on the color point of the divalent europium-based phosphor / 405 nm LED, the color point can be below the BBL (the divalent europium-based phosphor thickness is too low), along the BBL or above the BBL (the divalent europium-based phosphor thickness is too high).

[0210] For a 2700 K white LED, the required phosphor thickness to generate a color point along the BBL can be determined. The CCT of the violet LED is about 13000 K, with a CRI of about 39 and an R9 of -218. At the (combined color) point with the highest CCT (about 3500 K), about 19% of the lumen flux is generated by the violet / BaSrSi04:Eu 2+ LED; the CRI of the combined white spectrum is still 91. The white spectrum can contain 1.7 mW of violet light / Lm.

[0211] For a 4000 K white LED, the required phosphor thickness to generate a color point along the BBL can be determined. The CCT of the violet LED is about 21600 K, with a CRI of about 39 and an R9 of -198. At the (combined color) point with the highest CCT (about 5000 K), about 16% of the lumen flux is generated by the violet / divalent europium-based phosphor LED; the CRI of the combined white spectrum is still 89. The white spectrum can contain 1.9 mW of violet light / Lm.

[0212] As can be derived from Figure 3 In a particular embodiment, the first device light 111 can have a color point with a u’ selected from the range of 0.10 - 0.22 and a v’ selected from the range of 0.30 - 0.55.

[0213] Cerium-based green phosphors, such as in particular LuAG:Ce, can have a desirable excitation spectrum, see Figure 4a. Figure 4a The spectrum of the violet-based light generating device (first device light 111) as a function of the amount of first luminescent material is shown in embodiment I, and the (remaining) emission of the first light source light 11 as a function of the amount of first luminescent material is shown in embodiment II. In Figure 4b embodiment III, this is shown for a divalent europium-based luminescent material. LuAG:Ce Figure 4a ) mainly absorbs the long wavelength part of the first light source light, which is expected to be slightly less effective in inactivating pathogens. Hence, the more effective part of the spectrum is still present.

[0214] The conversion loss of the 405 nm light can be compensated by increasing the relative amount of the violet-based light generating device, and the efficiency loss due to the larger Stokes shift of the phosphor converted light is very limited (about 1%). The PE increase due to better coupling out exceeds expectations to compensate for this effect.

[0215] Figure 5 Embodiments of the system light 1001 based on a synthesis of the first device light 111 and the second device light 121 are schematically depicted. With reference to the second device light 121, the spectral power distribution (over the wavelength range of 380 nm - 780 nm) of the second device light 121 can comprise a spectral power provided by the second light source light 21 in the range of 10% - 30% and a spectral power provided by the second converter light in the range of 70% - 90%.

[0216] Figure 6 Embodiments of the luminaire 2 comprising the light generating system 1000 as described above are schematically depicted. Reference 301 indicates a user interface, which can be functionally coupled to a control system 300, which is comprised by the light generating system 1000 or which is functionally coupled to the light generating system 1000. Figure 6 Embodiments of the lamp 1 comprising the light generating system 1000 are also schematically depicted. Reference 3 indicates a projector device or projector system, which can be used for projecting an image (such as on a wall), which can also comprise the light generating system 1000. Hence, Figure 6 Embodiments of a lighting device 1200 selected from the group of lamp 1, luminaire 2, projector device 3, disinfection device, photochemical reactor and optical wireless communication device, comprising the light generating system 1000 as described herein are schematically depicted. In embodiments, such lighting device can be a lamp 1, luminaire 2, projector device 3, disinfection device or optical wireless communication device. The lighting device light escaping from the lighting device 1200 is indicated with reference 1201. The lighting device light 1201 can essentially consist of the system light 1001, and hence can in particular embodiments be the system light 1001.

[0217] In particular, with the present application, a method for processing at least part of a space 1300 or an object (external to the light generating system 1000 or the light generating device 1200) can be provided. The method can comprise providing system radiation 1001 comprising first device light 111 in the space 1300 or to the object using a light generating system 1000 as described herein or a lighting device 1200 as described herein.

[0218] The term "plurality" refers to two or more.

[0219] The term "substantially" or "approximately" and similar terms in the present text are understood by a person skilled in the art. The term "substantially" or "approximately" can also include embodiments with "all", "completely", "all of", etc. Thus, in embodiments, the adjective substantially or approximately can also be removed. Where applicable, the term "substantially" or the term "approximately" can also relate to 90% or more, such as 95% or more, in particular 99% or more, even more particularly 99.5% or more, including 100%.

[0220] The term "comprising" also includes embodiments where the term "comprising" means "consisting of".

[0221] The term "and / or" particularly relates to one or more of the items it connects. For example, the phrase "item 1 and / or item 2" and similar phrases can relate to one or more of item 1 and item 2. The term "comprising" can in one embodiment mean "consisting of", but can in another embodiment also mean "including at least the defined material and optionally one or more other materials".

[0222] Further, 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 application described herein are capable of operation in other sequences than described or illustrated herein.

[0223] A device, apparatus or system can herein particularly be described during operation. It will be understood by those skilled in the art that the application is not limited to the method of operation, or to apparatuses or systems in operation, described herein.

[0224] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that one skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

[0225] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0226] The use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in the claims. Throughout the description and claims, the word "comprise" and its conjugations shall not be interpreted as an exhaustive recitation of the meaning of the term "comprise" or its conjugations. Rather, the word "comprise" and its conjugations shall be interpreted in a manner that is inclusive of the meaning of the term "comprise" and its conjugations.

[0227] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0228] The application can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim, or apparatus claim, or system claim, several elements can be listed that might be implemented by means of 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 another aspect, the application (thus) provides a software product, which when run on a computer, is capable of implementing the method(s) described herein.

[0229] The application also provides a control system, which can control a device, apparatus or system, or which can execute a method or process described herein. Yet further, the application also provides a computer program product, which when run on a computer functionally coupled to or comprised by a device, apparatus or system, controls one or more controllable elements of such device, apparatus or system.

[0230] The application also applies to a device, apparatus or system comprising one or more of the characterising features described in the description and / or shown in the attached drawings. The application also relates to a method or process comprising one or more of the characterising features described in the description and / or shown in the attached drawings.

[0231] The various aspects discussed in this patent can be combined to provide additional advantages. Furthermore, those skilled in the art will appreciate that embodiments can be combined, and more than two embodiments can also be combined. Moreover, some of the features can form the basis of one or more divisional applications.

Claims

1. A light generating system (1000) configured to generate system light (1001), wherein the light generating system (1000) comprises a first light generating device (110); wherein: the first light generating device (110) comprises a first light source (10) and a first luminescent converter (210); The first light source (10) comprises a solid state light source, wherein the first light source (10) is configured to generate first light source light (11) having a first light source centroid wavelength (λ s,1 ) selected from the range of 380 nm to 420 nm; The first luminescence converter (210) is configured to convert a portion of the first light source light (11) into first converter light (211) having a first converter centroid wavelength (λ c,1 ) selected from a green-yellow wavelength range; the first light generating device (110) is configured to generate first device light (111) having a spectral power distribution in the wavelength range of 380-780 nm of which at least 60% of the spectral power is provided by the first light source light (11) and at most 40% of the spectral power is provided by the first converter light (211); wherein the first luminescent converter (210) comprises a first host material (215) and a first luminescent material (216), wherein the first luminescent material (216) has a first weight percentage CW1 relative to the total weight of the first luminescent converter (210); wherein the light generating system further comprises a second light generating device (120), wherein the second light generating device (120) comprises a second light source (20) and a second luminescent converter (220); wherein the second light source (20) comprises a solid state light source, wherein the second light source (20) is configured to generate second light source light (21); wherein the second luminescent converter (220) is configured to convert at least part of the second light source light (21) into second converter light (221); and wherein the second light generating device (120) is configured to generate second device light (121) having a spectral power distribution in the wavelength range of 380-780 nm of which at least 60% of the spectral power is provided by the second converter light (221) and at most 40% of the spectral power is provided by the second light source light (21); wherein the second luminescent converter (220) comprises a second host material (225) and a second luminescent material (226), wherein the second luminescent material (226) has a second weight percentage CW2 relative to the total weight of the second luminescent converter (220); and wherein CW1 / CW2 < 0.

5.

2. The light generating system (1000) according to claim 1, wherein the first light source centroid wavelength (λ s,1 ) is selected from a range of 395 nm to 415 nm, wherein the first luminescence converter (210) is configured to convert the first light source light (11) into first converter light (211) having the first converter centroid wavelength (λ c,1 ) selected from a green wavelength range.

3. The light generating system (1000) according to claim 1 or 2, wherein CW1 < 10 wt.%; wherein the first light source centroid wavelength (l s,1 ) is selected from the range of 400 nm to 410 nm; and wherein the color point of the first device light (111) has u’ selected from the range of 0.10 to 0.22 and has v’ selected from the range of 0.30 to 0.

55.

4. The light generating system (1000) according to claim 1 or 2, wherein the second device light (121) is white light.

5. The light generation system (1000) according to claim 4, wherein the second light source light (21) has a second light source centroid wavelength (λ) selected from the range of 445 nm to 480 nm. s,2 The second device light (121) has a correlated color temperature selected from the range of 1800K to 6500K, a color point within 0 SDCM to 15 SDCM from the blackbody locus, and a color rendering index of at least 70.

6. The light generating system (1000) according to claim 1 or 2, wherein CW1 / CW2 < 0.3; wherein the first luminescent material (216) comprises a particulate material, and wherein the first host material (215) comprises a resin; wherein the second luminescent material (226) comprises a particulate material, and wherein the second host material (225) comprises a resin.

7. The light generating system (1000) according to claim 1 or 2, wherein CW2 is at least 20 wt.%.

8. The light generating system (1000) according to claim 1 or 2, wherein: at least 50 percent by weight of the first luminescent material (216) has a particle size selected from the range of 1 pm to 20 pm; at most 20 percent of the spectral power of the first converter light (211) is in the range of 585 nm to 780 nm relative to the spectral power distribution of the first converter light (211) in the range of 380 nm to 780 nm; and at most 30 percent of the spectral power of the second device light (121) is provided by the second light source light (21) relative to the spectral power distribution of the second device light (121) in the range of 380 nm to 780 nm.

9. The light generating system (1000) according to claim 1 or 2, wherein the first luminescent material (216) comprises one or more of: a luminescent material based on Eu 2+ , and a luminescent material based on Ce 3+ .

10. The light generating system (1000) according to claim 1 or 2, wherein the system light (1001) has a correlated color temperature selected from the range of 1800 K to 6500 K, a color point within 0 SDCM to 10 SDCM from the black body locus, and a color rendering index of at least 70.

11. The light generating system (1000) according to claim 1 or 2, further comprising a control system (300), wherein the control system (300) is configured to control the system light (1001) in dependence on one or more of: an input signal of a user interface, a sensor signal, and a timer.

12. The light generating system (1000) according to claim 11, wherein the control system (300) is configured to: control the first light generating device (110) and the second light generating device (120) individually.

13. The light generating system (1000) according to claim 1 or 2, further comprising a support (600), wherein: the light generating system (1000) comprises a plurality of n1 first light generating devices (110) and a plurality of n2 second light generating devices (120) configured to be supported by the support (600); the plurality of n1 first light generating devices (110) and the plurality of n2 second light generating devices (120) comprise a subset (1050) comprising at least two first light generating devices (110) and more than two second light generating devices (120), wherein all second light generating devices (120) in the subset (1050) have an equal second pitch (p2).

14. A lighting device (1200) selected from the group of a lamp (1), a luminaire (2), a disinfection device, and an optical wireless communication device, the lighting device (1200) comprising the light generating system (1000) according to claim 1.

15. A method for processing a space (1300) or at least a portion of an object, wherein the method comprises: using the light generating system (1000) according to claim 1 or the lighting device (1200) according to claim 14 to provide a system light (1001) comprising the first device light (111) in the space (1300) or to the object. using the light generating system (1000) according to claim 1 or the lighting device (1200) according to claim 14 to provide a system light (1001) comprising the first device light (111) in the space (1300) or to the object.

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