LED lighting device with phosphor layer mixture

Abstract

There is provided a LED lighting device (100) providing LED light source light (110), and comprising a carrier (120) and LED chips (130). Each LED chip comprises LED(s) (140) and a phosphor layer (150) converting emitted LED light. The LED chips comprises (a) first LED chip(s) (160) emitting light with a peak emission wavelength (PEW) within 430 – 450 nm, (a) second LED chip(s) (170) emitting light with a PEW within 445 – 465 nm, and (a) third LED chip(s) (180) emitting light with a PEW within 465 – 480 nm. The phosphor layer comprises a first phosphor material (190) emitting light with a PEW within 535 – 545 nm, a second phosphor material (200) emitting light with a PEW within 600 – 615 nm, a third phosphor material (210) emitting light with a PEW within 640 – 655 nm, and a fourth phosphor material (220) emitting light with a PEW within 650 – 680 nm.

Description

[0001] LED LIGHTING DEVICE WITH PHOSPHOR LAYER MIXTURE

[0002] FIELD OF THE INVENTION

[0003] The present invention generally relates to a light emitting diode, LED, lighting device. More specifically, the present invention relates to a LED lighting device comprising a plurality of LED chips and a phosphor layer mixture.

[0004] BACKGROUND OF THE INVENTION

[0005] The use of light emitting diodes, LEDs, for illumination purposes continues to attract attention. Compared to incandescent lamps, fluorescent lamps, neon tube lamps, etc., LEDs provide numerous advantages such as a longer operational life, a reduced power consumption, and an increased efficiency related to the ratio between light energy and heat energy.

[0006] The requirements for LED devices, fixtures and arrangements, e.g., LED displays, continue to increase. For example, there is a wish to improve the color rendering index, CRI, but it will be appreciated that improving the CRI is particularly difficult for relatively large index values, such as CRI > 95.

[0007] The spectrum combining fluorescent emitted light and excite light is usually depressed in a blue-green region. Traditional blue light chips are generally unable to resolve defects in the blue-green region, and a combination scheme of e.g., two blue LED chips has a relatively low spectral fit in the blue light region. Certainly, by providing more blue LED chips, the closer the LED spectrum is to the reference spectrum in a short wavelength range. However, with the increase of blue LED chip bands used, the difficulty of achieving mass production becomes higher. In addition, the excitations bands of fluorescent material (e.g., powder) and blue light need to be matched, and the use of fluorescent material also affects mass production.

[0008] Based on the above, it is desired to provide LED devices which even further improve the performance, functionality and / or appearance of LED light, and in particular the CRI thereof, whilst still facilitating mass production of such LED devices.

[0009] US 2021131618A1 discloses a light emitting device includes photoluminescence materials which generate light with a peak emission wavelength in a range 490 nm to 680 nm (green to red) and a broadband solid-state excitation source operable to generate broadband blue excitation light with a dominant wavelength in a range from 420 nm to 470 nm.

[0010] US 2021013185A1 discloses a light emitting device includes photoluminescence materials which generate light with a peak emission wavelength in a range from about 490 nm to about 680 nm; and a broadband solid-state excitation source operable to generate broadband excitation light with a dominant wavelength in a range from about 420 nm to about 480 nm.

[0011] US 2020357962A1 discloses a white light-emitting device including a semiconductor LED chip that emits a violet wavelength range of light with an emission peak at 380 nm to 430 nm, and a phosphor layer distributed in a transparent resin layer that emits light when excited by an excitation wavelength of the violet LED chip.

[0012] SUMMARY OF THE INVENTION

[0013] It is of interest to explore the possibility of combining one or more of the numerous advantages of LEDs, whilst improving the performance, functionality and / or appearance of the LED light, and in particular the CRI thereof, emitted from such LED devices as well as facilitating mass production of these LED devices.

[0014] This and other objects are achieved by providing a LED device having the features in the independent claim. Preferred embodiments are defined in the dependent claims.

[0015] Hence, according to the present invention, there is provided a light emitting diode, LED, lighting device configured to provide, during operation, LED light source light. The LED lighting device comprises a carrier and a plurality of LED chips mounted on the carrier. Each LED chip of the plurality of LED chips comprises at least one LED configured to emit LED light, and a phosphor layer configured to at least partially convert the emitted LED light. The plurality of LED chips comprises at least one first type LED chip configured to emit light with a peak emission wavelength, i, in a first blue wavelength range, IB, of 430 - 450 nm, at least one second type LED chip configured to emit light with a peak emission wavelength, Xz, in a second blue wavelength range, XZB, of 445 - 465 nm, and at least one third type LED chip configured to emit light with a peak emission wavelength, 3, in a third blue wavelength range, 3B, of 465 - 480 nm. Furthermore, the phosphor layer comprises a mixture of a first phosphor material configured to emit converted light with a peak emission wavelength, kip, in a first wavelength range, ie, of 535 - 545 nm, a second phosphor material configured to emit converted light with a peak emission wavelength, p, in a second wavelength range, fc, of 600 - 615 nm, a third phosphor material configured to emit converted light with a peak emission wavelength, fap, in a third wavelength range, fac, of 640 - 655 nm, and a fourth phosphor material configured to emit converted light with a peak emission wavelength, fap, in a first wavelength range, fac, of 650 - 680 nm.

[0016] Thus, the present invention is based on the idea of providing a LED lighting device comprising various types of LED chips configured to emit light with a peak emission wavelength within various blue wavelength ranges. Furthermore, each LED chip comprises a phosphor layer comprising a mixture of various phosphor materials configured to emit converted light with a peak emission wavelength within various wavelength ranges. By said combination of various types of LED chips and a mixture of various phosphor materials, the performance and / or functionality of the LED lighting device, as well as the appearance and / or the decorative aspect thereof, are improved.

[0017] The present invention is advantageous in that it provides for a LED lighting device comprising various types of LED chips, emitting LED light with peak emission wavelengths within various blue wavelength ranges. This fills the spectral gap in light emitted from traditional LED lighting devices, which is usually depressed in the blue-green wavelength region. As a result, the color rendering index, CRI, may be increased. Furthermore, the peak value of emitted blue light in the spectral emission of the provided LED light source light may be reduced. Reducing the peak value of blue light may be beneficial for health and comfort of a user, as well as performance in various applications such as improving visual performance by reducing glare, improving color rendering, and / or improving contrast for various devices with monitors and screens. It will be appreciated that a prolonged exposure to blue light may cause eye strain and may contribute to retinal damage over time. Lowering the peak value of blue light may also create a more pleasant and inviting lighting environment. It should be noted that the various types of LED chips provide for an improved fitting degree between spectral characteristics of the blue light emitted by the LED lighting device and the blue light portion of an ideal blackbody radiation spectrum.

[0018] The present invention is further advantageous in that the at least one second type LED chip is configured to emit light with a peak emission wavelength, fa, in a second blue wavelength range, fas, of 445 - 465 nm. This blue wavelength range is chosen to further fill spectral gaps in light emitted from traditional LED lighting devices, which is usually depressed in the blue-green wavelength region. In other words, the present invention provides for a more continuous and balanced emission spectrum. The quality of the emitted LED light source light may be improved in terms of enhanced perception of objects, and / or an increased color rendering index, CRI.

[0019] It should be noted that the phosphor layer comprises a mixture of a first, a second, a third, and a fourth phosphor material configured to emit converted light with a peak emission wavelength within various wavelength ranges. The provided mixture of phosphor materials enables an improved fitting degree between spectral characteristics of the blue light emitted by the LED lighting device and the blue light portion of an ideal blackbody radiation spectrum.

[0020] The present invention is further advantageous in that the LED lighting device of the present invention overall comprises relatively few components. The relatively low number of components is advantageous in that the LED lighting device is relatively inexpensive to fabricate. Moreover, the low number of components of the LED lighting device implies an easier recycling, especially compared to devices or arrangements comprising a relatively high number of components which impede an easy disassembling and / or recycling operation. Also, the relatively few components facilitate for mass production of the LED lighting device.

[0021] Especially, the present invention comprises relatively few LED chips, as well as relatively few phosphor materials. Hence, the present invention provides a LED lighting device which can accurately deliver light according to different lighting needs, requirements and / or desired settings, whilst also maintaining a relatively uncomplicated construction of the lighting device. The complexity of matching the excitation bands of phosphor materials with emitted LED light from the LEDs increases together with the amount of various phosphor materials and various LEDs used. Hence, the present invention further facilitates mass production, making it less complex.

[0022] There is provided a LED lighting device comprising a carrier and a plurality of LED chips mounted on the carrier. The LED lighting device may be arranged in a straight configuration or in a non-straight configuration such as for example a curved configuration, a 2D / 3D spiral, or a helix. The carrier may, for instance, be a substrate, which may be rigid (made from e.g., a polymer, glass, quartz, metal, or sapphire) or flexible (e.g., made of a polymer or metal e.g., a film or foil). The carrier may be reflective or light transmissive, such as translucent or transparent. Each LED chip comprises at least one LED configured to emit LED light, and a phosphor layer configured to at least partially convert the emitted LED light, wherein phosphor layer comprises a mixture of various phosphor materials. By “phosphor materials”, it is here meant a material, composition, and / or substance which is phosphorescent and configured to affect light in such a manner that at least some light can pass through the phosphorescent material. By “at least partially convert”, it is here meant that the phosphor layer may be configured to convert only a portion of the emitted LED light, or all the emitted LED light. Furthermore, the plurality of LED chips comprises various types of LED chips configured to emit light with various peak emission wavelengths ( i, h, ta) in various blue wavelength ranges ( IB, tan. tan). Also, the phosphor materials are configured to emit converted light with a peak emission wavelength (kip, p, tap) in various wavelength ranges (tac, tac, tac). The “peak emission wavelength” may alternatively be denoted “dominant peak emission wavelength”.

[0023] According to an embodiment of the present invention, the phosphor layer may cover the plurality of LED chips. Hence, the phosphor layer may cover, enclose, encompass, or the like the plurality of LED chips. The present embodiment is advantageous in that the phosphor layer may (completely, or almost completely) cover the plurality of LED chips. This enables an improved color consistency and / or uniform excitation and emission. In comparison to remote phosphor layers, the present embodiment is in no need of additional optics or light mixing structures, allowing for a simplified design.

[0024] According to an embodiment of the present invention, the phosphor layer may only cover each LED chip of the plurality of LED chips. In other words, in the present embodiment, the phosphor layer may not cover the carrier. The present embodiment is advantageous in that the phosphor layer may be arranged in closer proximity to each LED chip. This enables efficient excitation, by the emitted LED light, of the excitation bands of the phosphor materials. Furthermore, the present embodiment allows for unform excitation, resulting in consistent emission. In addition, a shorter distance between each LED chip and the phosphor layer, as well as less reflection interfaces, may result in reduced light loss during conversion.

[0025] According to an embodiment of the present invention, the phosphor layer may cover the plurality of LED chips and at least a portion of the carrier. Hence, the phosphor layer may cover the plurality of LED chips together with covering only a portion of the carrier or all of the carrier. The present embodiment is advantageous in that it allows for an improved color blending due to the possibility of interaction with surrounding materials, such as with the carrier. Additionally, the present embodiment enables design flexibility, and facilitates for creative arrangements and light distribution. According to an example, the phosphor layer covers the plurality of LED chips and a first major surface of the carrier. According to another example, the phosphor layer covers the plurality of LED chips, a first major surface of the carrier, and a second major surface of the carrier.

[0026] According to an embodiment of the present invention, the phosphor layer may constitute a coating. In other words, each LED chip of the plurality of LED chips may comprise a phosphor coating configured to at least partially convert the emitted LED light. The coating may be applied to the LED chips as a thin film or covering. The present embodiment is advantageous in that the coating may serve as a physical barrier, protection, boundary, or the like, to components of the LED lighting device sensitive to mechanical damage, dust, moisture, contaminants, or the like. Such components may be the at least one LED configured to emit LED light. The phosphor layer constituting a coating may also facilitate manufacturing of the LED lighting device. The phosphor coating may be applied to the LED lighting device using various methods, such as dipping, spraying, dispensing, and / or printing. Additionally, properties of the phosphor coating may more easily be adjusted, such as ratio and thickness of the various phosphor materials.

[0027] According to an embodiment of the present invention, the LED lighting device may comprise an encapsulant covering at least a portion of the carrier and covering at least a portion of the plurality of LED chips, wherein the encapsulant comprises the phosphor layer. Hence, the encapsulant may cover only a portion of the carrier, or all of the carrier. Also, the encapsulant may cover only a portion of the plurality of LED chips, or all of it. By “encapsulant”, it is here meant a material, element, arrangement, or the like, which is configured or arranged to cover, surround, encapsulate, and / or enclose at least a portion of the carrier and cover, surround, encapsulate, and / or enclose at least a portion of the plurality of LED chips. The present embodiment is advantageous in that the encapsulant may function as a barrier, shield, blockade, cover, or the like to components of the LED lighting device sensitive to environmental factors, such as moisture, dust, damaging chemicals, mechanical damage, etc. Such sensitive components may be the at least one LED configured to emit LED light. The protective encapsulant may thus increase safety of the LED lighting device during handling and assembly. The operational lifespan and / or reliability of consistent performance of the LED lighting device may also be improved. Additionally, introducing an encapsulant comprising the phosphor layer enables an increased flexibility in design of the LED lighting device, for example complex shapes and sizes. Hence, the embodiment provides a LED lighting device which can accurately deliver light according to different lighting needs, requirements and / or desired settings whilst also maintaining a relatively uncomplicated construction of the lighting device. According to an embodiment of the present invention, a distribution ratio of the first type of LED chips, the second type of LED chips, and the third type of LED chips may be 6-8 : 8-10 : 7-9. Hence, the distribution ratio of the amount of the first, second, and third types of LED chips may be according to 6-8 : 8-10 : 7-9, wherein 7 : 9 : 8 may represent a particularly desirable distribution ratio. The present embodiment is advantageous in that the distribution ratio of the various types of LED chips may provide for an even further improved fitting degree between spectral characteristics of the blue light emitted by the LED lighting device and the blue light portion of an ideal blackbody radiation spectrum. Thus, the present distribution ratio may improve the perception of objects, and / or an increased CRI.

[0028] According to an embodiment of the present invention, a distribution of the first type of LED chips, the second type of LED chips, and the third type of LED chips may be uniform. Hence, the first, second, and third type of LED chips may be mounted on the carrier in a uniform arrangement. By the distribution of the types of LED chips being uniform, it is here meant that the distribution is e.g. constant, consistent, regular, etc. The present embodiment is advantageous in that it facilitates an even light distribution. This may reduce hotspots and / or dark spots, resulting in a smoother and more consistent light output. Additionally, the uniform arrangement may improve thermal management by more effectively spreading out generated heat. Hence, the present embodiment may increase the overall thermal performance and / or longevity of the LED chips.

[0029] According to an embodiment of the present invention, at least one of the mass percentage of the first phosphor material, mpi, is in a range of 70 - 92 %, the mass percentage of the second phosphor material, mp2, is in a range of 3 - 15 %, the mass percentage of the third phosphor material, mp3, is in a range of 0.25 - 5 %, and the mass percentage of the fourth phosphor material, mp4, is in a range of 0.25 - 5 %, may be fulfilled. The present embodiment is advantageous in that it enables an increased fitting between the excitation bands of the phosphor materials and the emitted LED light. Thus, the embodiment may provide a LED lighting device with increased absorption by the phosphor layer. In other words, the embodiment allows for a more efficient conversion between the emitted LED light, by the at least one LED, to converted light, by the phosphor layer. Moreover, potential energy loss caused by said conversion may be reduced. The increased fitting between the excitation bands of the phosphor materials and the emitted LED light may also provide a LED light device with an increased luminous efficacy.

[0030] According to an embodiment of the present invention, at least one of the mass percentage of the first phosphor material, mpi, is in a range of 80 - 90 %, the mass percentage of the second phosphor material, mp2, is in a range of 5 - 10 %, the mass percentage of the third phosphor material, mp3, is in a range of 0.5 - 2 %, and the mass percentage of the fourth phosphor material, mp4, is in a range of 0.5 - 2 %, may be fulfilled. The present embodiment is advantageous in that the fitting, matching, pairing, or the like of the excitation bands of the phosphor materials and the emitted LED light may be further improved. Hence, the embodiment provides a LED lighting device which can deliver light according to different lighting needs, requirements and / or desired settings with an increased accuracy, whilst also maintaining a relatively uncomplicated construction of the lighting device.

[0031] According to an embodiment of the present invention, the LED light source light may have a color rendering index, CRI, in a range of 97 - 99. The present embodiment is advantageous in that it provides a LED lighting device which is able to deliver LED light source light with an improved color accuracy. Consequently, visual comfort may be improved for a user, as well as performance in various applications where color rendering is of high importance, such as art, design, and / or medical fields. It should be noted that the present embodiment provides a LED lighting device with a relatively high CRI, whilst maintaining a relatively uncomplicated construction of the lighting device. Hence, the present embodiment adapts a desirable balance between providing a high-quality LED lighting device and enabling a manufacturing, handling, and / or assembling approach which is relatively uncomplicated.

[0032] According to an embodiment of the present invention, the LED light source light may have a color point within 3 standard deviation of color matching, SDCM, from the black body locus, BBL. In other words, the LED light source light exhibits color characteristics relatively close to the ideal color temperatures represented by the BBL. The present embodiment is advantageous in that it provides uniform LED light source light which allows for natural-looking illumination. This may entail an increased light experience for users.

[0033] According to an embodiment of the present invention, the LED lighting device may comprise a controller configured to control the luminous flux of the LED light source light. By the term “controller”, it is here meant a control unit, device, arrangement, or the like, functional of controlling the luminous flux of the LED light source light either by wire or via wireless technology. The present embodiment is advantageous in that it allows for an enhanced control of the LED lighting device. Additionally, the present embodiment facilitates the control of the LED lighting device for a user. According to an embodiment of the present invention, the controller may be coupled to, and configured to individually control, each type of LED chip of the at least one first type LED chip, the at least one second type LED chip, and the at least one third type LED chip. For example, the controller may be configured to control one type of the plurality of LED chips to deliver a relatively high luminous flux, and another type of the plurality of LED chips to deliver a relatively low luminous flux. This entails the LED lighting device to be adaptable to different lighting needs and / or desires regarding e.g., a provision of light to a specific area in a larger space wherein the LED lighting device is arranged.

[0034] According to an embodiment of the present invention, there is provided a LED lamp, comprising the LED lighting device described herein, a light-transmissive envelope at least partly enclosing the LED lighting device, and a connector for electrically and mechanically connecting the LED lamp to a socket of a luminaire. The present embodiment is advantageous in that the LED lighting device, comprising the plurality of LED chips, combines the aspects of a desired light emission and aesthetical appearance provided via the LED lighting device and / or via the feature(s) of the lamp.

[0035] Further objectives of, features of, and advantages with, the present invention will become apparent when studying the following detailed disclosure, the drawings, and the appended claims. Those skilled in the art will realize that different features of the present invention can be combined to create embodiments other than those described in the following.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Fig. 1 schematically shows a LED lighting device according to an exemplifying embodiment of the present invention,

[0039] Fig. 2 schematically shows a LED lighting device according to an exemplifying embodiment of the present invention,

[0040] Fig. 3 schematically shows a LED lamp comprising a LED lighting device according to an exemplifying embodiment of the present invention, and

[0041] Figs. 4-8 shows diagrams illustrating emission intensity against corresponding wavelength for reference values, a prior art solution, and a LED lighting device according to exemplifying embodiments of the present invention. DETAILED DESCRIPTION

[0042] The present invention will now be described more fully hereinafter with reference to the accompanying figures, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0043] Fig. 1 schematically shows a LED lighting device 100 according to an exemplifying embodiment of the present invention.

[0044] The LED lighting device 100 of Fig. 1 is configured to provide (emit), during operation, LED light source light 110. The LED light source light 110 may be white light (broad-spectrum light) having a correlated color temperature, CCT, in a range of 1700K- 6500K, and a color rendering index, CRI, of at least 80. The LED lighting device 100 comprises a carrier 120 and a plurality of LED chips 130 mounted on the carrier 120. The carrier 120 may, for instance, be a substrate, which may be rigid (made from e.g., a polymer, glass, quartz, metal, or sapphire) or flexible (e.g., made of a polymer or metal e.g., a film or foil). The carrier 120 may be reflective or light transmissive, such as translucent or transparent. The shape of the carrier 120 of Fig. 1 is rectangular, but other shapes are equally applicable, such as a circular shape.

[0045] According to Fig. 1, the plurality of LED chips 130 is mounted on a first major surface of the carrier 120. It should be noted that at least one LED chip 130 of the plurality of LED chips 130 may be arranged on a second major surface (not shown) of the carrier 120, opposite the first major surface of the carrier 120. Each LED chip 130 of the plurality of LED chips 130 comprises at least one LED 140 configured to emit LED light. As shown in Fig. 1, each LED chip 130 of the plurality of LED chips 130 comprises (exactly) one LED 140, but any number of LEDs 140 is viable.

[0046] Furthermore, each LED chip 130 of the plurality of LED chips 130 comprises a phosphor layer 150 configured to at least partially convert the emitted LED light. The phosphor layer 150 for each LED chip 130 of the plurality of LED chips 130 may be a continuous layer for all of the plurality of LED chips 130, as shown in Fig. 1, or individual / separated layers for at least two LED chips 130 of the plurality of LED chips 130. Although not shown, a thickness of the phosphor layer 150 may vary over a length and / or a width of the LED lighting device 100. The plurality of LED chips 130 comprises at least one first type LED chip 160 configured to emit light with a peak emission wavelength, ta, in a first blue wavelength range, IB, of 430 - 450 nm, at least one second type LED chip 170 configured to emit light with a peak emission wavelength, ta, in a second blue wavelength range, XZB, of 445 - 465 nm, and at least one third type LED chip 180 configured to emit light with a peak emission wavelength, ta, in a third blue wavelength range, tas, of 465 - 480 nm. Hence, the LED lighting device 100 may comprise the same or different numbers of the first, second, and / or third type LED chips 160, 170, 180. As shown in Fig. 1, the LED lighting device 100 comprises (exactly) one first type LED chip 160, (exactly) one second type LED chip 170, and (exactly) one third type LED chip 180. It should also be noted in Fig. 1 that the plurality of LED chips 130 is uniformly arranged, distributed, or the like along a length direction of the carrier 120. However, other (non-uniform) distribution patterns of the plurality of LED chips 130 are possible.

[0047] Furthermore, the phosphor layer 150 comprises a mixture of a first phosphor material 190 configured to emit converted light with a peak emission wavelength, kip, in a first wavelength range, tac, of 535 - 545 nm, a second phosphor material 200 configured to emit converted light with a peak emission wavelength, p, in a second wavelength range, tac, of 600 - 615 nm, a third phosphor material 210 configured to emit converted light with a peak emission wavelength, tap, in a third wavelength range, tac, of 640 - 655 nm, and a fourth phosphor material 220 configured to emit converted light with a peak emission wavelength, tap, in a first wavelength range, tac, of 650 - 680 nm. In other words, the phosphor layer 150 comprising the mixture of various phosphor materials 190, 200, 210, 220 is configured to convert at least a portion of emitted LED light from the LEDs 140 of the plurality of LED chips 130 into converted light with a peak emission wavelength kip, tap, tap, tap in a blue wavelength range tac, tac, tac, tac, respectively.

[0048] Hence, the phosphor layer 150 comprises a mixture, combination, composition, blending, or the like of the first phosphor material 190, the second phosphor material 200, the third phosphor material 210, and the fourth phosphor material 220. Each phosphor material 190, 200, 210, 22 may comprise more than one phosphor substance in order to provide (emit) converted light within the associated wavelength range tac, tac, tac, tac. Although not shown in Fig. 1, a concentration of the various phosphor materials 190, 200, 210, 220 of the mixture of the phosphor layer 150 may be different to each other. Also, the concentration of the various phosphor materials 190, 200, 210, 220 may vary over a length, a width, and / or a thickness of the LED lighting device 100. The various phosphor materials 190, 200, 210, 220 may be uniformly dispersed within the phosphor layer 150. The various phosphor materials 190, 200, 210, 220 may comprise for example BOSE phosphor, phosphate phosphor, LuAG phosphor, YAG phosphor, BSSN phosphor, KSiF phosphor, nitride phosphor, and / or oxynitride phosphor.

[0049] Furthermore, at least a portion of emitted LED light from each at least one LED 140 is converted by the phosphor layer 150. Thus, the provided (emitted) LED light source light 110 from the LED lighting device 100 comprises at least a portion of converted light from the various phosphor materials 190, 200, 210, 220. Nonetheless, the provided LED light source light 110 may also comprise at least a portion of the (non-converted) emitted LED light from the LEDs 140 of the plurality of LED chips 130. Hence, the provided LED light source light 110 may comprise at least a portion of emitted LED light by the LEDs 140 and at least a portion of converted light by the phosphor layer 150.

[0050] Fig. 2 schematically shows a LED lighting device 100 according to an exemplifying embodiment of the present invention. It should be noted that the LED lighting device 100 shown in Fig. 2 has several features in common with the LED lighting device 100 shown in Fig. 1, and some references have been omitted in Fig. 2 for this reason. It is hereby referred to Fig. 1 and the associated text for an increased understanding of some of the features and / or functions of the LED lighting device 100.

[0051] As mentioned herein, each LED chip 130 of the plurality of LED chips 130 comprises a phosphor layer 150 configured to at least partially convert the emitted LED light. According to one example, the phosphor layer 150 covers the plurality of LED chips 130. It should be noted that the phosphor layer 150 may be arranged in relation to the plurality of LED chips 130 and / or the carrier 120 in various ways. According to Fig. 2, the phosphor layer 150 covers the plurality of LED chips 130 and at least a portion of the carrier 120, as indicated by the dashed lines. Nonetheless, according to an example, the phosphor layer 150 only covers each LED chip 130 of the plurality of LED chips 130.

[0052] According to Fig. 2, the phosphor layer 150 is arranged on a first major surface of the carrier 120, covering the plurality of LED chips 130 and at least a portion of the carrier 120. It should be noted that the phosphor layer 150 may (also) be arranged on a second major surface (not shown) of the carrier 120, opposite the first major surface of the carrier 120. This may be preferably if for example the LED lighting device 100 comprises at least one LED chip 130 mounted on the second major surface of the carrier 120, and / or if at least a portion of the carrier 120 is light transmissive, such as translucent or transparent. Furthermore, the LED lighting device 100 of Fig. 2 further comprises an encapsulant 300 covering at least a portion of the carrier 120 and covering at least a portion of the plurality of LED chips 130, wherein the encapsulant 300 comprises the phosphor layer 150. Thus, the encapsulant 300 may cover all, or only a portion, of the carrier 120 and / or of the plurality of LED chips 130. The various phosphor materials 190, 200, 210, 220 of the mixture of the phosphor layer 150 may be uniformly distributed, dispersed, dispensed, or the like throughout the encapsulant 300, or non-uniformly. According to examples, the phosphor materials 190, 200, 210, 220 are arranged in a mosaic pattern, a grid pattern, or a mesh pattern in regard to the plurality of LED chips 130 and / or the carrier 120. According to another example, the phosphor materials 190, 200, 210, 220 are mixed, blended, or the like, together. According to yet another example, the phosphor layer 150 constitutes a coating.

[0053] Although not interpretable from Fig. 2, a distribution ratio of the first type of LED chips 160, the second type of LED chips 170, and the third type of LED chips 180 is 6- 8 : 8-10 : 7-9. More preferably, a distribution ratio of the first type of LED chips 160, the second type of LED chips 170, and the third type of LED chips 180 is 7 : 9 : 8.

[0054] Furthermore, according to the LED lighting device 100 of Fig. 2, at least one of the mass percentage of the first phosphor material 190, mpi, being in a range of 70 - 92 %, the mass percentage of the second phosphor material 200, mp2, being in a range of 3 - 15 %, and the mass percentage of the third phosphor material 210, mp3, being in a range of 0.25 - 5 %, and the mass percentage of the fourth phosphor material 220, mp4, being in a range of 0.25 - 5 %, is fulfilled. More preferably, at least one of the mass percentage of the first phosphor material 190, mpi, being in a range of 80 - 90 %, the mass percentage of the second phosphor material 200, mp2, being in a range of 5 - 10 %, the mass percentage of the third phosphor material 210, mp3, being in a range of 0.5 - 2 %, and the mass percentage of the fourth phosphor material 220, mp4, being in a range of 0.5 - 2 %, is fulfilled.

[0055] According to Fig. 2, a distribution of the first type of LED chips 160, the second type of LED chips 170, and the third type of LED chips 180 is uniform. In other words, the first, second, and third type of LED chips 160, 170, 180 are mounted on the carrier 120 in a uniform arrangement. This uniform distribution of the various types of LED chips 160, 170, 180 may ensure that emitted LED light from the plurality of LED chips 130 is evenly mixed and distributed. Hence, the emitted LED light may have a uniform illumination and color consistency across the entire LED light output area.

[0056] The LED light source light 110 of Fig. 2 has a color rendering index, CRI, in a range of 97 - 99. Furthermore, the LED light source light 110 has a color point within 3 standard deviation of color matching, SDCM, from the black body locus, BBL. According to an example, the LED light source light 110 has a color point <1 SDCM from the BBL.

[0057] Fig. 2 also shows that the LED lighting device 100 further comprises a controller 400 configured to control the luminous flux of the LED light source light 110. The controller 400 is coupled to, and configured to individually control, each type of LED chip 130 of the at least one first type LED chip 160, the at least one second type LED chip 170, and the at least one third type LED chip 180. The controller 400 is coupled (connected) to the first, second, and third type of LED chips 160, 170, 180 wirelessly or by wire. The controller 400 may be configured to individually control the first, second, and third type of LED chips 160, 170, 180 based on a gradual change in for example intensity, beam direction, and / or beam distribution of the respective emitted LED light. The controller 400 may individually control the first, second, and third type of LED chips 160, 170, 180 simultaneously, or successively. According to an example, the controller 400 may be further configured to receive control instructions from a user interface, UI (not shown). The (remote) UI may be configured to receive input from a user. In other words, the controller 400 may be controlled by the UI.

[0058] Fig. 3 schematically shows a LED lamp 500 comprising a LED lighting device 100 according to an exemplifying embodiment of the present invention. It should be noted that the LED lighting device 100 shown in Fig. 3 has several features in common with the LED lighting device 100 shown in Figs. 1 and 2, and it is hereby referred to Figs. 1 and 2, and the associated text, for an increased understanding of some of the features and / or functions of the LED lighting device 100.

[0059] The LED lamp 500, which may constitute substantially any kind of lamp or luminaire, comprises the LED lighting device 100 according to any one of the previously described embodiments. It should be noted that the LED lamp 500 of Fig. 3 comprises (exactly) one LED lighting device 100, but the number of LED lighting devices 100 is in fact arbitrary.

[0060] The LED lamp 500 further comprises a light-transmissive envelope 510, which is exemplified as being bulb-shaped. The light-transmissive envelope 510 at least partially encloses the LED lighting device 100. Hence, the envelope 510 may enclose the LED lighting device 100 fully, or only partially. The LED lamp 500 further comprises a connector 520 for electrically and mechanically connecting the LED lamp 500 to a socket of a luminaire. As shown in Fig. 3, an (optional) controller 400 is provided external of the LED lamp 500. The controller 400 may be configured to control the luminous flux of the LED light source light 110 provided by the LED lighting device 110.

[0061] It should be noted that the lamp 500 comprises (only) one LED lighting device 100, which in turn comprises (only) one first type LED chip 160, (only) one second type LED chip 170, and (only) one third type LED chip 180. Of course, any number of first, second, and third type LED chips 160, 170, 180 is feasible, as well as any number of LED lighting devices 100. Additionally, the LED lighting device 100 may be arranged in a straight configuration as shown in Fig. 3, or in a non-straight configuration such as for example a curved configuration, a 2D / 3D spiral, or a helix.

[0062] Figs. 4-8 show diagrams illustrating emission intensity against corresponding wavelength for reference values, a prior art solution, and LED lighting device 100 according to exemplifying embodiments of the present invention.

[0063] The diagram of Fig. 4 discloses a comparison between three different curves. The curve with a dashed line represents a reference curve, corresponding to the ideal blackbody radiation spectrum. The curve with a dash-dot line corresponds to a prior art solution, referred to as CRI90. The prior art solution according to curve CRI90 utilizes one (1) single LED chip. Furthermore, the curve with a solid line corresponds to a LED lighting device 100 according to an exemplifying embodiment of the present invention. The emitted light associated with curve CRI90 has a CRI of 90, whereas the emitted light associated with CRI99 has a CRI of 99. For the prior art solution associated with curve CRI90, 3 types of fluorescent materials (powders) are used. For the LED lighting device 100 associated with curve CRI99, 4 types of fluorescent materials (powders) are used. It is visible from Fig. 4 that the intensity of the emitted light associated with the curve CRI90 is depressed in the bluegreen region of the wavelength spectrum, wherein said blue-green region may approximately be within a range of 450 - 550 nm. On the contrary, the fitting degree between the curve CRI99 and the ideal blackbody radiation spectrum is improved in the blue-green region.

[0064] The diagrams of Figs. 5-8 each disclose two different curves. The curve with a dashed line once again represents the reference curve, corresponding to the blackbody radiation curve. The curves with a solid line represent exemplifying embodiments of the present invention, and is referred to as fluorescent Ratio 1-4, respectively. Fluorescent Ratio 1-4 represent different mass percentages of the first phosphor material 190, the second phosphor material 200, the third phosphor material 210, and the fourth phosphor material 220, see Table 1.

[0065] Table 1

[0066] Hence, Table 1 discloses different ratio sets 1-4, of mass percentages of the various phosphor materials 190, 200, 210, 220, corresponding to the diagrams of Figs. 5-8, according to exemplifying embodiments. For each exemplifying ratio set 1-4, a corresponding GFC percentage and Ra value is also presented. GFC stands for “Goodness- of-fit Coefficient” and quantifies how well the test spectrum matches the target spectrum, wherein a value of 100% represents a perfect match, and 0% represents no match. For Table 1, the target spectrum is the ideal blackbody radiation spectrum. The Ra value refers to the average color rendering performance for the various ratio sets, wherein a value of 100 represents a high performance, and 0 represents a poor performance. GFC is calculated according to wherein SLED represents the test spectrum and Siarget represents the target spectrum.

[0067] It is visible from Fig. 5-8 that the exemplifying embodiments provide for an improved fitting degree between spectral characteristics of the light emitted by the LED lighting device 100 and the ideal blackbody radiation spectrum. It should be noted that the fitting degree between the spectral characteristics of the blue light emitted by the LED lighting device 100 and the blue light portion of the ideal blackbody radiation spectrum is especially improved. 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. For example, the LED lighting device 100, one or more of the plurality of LED chips 130, the carrier 120, the phosphor layer 150, etc., may have different shapes, dimensions and / or sizes than those depicted / described.

Claims

CLAIMS:

1. A light emitting diode, LED, lighting device (100) configured to provide, during operation, LED light source light (110), the LED lighting device comprising: a carrier (120); a plurality of LED chips (130) mounted on the carrier, wherein each LED chip of the plurality of LED chips comprises at least one LED (140) configured to emit LED light, and a phosphor layer (150) configured to at least partially convert the emitted LED light, wherein the plurality of LED chips comprises at least one first type LED chip (160) configured to emit light with a peak emission wavelength, ta, in a first blue wavelength range, IB, of 430 - 450 nm, at least one second type LED chip (170) configured to emit light with a peak emission wavelength, ta, in a second blue wavelength range, tas, of 445 - 465 nm, and at least one third type LED chip (180) configured to emit light with a peak emission wavelength, ta, in a third blue wavelength range, tas, of 465 - 480 nm, and wherein the phosphor layer comprises a mixture of a first phosphor material (190) configured to emit converted light with a peak emission wavelength, kip, in a first wavelength range, tac, of 535 - 545 nm, a second phosphor material (200) configured to emit converted light with a peak emission wavelength, p, in a second wavelength range, tac, of 600 - 615 nm, a third phosphor material (210) configured to emit converted light with a peak emission wavelength, tap, in a third wavelength range, tac, of 640 - 655 nm, and a fourth phosphor material (220) configured to emit converted light with a peak emission wavelength, tap, in a first wavelength range, tac, of 650 - 680 nm.

2. The LED lighting device according to claim 1, wherein the phosphor layer covers the plurality of LED chips.

3. The LED lighting device according to claim 1 or 2, wherein the phosphor layer only covers each LED chip of the plurality of LED chips.

4. The LED lighting device according to claim 1 or 2, wherein the phosphor layer covers the plurality of LED chips and at least a portion of the carrier.

5. The LED lighting device according to any one of the preceding claims, wherein the phosphor layer constitutes a coating.

6. The LED lighting device according to any one of the preceding claims, further comprising an encapsulant (300) covering at least a portion of the carrier and covering at least a portion of the plurality of LED chips, wherein the encapsulant comprises the phosphor layer.

7. The LED lighting device according to any one of the preceding claims, wherein a distribution ratio of the first type of LED chips, the second type of LED chips, and the third type of LED chips is 6-8 : 8-10 : 7-9.

8. The LED lighting device according to any one of the preceding claims, wherein a distribution of the first type of LED chips, the second type of LED chips, and the third type of LED chips is uniform.

9. The LED lighting device according to any one of the preceding claims, wherein at least one of the mass percentage of the first phosphor material, mpi, is in a range of 70 - 92 %, the mass percentage of the second phosphor material, mp2, is in a range of 3 -15 %, the mass percentage of the third phosphor material, mp3, is in a range of 0.25 -5 %, and the mass percentage of the fourth phosphor material, mp4, is in a range of 0.25 - 5 %, is fulfilled.

10. The LED lighting device according to claim 9, wherein at least one ofthe mass percentage of the first phosphor material, mpi, is in a range of 80 -90 %, the mass percentage of the second phosphor material, mp2, is in a range of 5 -10 %, the mass percentage of the third phosphor material, mp3, is in a range of 0.5 -2 %, and the mass percentage of the fourth phosphor material, mp4, is in a range of 0.5 - 2 %, is fulfilled.

11. The LED lighting device according to any one of the preceding claims, wherein the LED light source light has a color rendering index, CRI, in a range of 97 - 99.

12. The LED lighting device according to any one of the preceding claims, wherein the LED light source light has a color point within 3 standard deviation of color matching, SDCM, from the black body locus, BBL.

13. The LED lighting device according to any one of the preceding claims, further comprising a controller (400) configured to control the luminous flux of the LED light source light.

14. The LED lighting device according to claim 13, wherein the controller is coupled to, and configured to individually control, each type of LED chip of the at least one first type LED chip, the at least one second type LED chip, and the at least one third type LED chip.

15. A LED lamp (500), comprising the LED lighting device according to any one of the preceding claims, a light-transmissive envelope (510) at least partly enclosing the LED lighting device, and a connector (520) for electrically and mechanically connecting the LED lamp to a socket of a luminaire.

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