A light emitting device

Abstract

A light emitting device (1) configured to provide, in operation, device light (2) and comprising a first solid-state light source (3) configured to provide, in operation, first light source light (4) having a first peak emission wavelength, λ1, in a wavelength range from 420 to 490 nm and having a first full-width-half-max, FWHM1, of at least 60 nm, and a second peak emission wavelength, λ2, in a wavelength range from 600 to 660 nm and having a second full-width-half-maximum, FWHM2, of at least 60 nm, a second solid-state light source (5) configured to provide, in operation, second light source light (6) having a third peak emission wavelength, λ3, in a wavelength range from 515 to 535 nm and having a third full-width-half-maximum, FWHM3, of at most 35 nm, and a controller (30) configured to individually control the first solid-state light source (3) and the second solid-state light source (5), wherein, in a first operational mode of the light emitting device (1), the device light (2) comprises the first light source light (4) and the second light source light (6), and wherein the device light (2) is white light having a correlated color temperature, CCT, in a range from 2500 K to 6500 K and having a luminous flux in a range from 20 to 200 lm.

Description

[0001] 2024PF80497

[0002] 1

[0003] A light emitting device

[0004] FIELD OF THE INVENTION

[0005] The invention relates to a light emitting device configured to provide, in operation, device light, and comprising a LED light source configured to provide, in operation, light source light having a peak emission wavelength, 2, in the green wavelength range.

[0006] BACKGROUND OF THE INVENTION

[0007] Lighting systems utilizing solid-state light sources, such as LEDs, are widely used for various applications, including general illumination and specialized lighting. Recent advancements have explored the therapeutic potential of light, particularly green light, in treating migraine or other neurological disorders such as fibromyalgia, neuropathy, or chronic headaches.

[0008] US 9,500,327 B2 discloses a light-emitting arrangement, which is adapted to produce white output light enhancing the color perception of, e.g., food in retail environments. The light-emitting arrangement comprises at least one blue light-emitting element adapted to emit light having an emission peak in a first wavelength range of from 440 to 460 nm, and at least one deep blue light-emitting element adapted to emit light having an emission peak in a second wavelength range of from 400 to 440 nm. Further, the lightemitting arrangement comprises at least one narrow band wavelength converting material arranged to receive light emitted by said deep blue light-emitting element, and at least one broadband wavelength converting material arranged to receive light emitted by at least one of said blue light-emitting element and said deep blue light-emitting element.

[0009] However, there is still a desire to provide a light emitting device configured for treating migraine or other neurological disorders which light emitting device provides light with a low lux level (dim) white light for migraine reduction consisting of high-intense optimum-wavelength narrow-band green light and mild broad-band blue and red light.

[0010] SUMMARY OF THE INVENTION2024PF80497

[0011] 2

[0012] It is an object of the present invention to overcome this problem, and to provide a light emitting device configured for treating migraine or other neurological disorders which light emitting device is capable of providing device light comprising a low lux level (dim) white light for migraine reduction consisting of high-intense optimumwavelength narrow-band green light and mild broad-band blue and red light.

[0013] As used herein, the term “blue light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 420 nm to 490 nm.

[0014] As used herein, the term “green light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 500 nm to 550 nm.

[0015] As used herein, the term “red light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 600 to 780 nm.

[0016] As used herein, the term “solid state light source” is intended to refer to any solid state light source, including LEDs as well as diode lasers, super-luminescent diodes, and multi -junction diodes, comprising one or more LEDs.

[0017] According to a first aspect of the invention, this and other objects are achieved by means of a light emitting device configured to provide, in operation, device light, the light emitting device comprising a first solid-state light source configured to provide, in operation, first light source light having a first peak emission wavelength, I, in a wavelength range from 420 to 490 nm and having a first full-width-half-max, FWHM1, of at least 60 nm, and a second peak emission wavelength, X2, in a wavelength range from 600 to 660 nm and having a second full-width-half-maximum, FWHM2, of at least 60 nm, a second solid-state light source configured to provide, in operation, second light source light having a third peak emission wavelength, X3, in a wavelength range from 515 to 535 nm and having a third full-width-half-maximum, FWHM3, of at most 35 nm, and a controller configured to individually control the first solid-state light source and the second solid-state light source, wherein, in a first operational mode of the light emitting device, the device light comprises the first light source light and the second light source light, and wherein the device light is white light having a correlated color temperature, CCT, in a range from 2500 K to 6500 K and having a luminous flux in a range from 20 to 250 Im.

[0018] “White light” is used herein may be light having a color point within 20 SDCM, preferably within 15 SDCM, from the Planckian locus, a.k.a the black body locus BBL, e.g., in a CCT range 2500K to 6500K or in a CCT range from 2700K to 4500K. Herein, SDCM stands for Standard Deviation of Color Matching, a metric used in LED lighting to2024PF80497

[0019] 3

[0020] define color points, color consistency and precision between different light sources or color points, often referred to as MacAdam ellipses. Thereby, a light emitting device configured for treating migraine or other neurological disorders which light emitting device is capable of providing device light comprising a low lux level (dim) white light for migraine reduction consisting of high-intense optimum-wavelength narrow-band green light and mild broad-band blue and red light is provided for.

[0021] The spectrum or spectral power distribution of the first solid-state light source, i.e., the first light source light comprising the mild broad-band blue and red light, is substantially fixed and the controller is adapted to only control an intensity of the first light source light, therewith controlling a contribution of mild broad-band blue and red light to the device light, without controlling the spectrum or spectral power distribution of the first light source light. This provides a more simple light emitting device than known RGB light emitting devices used for generating white light that comprise individually controlled blue and red light sources. Moreover, the disclosed light emitting device provides a more consistent white light spectrum than such known RGB light emitting devices because the spectrum or spectral power distribution of the blue and red components in the white light is substantially constant.

[0022] The device light may be white light having a correlated color temperature, CCT, in a range from 2700K to 4500K.

[0023] The device light may be white light having a luminous flux in a range from 20-200 Im, or 20-180 Im, or 20-150 Im.

[0024] The controller may in a second operational mode of the light emitting device be configured to vary, particularly increase, the relative contribution of the second light source light to the total spectral power distribution of the device light in the visible wavelength range by at least 10 %, at least 20 %, at least 25 %, or at least 30 %, and wherein the device light has a luminous flux in a range from 20 to 200 Im.

[0025] In this connection, the visible wavelength range may be understood as a wavelength range from 400 nm to 780 nm.

[0026] Thereby, improved migraine treatment is obtained.

[0027] The device light may in the second operational mode be green light or greenish white light having a color point of at least 12 standard deviation color matching, SDCM, above the black body locus.

[0028] Thereby, an even further improved migraine treatment is obtained.2024PF80497

[0029] 4

[0030] The controller may further be configured to control, in the first operational mode of the light emitting device, one or more of the correlated color temperature, the intensity, and the color rendering index, CRI, of the white light.

[0031] Thereby tuning of one or more of the CCT, the CRI and the intensity of the white light becomes possible.

[0032] The intensity of the second light source light at the third peak emission wavelength, X3, may be at least two times or at least three times such as at least four times or at least five times higher than the intensity of the first light source light at the first peak emission wavelength, XI, and the intensity of the second light source light at the third peak emission wavelength, X3, may be at least two times or at least three times such as at least four times or at least five times higher, at least six times higher, at least seven times higher, or at least ten times higher, than the intensity of the first light source light at the second peak emission wavelength, X2.

[0033] Thereby high quality device light is provided for in both the first and second operational mode of the light emitting device. The intensity of the second light source light at the third peak emission wavelength, X3, is especially higher than the intensity of the first light source light at the first peak emission wavelength, I, or the first light source light at the second peak emission wavelength, X2, because the third full-width-half-maximum, FWHM3, is relatively narrow-band compared to the first full-width-half-maximum, FWHM1, and the second full-width-half-maximum, FWHM2, which are relatively broad-band. At a same intensity of the spectral peak emissions at the wavelengths XI, X2 and X3, the spectral power contribution of the second light source light (e.g., green) to the total spectral power of the device light would therefore be substantially less than the spectral power contribution of the first light source light (blue and red) to the total spectral power of the device light. Hence, a higher intensity of the second light source light is required, compared to the intensity of the first light source light, to balance out the narrow-band spectral power distribution of the second light source light. In this way, high quality white or greenish white device light can be provided.

[0034] One or more of the following may apply: (i) the first full-width-half-max, FWHM1, is at least 70 nm, at least 75 nm, or at least 80 nm, (ii) the second full-width-half-max, FWHM2, is at least 70 nm, at least 75 nm, or at least 80 nm, and (iii) the third full-width-half-max, FWHM3, is at most 30 nm, at most 25 nm, or at most 20 nm.2024PF80497

[0035] 5

[0036] Thereby an increase in the ratio of the green light to the blue and red light is obtained.

[0037] In the first operational mode, the device light may have one or more of (i) a luminous flux in a range from 20 to 90 Im, and (ii) a CCT in a range from 3700 K to 4300 K. Thereby device light which is perceived by the eye as being equivalent to moonlight is obtained.

[0038] The first solid-state light source may comprise one or more first solid-state emitters, the one or more first solid-state emitters being configured to emit first emitter light having a fourth peak emission wavelength, 4, in a wavelength range from 380 to 450 nm, and a first luminescent element, the first luminescent element comprising (i) a broad-band blue phosphor configured to at least partly convert the first emitter light into the first light source light having the first peak emission wavelength, XI and (ii) a broad-band red phosphor configured to at least partly convert the first emitter light into the first light source light having the second peak emission wavelength, 2.

[0039] The first solid-state light source may comprise one first solid-state emitter, the one first solid-state emitter being configured to emit first emitter light having a fourth peak emission wavelength, 4, in a wavelength range from 380 to 450 nm, and a first luminescent element, the first luminescent element comprising (i) a broad-band blue phosphor configured to at least partly convert the first emitter light into the first light source light having the first peak emission wavelength, XI and (ii) a broad-band red phosphor configured to at least partly convert the first emitter light into the first light source light having the second peak emission wavelength, 2.

[0040] Alternatively, the first solid-state light source may comprise two (or more) first solid-state emitters, the two (or more) first solid-state emitters being configured to emit first emitter light having a fourth peak emission wavelength, 4, in a wavelength range from 380 to 450 nm, and a first luminescent element, the first luminescent element comprising a broadband blue phosphor configured to at least partly convert the first emitter light of a first solid-state emitter of the two solid state emitters into the first light source light having the first peak emission wavelength, I, and a broad-band red phosphor configured to at least partly convert the first emitter light of a second solid-state emitter of the two solid state emitters into the first light source light having the second peak emission wavelength, X2.

[0041] Thereby a highly efficient light emitting device, especially highly efficient in converting the first and second light source light, is provided for. Although in some of the2024PF80497

[0042] 6

[0043] above embodiments the first solid-state light source may comprise a plurality of first solid-state light emitters, these plurality of first solid-state light emitters are controlled as one. That is, the plurality of first solid-state light emitters appear to controller as one first solid-state light source and are controlled by the controller as one first solid-state light source.

[0044] The first luminescent element may comprise a mixture of two phosphors or may comprise two layers each having one of the phosphors. For example, one layer may be arranged on a primary first solid-state emitter, while the other phosphor may be arranged on a secondary first solid-state emitter. Alternatively, the two layers may be stacked.

[0045] The broad-band blue phosphor may be a phosphate phosphor, or a combination of different narrow-band blue phosphors.

[0046] Such phosphors are particularly efficient in converting first emitter light into blue light source light comprised by the first light source light.

[0047] The broad-band red phosphor may be an oxynitride or nitride phosphor, or a combination of different narrow-band red phosphors.

[0048] Such red phosphors are particularly efficient in converting first emitter light into red light source light comprised by the first light source light.

[0049] The different narrow-band blue phosphors or the different narrow-band red phosphors may comprise quantum dots.

[0050] Such phosphors are also very efficient in converting first emitter light into the blue light source light and the red light source light, respectively.

[0051] The second solid-state light source may comprise a blue solid state light source and a third luminescent element, the third luminescent element comprising (a) an organic-inorganic perovskite, OIP, having a FWHM in the range 18-20 nm, or (b) quantum dots with a particle size distribution in the range of 3.5 nm to 4.5 nm, or 3.5 nm to 4 nm.

[0052] Alternatively, the second solid-state light source may comprise a green laser e.g. having a FWHM in the range 1-3 nm.

[0053] The first peak emission wavelength, I, the second peak emission wavelength, X2, and the third peak emission wavelength, X3, may have no mutual overlap.

[0054] The device light may be white light having a color rendering index, CRI, of at least 70, or at least 80.

[0055] The light emitting device may further comprise a sensor configured to sense one or more of an intensity and a correlated color temperature, CCT, of ambient light in a room and to provide the sensed operational parameter to the controller for controlling the first2024PF80497

[0056] 7

[0057] solid state light source and the second solid state light source based on the sensed operational parameter.

[0058] The sensor may further be configured to sense an operational parameter of the light emitting device and to provide the sensed operational parameter to the controller for controlling the first solid state light source and the second solid state light source.

[0059] Thereby, it becomes possible to adapt the obtained device light to various different applications and to the light requirements thereof, and especially to adapt the obtained device light to the ambient light in the room. For instance, it becomes possible to control the correlated color temperature, CCT, and the color rendering index, CRI of the device light.

[0060] The invention further relates to a lamp comprising a light emitting device according to the invention.

[0061] The lamp may further comprise a light transmissive envelope at least partly enclosing the light emitting device and a base for electrically and mechanically connecting the lamp to a socket or a socket of a luminaire.

[0062] The invention still further relates to a luminaire, and especially a nightlight, comprising a lamp according to the invention.

[0063] The invention still further relates to a luminaire, and especially a nightlight, comprising a light emitting device according to the invention.

[0064] It is noted that the invention relates to all possible combinations of features recited in the claims.

[0065] BRIEF DESCRIPTION OF THE DRAWINGS

[0066] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

[0067] Fig. 1 shows a schematic, cross-sectional side view of a light emitting device according to the invention in a first operational mode.

[0068] Fig. 2 shows a schematic, cross-sectional side view of the light emitting device according to Fig. 1 in a second operational mode.

[0069] Fig. 3 shows a schematic, cross-sectional side view of another light emitting device according to the invention in a first operational mode.

[0070] Fig. 4 shows a schematic, cross-sectional side view of the light emitting device according to Fig. 3 in a second operational mode.2024PF80497

[0071] 8

[0072] Fig. 5 shows a schematic, cross-sectional side view of another light emitting device according to the invention in a first operational mode.

[0073] Fig. 6 shows a schematic, cross-sectional side view of the light emitting device according to Fig. 5 in a second operational mode.

[0074] Fig. 7 shows a schematic, cross-sectional side view of another light emitting device according to the invention in a first operational mode.

[0075] Fig. 8 shows a schematic, cross-sectional side view of the light emitting device according to Fig. 7 in a second operational mode.

[0076] Fig. 9 shows a graph of the intensity in arbitrary units as a function of the wavelength of emission (Em; solid line) and excitation (Ex; dashed line), respectively, for a phosphate phosphor.

[0077] Fig. 10 shows a graph of the intensity in arbitrary units as a function of the wavelength of emission (Em; solid line) and excitation (Ex; dashed line), respectively, for a phosphor comprising four different blue quantum dots having a large particle size distribution.

[0078] Fig. 11 shows a graph of the intensity in arbitrary units as a function of the wavelength of emission (Em; solid line) and excitation (Ex; dashed line), respectively, for an oxynitride phosphor.

[0079] Fig. 12 shows a graph depicting the intensity of the device light emitted by a light emitting device according to the invention as a function of the wavelength.

[0080] Fig. 13 shows a schematical side view of a lamp comprising a light emitting device according to the invention.

[0081] Fig. 14 shows a schematical side view of a luminaire comprising a lamp and a light emitting device according to the invention.

[0082] As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.

[0083] DETAILED DESCRIPTION

[0084] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these2024PF80497

[0085] 9

[0086] embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0087] The figures illustrate embodiments operating in their first operational mode and their second operational mode. In the second operational mode, the figures illustrate only the second solid-state light source being ‘on’ while the first solid-state light source is ‘off. This is however in no way limiting the scope of the claimed invention wherein, in the second operational mode, both the first solid-state light source and the second solid-state light source may be ‘on’ but wherein the relative contribution of the second light source light to the total spectral power distribution of the device light is varied. In the second operational mode, the first solid-state light source and the second solid-state light source may be controlled such that the spectral power distribution of the device light varies between white light and green light, with all gradations or shades of greenish white light in between.

[0088] Fig. 1 shows a schematic, cross-sectional side view of a light emitting device 1 according to the invention in a first operational mode, and Fig. 2 shows the light emitting device 1 in a second operational mode. Generally, and irrespective of the embodiment, the light emitting device 1 may be provided as or in a night light configured to provide night lighting, such as dimmed white light.

[0089] Generally, and irrespective of the embodiment, the light emitting device 1 comprises a first solid-state light source 3, a second solid-state light source 5, and a controller 30. The light emitting device 1 is configured to provide, in operation, device light 2.

[0090] The first solid-state light source 3 is configured to provide, in operation, first light source light 4. The first light source light 4 has a first peak emission wavelength, I, in a wavelength range from 420 to 490 nm. The first light source light 4 further comprises a first full-widthhalf-max, FWHM1, of at least 60 nm, or of at least 70 nm. The first light source light 4 further comprises a second peak emission wavelength, X2, in a wavelength range from 600 to 660 nm and having a second full-width-half-maximum, FWHM2, of at least 60 nm.

[0091] The second solid-state light source 5 is configured to provide, in operation, second light source light 6. The second light source light 6 has a third peak emission wavelength, X3, in a wavelength range from 515 to 535 nm. The second light source light 6 further has a third full-width-half-maximum, FWHM3, of at most 35 nm, or of at most 30 nm. The second light source light 6 is thus narrow band green light. The second LED light source 6 may be a LED or a green laser having a FWHM in the range 1-3 nm.2024PF80497

[0092] 10

[0093] The intensity of the second light source light 6 at the third peak emission wavelength, 3, is at least five times higher than the intensity of the first light source light 4 at the first peak emission wavelength, XL The intensity of the second light source light 6 at the third peak emission wavelength, X3, is further at least five times higher than the intensity of the first light source light 4 at the second peak emission wavelength, X2.

[0094] The light emitting device 1 comprises at least a first operational mode (cf. Fig.

[0095] 1) and a second operational mode (cf. Fig. 2). In the first operational mode both of the first solid-state light source 3 and the second solid-state light source 5 are on, or in operation, and emit light. The device light 2 therefore comprises the first light source light 4 and the second light source light 6. The device light 2 is white light. In the second operational mode, only the second solid-state light source 5 is on, or in operation, and emits light, and the device light 2 is the second light source light 6 and thus narrow band green light.

[0096] The controller 30 is configured to individually control the first light source light 4 and the second light source light 6. More particularly, the controller is configured to individually control the first light source light 4 and the second light source light 6 such that the light emitting device 1 comprises at least a first operational mode (cf. Fig. 1) and a second operational mode (cf. Fig. 2).

[0097] In the first operational mode of the light emitting device 1, the device light 2 may be white light having a correlated color temperature, CCT, in a range from 2500 K to 6500 K, or in a range from 3700 K to 4300 K, and having a luminous flux in a range from 20 to 200 Im, or in a range from 20 to 150 Im, or in a range from 20 to 90 Im. In the first operational mode of the light emitting device 1, the device light 2 may further be white light being above the black body locus, BBL, and having a distance of at least 10, or at least 12, standard deviation color matching, SDCM, to the BBL.

[0098] In the second operational mode of the light emitting device 1 the device light 2 is a narrow-band green light comprising the second light source light 6.

[0099] The controller 30 is configured to, in the second operational mode of the light emitting device 1, vary the relative contribution of the second light source light 6 to the total spectral power distribution of the device light 2 in the visible wavelength range by at least 20 %. The device light 2 comprises a luminous flux in a range from 20 to 200 Im.

[0100] The device light 2 is illustrated in Fig. 12 showing a graph depicting the intensity of the device light emitted by a light emitting device according to the invention as a function of the2024PF80497

[0101] 11

[0102] wavelength for each of the first operational mode (dashed line and dotted line) and the second operational mode (dotted line only).

[0103] The controller 30 is further optionally configured to control one or more of the spectral power, the intensity, and the CRI of the white light in the first operational mode of the light emitting device 1. The controller 30 is further optionally configured to control one or more of the spectral power, the intensity, and the CRI by varying the contribution of the narrow-band green light in the second operational mode of the light emitting device 1.

[0104] The light emitting device 1 further comprises an optional sensor 40. The sensor 40 is configured to sense one or more of an intensity and a correlated color temperature, CCT, of ambient light in a room in which the light emitting device 1 is arranged. The sensor 40 is further configured to provide the sensed operational parameter to the controller 30. The controller 30 may then be configured to control the first solid state light source 3 and the second solid state light source 5 based on the received sensed operational parameter.

[0105] The intensity of the white light provided in the first operational mode may be at least five times, at least eight times, or at least ten times, lower than the intensity of the narrow-band green light provided in the second operational mode. The device light 2 provided in the first operational mode may be white light having a color rendering index, CRI, of at least 70, or at least 80.

[0106] Fig. 3 shows a schematic, cross-sectional side view of another light emitting device 100 according to the invention in a first operational mode, and Fig. 4 shows the light emitting device 100 in a second operational mode. The light emitting device 100 differs from the light emitting device 1 shown in Figs. 1 and 2 and described above in virtue of the following features.

[0107] The first solid-state light source 3 comprises a solid-state emitter 31, such as a violet / blue LED, covered by a first luminescent element 9. The solid-state emitter 31 is configured to, in operation, emit emitter light 33. The first luminescent element 9 comprises a broad-band blue phosphor 10. The broad-band blue phosphor 10 may be a phosphate phosphor. The first luminescent element 9 further comprises a broad-band red phosphor 15. The broad-band red phosphor 15 may be an oxynitride or nitride phosphor. The first luminescent element 9 is configured to convert at least a part of the emitter light 33 into the first light source light 4.2024PF80497

[0108] 12

[0109] The device light 2 thus, in the first operational mode of the light emitting device 100, comprises the first light source light 4, the second light source light 6 and optionally unconverted emitter light 33.

[0110] Fig. 5 shows a schematic, cross-sectional side view of another light emitting device 101 according to the invention in a first operational mode, and Fig. 6 shows the light emitting device 101 in a second operational mode. The light emitting device 101 differs from the light emitting device 100 shown in Figs. 3 and 4 and described above in virtue of the following features.

[0111] The first solid-state light source 3 comprises two first solid-state emitters 31, 32, each configured to emit first emitter light 33 having a fourth peak emission wavelength in a wavelength range from 380 to 450 nm. The first solid-state light source 3 further comprises a first luminescent element 9.

[0112] The first luminescent element 9 comprises a broad-band blue phosphor 10 as illustrated at the first solid-state emitter 31. The broad-band blue phosphor 10 may be a phosphate phosphor. Additionally, the first luminescent element 9 comprises a combination of different narrow-band red phosphors 16, 17, 18 as illustrated at the second solid-state emitter 32. The combination of different narrow-band red phosphors 16, 17, 18 may comprise quantum dots having a particle size distribution in the range of 4 nm to 6.5 nm, or 4.5 nm to 6 nm.

[0113] In any event, the first luminescent element 9 is configured to convert at least a part of the first emitter light 33 into first light source light 4. The first light source light 4 forms part of the device light 2.

[0114] The device light 2 thus, in the first operational mode of the light emitting device 101, comprises the first light source light 4, the second light source light 6, and optionally unconverted emitter light 33.

[0115] Fig. 7 shows a schematic, cross-sectional side view of another light emitting device 102 according to the invention in a first operational mode, and Fig. 8 shows the light emitting device 102 in a second operational mode. The light emitting device 102 differs from the light emitting device 101 shown in Figs. 5 and 6 and described above in virtue of the following features.

[0116] The first solid-state light source 3 comprises two first solid-state emitters 31, 32, each configured to emit first emitter light 33 having a fourth peak emission wavelength in2024PF80497

[0117] 13

[0118] a wavelength range from 380 to 450 nm. The first solid-state light source 3 further comprises a first luminescent element 9.

[0119] The first luminescent element 9 comprises a broad-band blue phosphor 10 as illustrated at the first solid-state emitter 31. The broad-band blue phosphor 10 may be a phosphate phosphor. In the embodiment shown, the broad-band blue phosphor 10 comprises a combination of different narrow-band blue phosphors 11, 12, 13. The combination of different narrow-band blue phosphors 11, 12, 13 may comprise quantum dots having a particle size distribution in the range of 1 nm to 3 nm, or 1.5 nm to 3 nm.

[0120] The first luminescent element 9 further comprises a broad-band red phosphor 15 as illustrated at the second solid-state emitter 32. The broad-band red phosphor 15 may be a nitride phosphor or an oxynitride phosphor.

[0121] The second solid-state light source 5 comprises a blue LED 19 and a second luminescent element 20. The second luminescent element 20 comprises an organic-inorganic perovskite, OIP, 21. The OIP 21 comprises a FWHM in the range 18-20 nm. Alternatively, the second luminescent element 20 may comprise quantum dots with a particle size distribution in the range of 3.5 nm to 4.5 nm, or 3.5 nm to 4 nm.

[0122] The third luminescent element 20 is configured to convert at least a part of the light fron blue LED 19 into converted second light source light 61. The converted second light source light 61 comprises a second peak emission wavelength, 2, in a wavelength range from 515 to 535 nm. The converted second light source light 61 further comprises a second full-width-half-maximum, FWHM2, of at most 35 nm, or of at most 30 nm. The converted second light source light 61 is thus narrow band green light. The converted second light source light 61 forms part of the device light 2.

[0123] Referring now to Figs. 9 to 11, different suitable phosphors for a light emitting device 1, 100, 101 according to the invention will be described.

[0124] Phosphate class

[0125] Generally, phosphors of the phosphate class are suitable for use as a luminescent material or phosphor of the first luminescent element 9.

[0126] Phosphors of the phosphate class, or simply phosphate phosphors, are luminescent materials comprising a phosphate, PO4.2024PF80497

[0127] 14

[0128] Fig. 9 shows a graph of the intensity in arbitrary units as a function of the wavelength of emission (Em; solid line) and excitation (Ex; dashed line), respectively, for a phosphate phosphor.

[0129] Fig. 10 furthermore shows a graph of the intensity in arbitrary units as a function of the wavelength of emission (Em; solid line) and excitation (Ex; dashed line), respectively, for a phosphor comprising four different blue quantum dots having a large particle size distribution. Generally, such phosphors are also suitable for use as a luminescent material or phosphor of the first luminescent element 9.

[0130] (oxy)nitride class

[0131] Luminescent material comprising NfcSis Eu2, or MAlSiMvEu2or Ca2AlSi3O2Ns:Eu2+, etc., wherein M comprises one or more of Ba, Sr, and Ca, especially in embodiments at least Sr. Hence, in embodiments, the luminescent may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “:Eu”, indicates that part of the metal ions is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSi Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3. Divalent europium will in general replace divalent cations, such as the above divalent alkaline earth cations, especially 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); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Further, the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as NfcSis Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and / or Ba. In a further specific embodiment, M consists of Sr and / or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSisNs Eu (i.e. 75 % Ba; 25% Sr). Here, Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca). Likewise, the material (Ba,Sr,Ca)AlSiN3:Eu2024PF80497

[0132] 15

[0133] can also be indicated as MAlSi Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art.

[0134] Fig. 11 shows a graph of the intensity in arbitrary units as a function of the wavelength of emission (solid line) and excitation (dashed line), respectively, for an oxynitride phosphor. Oxynitride phosphors can be used to package high CRI LEDs which require full spectrum coverage. Dominant emission wavelengths range from 500 nm to 650 nm. Oxynitride phosphors are particularly suitable for use as a part of or all of the second luminescent material 14.

[0135] Another type of phosphors being suitable for use as a luminescent material or phosphor of the second luminescent element 14 is a phosphor comprising different red quantum dots having a large particle size distribution.

[0136] Fig. 13 shows an exemplary lamp 300 comprising a light emitting device 1, 100, 101, 102 according to any embodiment of the invention. In the embodiment shown, the light emitting device 1, 100, 101, 102 is provided in the form of a substantially straight light emitting device. The light emitting device may in other embodiments be a light emitting device with another shape, such as, but not limited to, spiral-shaped, helix-shaped, meandering, twisted, flat and combinations thereof.

[0137] The lamp 300 further comprises a driver or controller 305 configured for controlling the solid-state light sources 3, 5 of the light emitting device 1, 100, 101, 102. The controller 305 is configured to power the plurality of solid-state light sources 3, 5 via electrical circuitry (not visible on the figures) of the light emitting device 1, 100, 101, 102. The light emitting device 1, 100, 101, 102 may also comprise a controller 30, which may or may not be separate from the controller 305. In other words, the controller 305 and the controller 30 of the light emitting device 1, 100, 101, 102 may be integrated into one and the same driver or controller, or they may be mutually separate units.

[0138] The lamp 300 further comprises an envelope 301 at least partially enveloping the at least one light emitting device 1, 100, 101, 102. The lamp 300 further comprises a cap 303. As shown in Fig. 13, the controller 305 is arranged within the envelope 301. When comprising a cap 303, the controller 305 may also be arranged inside the cap 303 such that it2024PF80497

[0139] 16

[0140] is hidden from view. The lamp 300 further comprises threading 302 for connection to a socket, and a terminal 304 for connection to a source of electrical energy.

[0141] The envelope 301 of the lamp 300 may further and optionally be provided with a coating (not shown), such as a reflective coating, covering at least a part of the envelope 301.

[0142] Turning finally to Fig. 14, an exemplary luminaire in the form of a pendant 400 is shown. The pendant 400 comprises a light emitting device 1, 100, 101, 102 according to any embodiment of the invention. The light emitting device 1, 100, 101, 102 is as shown in Fig. 13 provided within a lamp 300 in the form of a light bulb. The light emitting device 1, 100, 101, 102 as shown in Fig. 14 is a substantially straight light emitting device.

[0143] As is also mentioned above, the light bulb further comprises a transparent envelope (cf. transparent envelope 301 of lamp 300) at least partially enveloping the at least one light emitting device 1, 100, 101, 102. The transparent envelope may be shaped in any feasible shape, for example such as to resemble the shape of any one of a standard light bulb, a globe light bulb, a candlelight bulb, a customized light bulb and even a spiral light bulb. The transparent envelope may comprise a luminescent material. The transparent envelope may be a glass envelope.

[0144] The pendant 400 further comprises a socket 401 for connecting the lamp 300, and thereby the light emitting device 1, 100, 101, 102, to the pendant 400. The socket 401 is adapted to cooperate with the base 303 of the lamp 300. The socket 401 may comprise a threading adapted to cooperate with the threading 302 of the lamp 300. The socket 401 may comprise a terminal adapted to cooperate with the terminal 304 of the lamp 300. The pendant 400 further comprises a reflector or screen 403.

[0145] The pendant 400 may further comprise a driver 402 configured for controlling the light emitting device 1, 100, 101, 102. The driver 402 may or may not be the same unit as the controller 305 described above. In other words, the driver 402 and the controller 305 may be integrated into one and the same driver or controller, or they may be mutually separate units. Alternatively, or additionally, the light emitting device 1, 100, 101, 102 may also comprise a controller 30, which may or may not be separate from one or both of the driver 402 and the controller 305.

[0146] As shown in Fig. 14, the driver 402 is arranged on a reflector or screen 403 of the pendant 400. The driver may also be arranged within or incorporated into the reflector or2024PF80497

[0147] 17

[0148] screen 403. The pendant 400 further comprises an electrical wiring 404 for connection to a source of electricity, such as a mains.

[0149] It is noted that the pendant 400 shown in Fig. 14 is only one example of a luminaire according to the invention. Any suitable type of luminaire may be envisaged, such as but not limited to, a standing luminaire, a wall hung luminaire, a chandelier, a reading luminaire, an outdoor luminaire, and a table luminaire.

[0150] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0151] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Claims

2024PF8049718CLAIMS1. A light emitting device (1) configured to provide, in operation, device light (2), the light emitting device comprising:a , (b) (3) configured to provide, in operation, first light source light (4) having a first peak emission wavelength, I, in a wavelength range from 420 to 490 nm and having a first full-width-half-max, FWHM1, of at least 60 nm, and a second peak emission wavelength, X2, in a wavelength range from 600 to 660 nm and having a second full-widthhalf-maximum, FWHM2, of at least 60 nm;a second solid-state light source (5) configured to provide, in operation, second light source light (6) having a third peak emission wavelength, X3, in a wavelength range from 515 to 535 nm and having a third full-width-half-maximum, FWHM3, of at most 35 nm; and a controller (30) configured to individually control the first solid-state light source (3) and the second solid-state light source (5); wherein,in a first operational mode of the light emitting device (1), the controller (30) is configured to control the first solid-state light source (3) and the second solid-state light source (5) such that the device light (2) comprises the first light source light (4) and the second light source light (6), and the device light (2) is white light having a correlated color temperature, CCT, in a range from 2500 K to 6500 K and a luminous flux in a range from 20 to 250 Im.

2. A light emitting device according to claim 1, wherein the controller (30) in a second operational mode of the light emitting device (1) is configured to increase the relative contribution of the second light source light (6) to the total spectral power distribution of the device light (2) in the visible wavelength range by at least 10 %, and wherein the device light (2) has a luminous flux in a range from 20 to 200 Im.

3. A light emitting device according to claim 2, wherein the device light (2) in the second operational mode is green light or white light having a color point of at least 12 standard deviation color matching, SDCM, above the black body locus.2024PF80497194. A light emitting device according to any one of the preceding claims, wherein the controller (30) further is configured to control, in the first operational mode of the light emitting device (1), one or more of the correlated color temperature, the intensity, and the color rendering index, CRI, of the white light.

5. A light emitting device according to any one of the above claims, wherein (i) the intensity of the second light source light (6) at the third peak emission wavelength, X3 is at least two times, preferably at least five time, higher than the intensity of the first light source light (4) at the first peak emission wavelength, I, and (ii) the intensity of the second light source light (6) at the third peak emission wavelength, X3 is at least two times, preferably at least five times, higher than the intensity of the first light source light (4) at the second peak emission wavelength, X2.

6. A light emitting device according to any one of the above claims, wherein the following applies:the first full-width-half-max, FWHM1, is at least 70 nm,the second full-width-half-max, FWHM2, is at least 70 nm, and the third full-width-half-max, FWHM3, is at most 30 nm.

7. A light emitting device according to any one of the above claims, wherein, in the first operational mode, the device light (2) having one or more of (i) a luminous flux in a range from 20 to 90 Im, and (ii) a CCT in a range from 3700 K to 4300 K.

8. A light emitting device according to any one of the above claims, wherein the first solid-state light source (3) comprises one or more first solid-state emitters (31, 32) configured to emit first emitter light (33) having a fourth peak emission wavelength in a wavelength range from 380 to 450 nm, and a first luminescent element (9), the first luminescent element comprising (i) a broad-band blue phosphor (10) configured to at least partly convert the first emitter light (33) into the first light source light (4) having the first peak emission wavelength, XI and (ii) a broad-band red phosphor (15) configured to at least partly convert the first emitter light (33) into the first light source light (4) having the second peak emission wavelength, X2.2024PF80497209. A light emitting device according to claim 8, wherein the broad-band blue phosphor (10) is a phosphate phosphor, or a combination of different narrow-band blue phosphors (11, 12, 13).

10. A light emitting device according to claim 8 or 9, wherein the broad-band red phosphor (15) is an oxynitride or nitride phosphor, or a combination of different narrow-band red phosphors (16, 17, 18).

11. A light emitting device according to claim 9 or 10, wherein the different narrow-band blue phosphors (11, 12, 13) or the different narrow-band red phosphors (16, 17, 18) comprises quantum dots.

12. A light emitting device according to any one of the above claims, wherein the second solid-state light source (5) comprises:(i) a blue LED (19) and a second luminescent element (20), the second luminescent element comprising (a) an organic-inorganic perovskite, OIP, (21) having a FWHM in the range 18-20 nm, or (b) quantum dots with a particle size distribution in the range of 3.5 nm to 4.5 nm, or 3.5 nm to 4 nm, or(ii) a green laser having a FWHM in the range 1-3 nm.

13. A light emitting device according to any one of the above claims, wherein the first peak emission wavelength, I, the second peak emission wavelength, X2, and the third peak emission wavelength, X3, have no mutual overlap.

14. A light emitting device according to any one of the above claims, further comprising a sensor (40) configured to sense one or more of an intensity and a correlated color temperature, CCT, of ambient light in a room in which the lighting emitting device is arranged and to provide the sensed operational parameter to the controller (30) for controlling the first solid state light source (3) and the second solid state light source (5) based on the sensed operational parameter.

15. A lamp (300) or a luminaire (400) or a nightlight comprising a light emitting device (1) according to any one of the preceding claims.

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