A light generating system

Abstract

A light generating system (1) configured to, in operation, emit system light (2) and comprising: a first solid state light source (3) configured to, in operation, emit first light source light (4) having a first peak emission wavelength, λ1, in a wavelength range of 420 nm to 490 nm, a second solid state light source (15) configured to, in operation, emit second light source light (16) having a second peak emission wavelength, λ2, in a wavelength range of 600 to 700 nm, or in a wavelength range of 500 nm to 590 nm, a luminescent element (5) comprising a first major surface (51) and a second major surface (52) opposite to the first major surface; and an optical arrangement (20) arranged in front of and remote of the luminescent element (5), the optical arrangement (20) being configured to: (i) receive the first light source light (4) from a first direction, (ii) receive the second light source light (16) from a second direction, (iii) combine the first light source light (4) and the second light source light (16) to form combined light (21), and (iv) redirect the combined light such that the combined light (21) impinges on the luminescent element (5) perpendicular to the first major surface (51) of the luminescent element (5), wherein the optical arrangement (20) comprises a first specular reflecting element (7) configured to reflect the first light source light (4) and a second optical element (17) configured to reflect the second light source light (16).

Description

[0001] 2024PF80401

[0002] 1

[0003] A LIGHT GENERATING SYSTEM

[0004] FIELD OF THE INVENTION

[0005] The invention relates to a light generating system configured to, in operation, emit system light. The invention further relates to a lamp or a luminaire comprising such a light generating system.

[0006] As used herein, the term “violet light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 380 nm to 420 nm.

[0007] 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.

[0008] As used herein, the term “green-yellow light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 500 nm to 590 nm.

[0009] 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.

[0010] As used herein, the term “yellow light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 550 nm to 590 nm.

[0011] As used herein, the term “yellow-orange light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 550 nm to 600 nm.

[0012] As used herein, the term “red light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 600 nm to 680 nm.

[0013] As used herein, the term “white light” is intended to refer to light with correlated color temperature falling within the color temperature range of 2000 K to 9000 K, preferably in a correlated color temperature range of 2700 K to 6500 K.

[0014] As used herein, the term “cool white light” is intended to refer to light with correlated color temperature falling within the color temperature range of 3500 K to 6500 K.

[0015] As used herein, the term “extreme cool white light” is intended to refer to light with correlated color temperature falling within the color temperature range of 6500 K to 9000 K.

[0016] As used herein, the term “warm white light” is intended to refer to light with correlated color temperature falling within the color temperature range of 2000 K to 3500 K.2024PF80401

[0017] 2

[0018] As used herein, the terms “upstream” and “downstream” are intended to be understood relative to the direction of propagation of light through the light generating system. In other words, when a first component or feature is arranged “downstream” of a second component or feature, it may be understood that the first component or feature is arranged in a light receiving relationship with the second component or feature.

[0019] 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.

[0020] As used herein, the term “major part of X” is intended to denote at least 60 %, at least 80 % or at least 90 % of X, where X for instance may be a type of light propagating in or generated by the light generating system.

[0021] BACKGROUND OF THE INVENTION

[0022] Laser-phosphor technology is used in high-end lighting applications such as automotive headlights, projection, and stage-lighting. Recent advancements have simplified and miniaturized the technology such that it can also be used in other lighting applications such as spotlights and flashlights. However, current simplified and miniaturized architectures are not meeting the light quality requirements of general lighting set by major lighting companies.

[0023] US2011 / 279782A1 discloses a light source system comprising a light guide module, a light emitting module and a wavelength conversion element. The light guide module has a first side and a second side. The light emitting module is configured to generate a first light, a second light, a third light and a fourth light. The wavelength conversion element, disposed beside the second side of the light guide module, is configured to receive the second light and the fourth light, and to generate a fifth light according to the second light and the fourth light. The second light and the fourth light are guided to the wavelength conversion element via the light guide module. The first light, the third light and the fifth light are guided to the first side via the light guide module.

[0024] EP3621301A1 discloses an illumination device using a wavelength converting element that is physically separated from a light emitting diode. The wavelength converting element is optically separated from the light source, so that the converted light emitted by the wavelength converting element is prevented from being incident on the light source.

[0025] Accordingly, the temperature limitations of the wavelength converting element are removed, thereby permitting the light source to be driven with an increased current to produce a higher2024PF80401

[0026] 3

[0027] radiance. Moreover, by optically separating the wavelength converting element from the light source, the conversion and recycling efficiency of the device is improved, which also increases radiance.

[0028] CN102252169A discloses a light-emitting device wherein first excitation light and second excitation light are directed to both sides of a light wavelength conversion material having a layered distribution of light wavelength conversion material, respectively. The first excitation light is the excitation light emitted by a solid-state light-emitting chip. A spectroscopic filter device guides the incident light to the wavelength conversion material. The converted light is guided by the first spectroscopic filter device and separated from the light path of the second excitation light into outgoing light. Both sides of the light conversion material of the present invention are excited at the same time. High brightness, high power light output is obtained.

[0029] It is therefore desired to improve the light quality of the simplified and miniaturized architectures of light generating systems configured to, in operation, emit system light. It is further desired to provide a light generating system with improved optical performance, such as improvement in one or more of color over angle, spatial light distribution, and optimized flood-spot light ratio.

[0030] SUMMARY OF THE INVENTION

[0031] It is an object of the present invention to overcome this problem, and to provide a light generation system with a simplified and miniaturized architecture, which light generating system, in operation, emits system light with an improved light quality.

[0032] It is further desired to provide such a light generating system with an improved optical performance, such as improvement in one or more of color over angle, spatial light distribution, and optimized flood-spot light ratio.

[0033] According to a first aspect of the invention, this and other objects are achieved by means of a light generating system configured to, in operation, emit system light, the light generating system comprising: a first solid state light source configured to, in operation, emit first light source light having a first peak emission wavelength, I, in a wavelength range of 420 nm to 490 nm, the first solid state light source comprising one or more of a laser diode, a super-luminescent diode, and a stacked multi -junction light-emitting diode; a second solid state light source configured to, in operation, emit second light source light having a second peak emission wavelength, X2, in a wavelength range of 600 to 690 nm, or in a wavelength range of 500 nm to 590 nm or in a wavelength range of 600 nm to 680 nm, the second solid2024PF80401

[0034] 4

[0035] state light source comprising one or more of a laser diode, a super-luminescent diode, and a stacked multi -junction light-emitting diode; a luminescent element comprising a first major surface and a second major surface opposite to the first major surface; and an optical arrangement arranged in front of and remote of the luminescent element, the optical arrangement being configured to: (i) receive the first light source light from a first direction, (ii) receive the second light source light from a second direction, (iii) combine the first light source light and the second light source light to form combined light, and (iv) redirect the combined light such that the combined light impinges on the luminescent element perpendicular to the first major surface of the luminescent element, wherein the luminescent element is arranged downstream of the optical arrangement, the luminescent element being configured to convert part of the combined light into converted light, the converted light comprising a third peak emission wavelength, 3, being in the range of 500 nm to 590 nm, and wherein the luminescent element further is configured to reflect part of the combined light as reflected combined light; wherein the optical arrangement comprises a first specular reflecting element configured to reflect the first light source light and a second optical element configured to reflect the second light source light, wherein one of the following applies: (i) the second optical element is arranged upstream of the first specular reflecting element, the second optical element is arranged to direct the second light source light to the first specular reflecting element, and the first specular reflecting element is transparent for the second light source light and configured to combine the first light source light and the second light source light as the combined light and to direct the combined light to the luminescent element, (ii) the first specular reflecting element is arranged upstream of the second optical element, the first specular reflecting element is arranged to direct the first light source light to the second optical element, and the second optical element is transparent for the first light source light and configured to combine the first light source light and the second light source light as the combined light and to direct the combined light to the luminescent element, wherein the light generating system further comprises a first collimator arranged downstream of the luminescent element and configured to collimate the reflected combined light and the converted light, and wherein the system light comprises, in an operational mode, a combination of the reflected combined light and the converted light, the system light is white light having a correlated color temperature in a range from 2000K to 9000K and a color rendering index of at least 65.2024PF80401

[0036] 5

[0037] Thereby, a light generation system with a simplified and miniaturized architecture, which light generating system, in operation, emits system light with an improved light quality is provided for.

[0038] Such a light generating system furthermore has an improved optical performance, such as improvement in one or more of color over angle, spatial light distribution, and optimized flood-spot light ratio.

[0039] The first specular reflecting element of the optical arrangement may have a reflectivity of at least 80%, or at least 90%, such as at least 95%, for the first light source light.

[0040] The second reflecting element of the optical arrangement may have a reflectivity of at least 80%, or at least 90%, such as at least 95%, for the second light source light.

[0041] The first specular reflecting element of the optical arrangement may have a transmissivity of at least 80%, or at least 90%, such as at least 95%, for the second light source light.

[0042] The second reflecting element of the optical arrangement may have a transmissivity of at least 80%, or at least 90%, such as at least 95%, for the first light source light.

[0043] The first collimator may comprise or be one or more lenses.

[0044] The system light may be white light having a correlated color temperature in a range from 2500 K to 6500 K, or from 2700 K to 4500 K.

[0045] The system light may be white light having a color rendering index of at least 70, at least 75, at least 80, or at least 85.

[0046] The light generating system may further comprise a third solid state light source configured to, in operation, emit third light source light having a fourth peak emission wavelength, 4, the third solid state light source comprising one or more of a laser diode, a super-luminescent diode, and a stacked multi -junction light-emitting diode; wherein, if the second peak emission wavelength, 2, is in the wavelength range of 600 to 700 nm, the fourth peak emission wavelength, X4, is in the wavelength range of 500 nm to 590 nm, or if the second peak emission wavelength, 2, is in the wavelength range of 500 nm to 590 nm, the fourth peak emission wavelength, X4, is in the wavelength range of 600 to 700 nm, wherein the optical arrangement further is configured to: (v) receive the third light source light from a third direction, and (vi) combine the first light source light, the second light source light, and the third light source light to form the combined light, wherein the optical2024PF80401

[0047] 6

[0048] arrangement further comprises a third optical element configured to reflect the third light source light, wherein one of the following applies:

[0049] (i) the third optical element is arranged upstream of the first specular reflecting element and upstream of the second optical element, the third optical element is arranged to direct the third light source light to the second optical element, the first specular reflecting element and the second optical element are transparent for the third light source light, and the first specular reflecting element is configured to combine the first light source light, the second light source light, and the third light source light as the combined light and to direct the combined light to the luminescent element,

[0050] (ii) the third optical element is arranged upstream of the first specular reflecting element and upstream of the second optical element, the third optical element is arranged to direct the third light source light to the first specular reflecting element, the first specular reflecting element and the second optical element are transparent for the third light source light, and the second optical element is configured to combine the first light source light, the second light source light, and the third light source light as the combined light and to direct the combined light to the luminescent element,

[0051] (iii) the third optical element is arranged between the first specular reflecting element and the second optical element, the third optical element is arranged to direct the third light source light to the first specular reflecting element, the first specular reflecting element is transparent for the third light source light, the third optical element is transparent for the second light source light, and the first specular reflecting element is configured to combine the first light source light, the second light source light, and the third light source light as the combined light and to direct the combined light to the luminescent element, (iv) the third optical element is arranged between the first specular reflecting element and the second optical element, the third optical element is arranged to direct the third light source light to the second optical element, the second optical element is transparent for the third light source light, the third optical element is transparent for the first light source light, and the second optical element is configured to combine the first light source light, the second light source light, and the third light source light as the combined light and to direct the combined light to the luminescent element,

[0052] (v) the third optical element is arranged downstream of the first specular reflecting element and downstream of the second optical element, the first specular reflecting element is arranged to direct the first light source light and the second light source light to the third optical element, the third optical element is transparent for the first light source light and2024PF80401

[0053] 7

[0054] transparent for the second light source light, and the third optical element is configured to combine the first light source light, the second light source light, and the third light source light as the combined light and to direct the combined light to the luminescent element, (vi) the third optical element is arranged downstream of the first specular reflecting element and downstream of the second optical element, the second reflecting element is arranged to direct the second light source light and the first light source light to the third optical element, the third optical element is transparent for the first light source light and is transparent for the second light source light, and the third optical element is configured to combine the first light source light, the second light source light, and the third light source light as the combined light and to direct the combined light to the luminescent element, and wherein

[0055] the system light comprises, in an operational mode, a combination of the reflected combined light and the converted light.

[0056] Thereby, a light generation system with a simplified and miniaturized architecture, which light generating system, in operation, emits system light with a further improved light quality, and especially an increased intensity, is provided for.

[0057] The first specular reflecting element, the second optical element, and, where provided, the third optical element may be specularly reflecting mirrors obliquely arranged with respect the first major surface of the luminescent element.

[0058] The two or three obliquely arranged specular reflecting elements may be arranged (i) vertically stacked and mutually spaced apart, or (ii) crossed, or (iii) mutually spaced apart and forming the respective legs of a V-shape.

[0059] Thereby, a particularly compact optical arrangement, and thus light emitting device, is provided for.

[0060] The first specular reflecting element may be a reflective polarizer, wherein the reflective polarizer is (i) reflective for the first light source light, and transmissive for zero, one or both of the second light source light and the third light source light, or (ii) transmissive for the first light source light and reflective for zero, one or both of the second light source light and the third light source light.

[0061] At least one of the specular reflecting elements may be a dichroic mirror, wherein the dichroic mirror is (i) reflective for the first light source light, and transmissive for zero, one or both of the second light source light and the third light source light, or (ii) transmissive for the first light source light and reflective for zero, one or both of the second light source light and the third light source light.2024PF80401

[0062] 8

[0063] Thereby a particularly simple light emitting device with a high optical efficiency is provided for.

[0064] The second optical element may be a reflective polarizer, wherein the reflective polarizer is (i) reflective for the second light source light and transmissive for zero, one or both of the first light source light and the third light source light, or (ii) transmissive for the second light source light and reflective for zero, one or both of the first light source light and the third light source light.

[0065] The second optical element may be a dichroic mirror, wherein the dichroic mirror is (i) reflective for the second light source light and transmissive for zero, one or both of the first light source light and the third light source light, or (ii) transmissive for the second light source light and reflective for zero, one or both of the first light source light and the third light source light.

[0066] Thereby a particularly simple light emitting device with a high optical efficiency is provided for.

[0067] The third optical element may be a reflective polarizer, wherein the reflective polarizer is (i) reflective for the third light source light, and transmissive for zero, one or both of the first light source light and the second light source light, or (ii) transmissive for the third light source light and reflective for zero, one or both of the first light source light and the second light source light.

[0068] The third optical element may be a dichroic mirror, wherein the dichroic mirror is (i) reflective for the third light source light and transmissive for zero, one or both of the first light source light and the second light source light, or (ii) transmissive for the third light source light and reflective for zero, one or both of the first light source light and the second light source light.

[0069] Thereby a particularly simple light emitting device with a high optical efficiency is provided for.

[0070] The luminescent element may further be configured to diffuse the reflected combined light.

[0071] A major part of the converted light and a major part of the reflected combined light may not be impinging onto the optical arrangement.

[0072] For instance, more than 85 %, more than 90 %, or more than 95 %, of the converted light and more than 85 %, more than 90 %, or more than 95 %, of the reflected combined light may not be impinging onto the optical arrangement.2024PF80401

[0073] 9

[0074] Thereby, loss of converted light and reflected combined light, which may otherwise occur at the optical arrangement, is minimized, or avoided.

[0075] The first major surface has a surface area, Al, and wherein the first specular reflecting element has a largest surface area, A2, wherein A2 < 0.8*Al, preferably A2 < O.6*A1, more preferably A2 < 0.5*Al, most preferably A2 < O.2*A1. The largest surface area, A2, is the area where part of the first converted light is impinging on the first specular reflecting element.

[0076] The obtained effect is improved efficiency and / or homogeneity of the system light. The reason is that the major part of the converted light is not imping on the first specular reflecting element.

[0077] In an embodiment, a first fraction of the first converted light, Fl, is impinging on the first specular reflecting element and a second fraction of the first converted light, F2, is bypassing the first specular reflecting element, and wherein F2 > 1.2*F1, preferably F2 > 1.5*F1, more preferably F2 > 1.8*F1, even more preferably F2 > 2*F1, even more preferably F2 > 3 *F 1 , most preferably F2 > 5 *F 1.

[0078] The light generating system may further comprise a first further optical element arranged downstream of the first solid state light source and configured to collimate the first light source light.

[0079] Thereby, loss of first light source light before the first light source light reaches the first specular reflecting element may be minimized or avoided altogether.

[0080] The light generating system may further comprise a second further optical element arranged downstream of the second solid state light source and configured to collimate the second light source light.

[0081] Thereby, loss of second light source light before the second light source light reaches the second reflecting element may be minimized or avoided altogether.

[0082] When a third solid state light source is provided, the light generating system may further comprise a third further optical element arranged downstream of the third solid state light source and configured to collimate the third light source light.

[0083] Thereby, loss of third light source light before the second light source light reaches the third reflecting element may be minimized or avoided altogether.

[0084] The light generating system may further comprise a controller configured to individually control the first solid state light source, the second solid state light source, and, where provided, the third solid state light source.2024PF80401

[0085] 10

[0086] The light generating system may further comprise a sensor configured to sense an operational parameter of the light generating system and to provide the sensed operational parameter to the controller for controlling the first solid state light source, the second solid state light source, and, where provided, the third solid state light source.

[0087] Thereby, it becomes possible to adapt the obtained device light to various different applications and to the light requirements thereof. For instance, it becomes possible to control the light generating system to emit either spotlight, for instance for visualizing objects, or flood light, for instance for orientation. It also becomes possible to control the flood-spot light ratio. Furthermore, it becomes possible to control the correlated color temperature, CCT, and the color rendering index, CRI of the device light.

[0088] The light generating system may further comprise a heat sink element, wherein the luminescent element is arranged with the second major surface in thermal contact with the heat sink element, wherein one or more of the following applies: (i) an element or layer being reflective to visible light and transmissive to heat is arranged between the luminescent element and the heat sink element, and (ii) the heat sink element comprises a reflective material.

[0089] Thereby, efficient and sufficient cooling of the luminescent element is provided for. Also, light losses, which may otherwise occur in the heat sink element, are avoided thanks to the light reflecting layer or element. This in turn further improves the quality of the device light emitted by the light generating system.

[0090] The first light source light may be blue light. The second light source light may be red light or green light. The converted light may be green-yellow light, yellow light, yellow-orange light, or any combination thereof.

[0091] At least one of the first solid state light source, the second solid state light source, and, where provided, the third solid state light source comprises a semiconductor laser diode arranged in a casing comprising a light exit window.

[0092] Thereby, particularly compact solid state light sources are provided for.

[0093] The light generating system may further comprise a heat sink arranged in thermal contact with the semiconductor laser diode.

[0094] The light generating system may further comprise a bonding wire arranged in physical contact with the semiconductor laser diode or with a metallic strip provided on the semiconductor laser diode.

[0095] The light generating system may further comprise at least one connector pin arranged in electrical contact with the semiconductor laser diode.2024PF80401

[0096] 11

[0097] The light generating system may further comprise a photodiode, the photodiode being configured to monitor the semiconductor laser diode.

[0098] The light generating system may further comprise a base, the semiconductor laser diode being arranged on the base.

[0099] The invention further relates to a lamp or a luminaire comprising a light generating system according to the invention.

[0100] The lamp or the luminaire may, thanks to the light generating system, provide system light with an improved brightness and / or an improved color quality.

[0101] The lamp or luminaire may be any type of lamp and luminaire, but particularly an automotive headlight, a projection luminaire, a stage lighting luminaire or fixture and a flashlight.

[0102] It is noted that the invention relates to all possible combinations of features recited in the claims.

[0103] BRIEF DESCRIPTION OF THE DRAWINGS

[0104] 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.

[0105] Fig. 1 schematically shows a light generating system according to the invention and comprising an optical device, as well as a first and a second solid state light source and a luminescent element.

[0106] Fig. 2 schematically shows another light generating system according to the invention and comprising an optical device, as well as a first and a second solid state light source and a luminescent element.

[0107] Fig. 3 schematically shows a light generating system according to the invention and comprising another optical device, as well as a first and a second solid state light source and a luminescent element.

[0108] Fig. 4 schematically shows another light generating system according to the invention and comprising another optical device, as well as a first, a second and a third solid state light source and a luminescent element.

[0109] Fig. 5 schematically shows a perspective view of a solid state light source of a light generating system according to the invention.

[0110] Fig. 6 schematically shows a close up of the section V of the solid state light source according to Fig. 5.2024PF80401

[0111] 12

[0112] Fig. 7 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 YAG phosphor.

[0113] Fig. 8 shows a schematical side view of a lamp comprising a light generating system according to the invention.

[0114] Fig. 9 shows a schematical side view of a luminaire comprising a lamp and a light generating system according to the invention.

[0115] 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.

[0116] DETAILED DESCRIPTION

[0117] 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, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0118] Fig. 1 schematically shows a light generating system 1 according to the invention. Irrespective of the embodiment, the light generating system 1 comprises a first solid state light source 3, a second solid state light source 15, a luminescent element 5 and an optical device 20. The light generating system 1 is configured to, in operation, emit system light 2.

[0119] The first solid state light source 3 is configured to, in operation, emit first light source light 4 comprising a first peak emission wavelength, I, being in the wavelength range of 420 nm to 490 nm. The first light source light 4 is blue light. The first solid state light source 3 comprises one or more of a laser diode, a super-luminescent diode, and a stacked multi -junction light-emitting diode.

[0120] The second solid state light source 15 is configured to, in operation, emit second light source light 16. The second light source light 16 comprises a third peak emission wavelength, X3, being in the range of 420 nm to 490 nm. Alternatively, the second light source light 16 comprises a third peak emission wavelength, X3, being in the wavelength range of 600 nm to 690 nm, or 600 nm to 700 nm, or 600 nm to 680 nm. The second light2024PF80401

[0121] 13

[0122] source light 16 may thus be blue light or red light. In case the second light source light 16 is blue light, the first peak emission wavelength, XI, and the third peak emission wavelength, X3, may be the same or may be different from one another. For instance, the first peak emission wavelength, I, and the third peak emission wavelength, X3, may be chosen such that I X3- XI I > 20 nm, or such that I X3- XI I > 30 nm. The second solid state light source 15 comprises one or more of a laser diode, a super-luminescent diode, and a stacked multijunction light-emitting diode.

[0123] The luminescent element 5 comprises a first major surface 51 and a second major surface 52 opposite to the first major surface 51. The luminescent element 5 is arranged downstream of the first solid state light source 3 and downstream of the second light source 15.

[0124] The optical device 20 is arranged in front of the luminescent element 5. The optical device 20 is arranged remote of the luminescent element 5. The optical device 20 is configured to receive the first light source light 4 from a first direction. The optical device 20 is further configured to receive the second light source light 16 from a second direction. The optical device 20 is further configured to combine the first light source light 4 and the second light source light 16 to form combined light 21. The optical device 20 is further configured to redirect the combined light 21 such that the combined light 21 impinges on the luminescent element 5 perpendicular to the first major surface 51. The optical device 20 may for instance be configured to redirect the combined light 21 such that the combined light 21 impinges in an angle of 90 degrees, in an angle of 90 degrees + / -5 degrees, or in an angle of 90 degrees + / -2 degrees, with the first major surface 51.

[0125] The luminescent element 5 is further arranged downstream of the optical device 20. The luminescent element 5 is configured to convert at least a part of the combined light 21 into converted light 6. The converted light 6 comprises a third peak emission wavelength, X3, being in the range of 500 nm to 600 nm. The converted light 6 may be yellow light, green-yellow light, or orange-yellow light. The luminescent element 5 is further configured to reflect a part of the combined light as reflected combined light.

[0126] The optical device 20 is transparent for the converted light 6 and for any reflected combined light 42.

[0127] The optical device 20 comprises two obliquely arranged reflecting elements 7 and 17. The two obliquely arranged reflecting elements 7 and 17 are arranged mutually spaced apart. The optical device 20 comprises a first specular reflecting element 7 and a second reflecting element 17. The first specular reflecting element 7 and the second reflecting2024PF80401

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[0129] element 17 are arranged mutually spaced apart. The two obliquely arranged reflecting elements 7 and 17 may be arranged extending perpendicular to one another. Thus, the first specular reflecting element 7 and the second reflecting element 17 may be arranged extending perpendicular to one another. In the embodiment shown in Fig. 1, the first specular reflecting element 7 and the second reflecting element 17 are further arranged mutually spaced apart and forming the respective legs of a V-shape.

[0130] The first specular reflecting element 7 is arranged in front of and remote of the luminescent element 5. The first specular reflecting element 7 is arranged and configured to reflect the first light source light 4 and to direct the first light source light 4 onto the luminescent element 5 such that the first light source light 4 impinges on the luminescent element 5 perpendicular to the first major surface 51 of the luminescent element 5. The first specular reflecting element 7 may for instance be arranged and configured to direct the first light source light 4 onto the luminescent element 5 such that the first light source light 4 impinges on the luminescent element in an angle of 90 degrees + / -5 degrees, or in an angle of 90 degrees + / -2 degrees, to the first major surface 51 of the luminescent element 5. The first specular reflecting element 7 is configured to reflect the first solid state light source light 4 under an angle being between 40 and 50 degrees.

[0131] The first specular reflecting element 7 may be transparent for the converted light 6 and for any reflected combined light 42.

[0132] The first specular reflecting element 7 may be a reflective polarizer. The reflective polarizer is reflective for the first light source light 4 and transmissive for the second light source light 16. Alternatively, the reflective polarizer is transmissive for the first light source light 4 and reflective for the second light source light 16.

[0133] Alternatively, the first specular reflecting element 7 may be a dichroic mirror. The dichroic mirror may be reflective for the first light source light 4 and transmissive for the second light source light 16. Alternatively, the dichroic mirror may be transmissive for the first light source light 4 and reflective for the second light source light 16. The dichroic mirror may comprise or be a narrow-band blue dichroic mirror. The reflection band of the narrow-band blue dichroic mirror is less than 20 nm. The narrow-band blue dichroic mirror may be configured to reflect first solid state light source light 4 incident in an angle being between 40 and 50 degrees, between 43 and 47 degrees, or between 44 and 46 degrees, only.

[0134] The second reflecting element 17 is arranged remote of the luminescent element 5. The second reflecting element 17 is further arranged behind the first specular reflecting element 7. The second reflecting element 17 is configured to reflect the second2024PF80401

[0135] 15

[0136] light source light 16 and to direct the second light source light 16 onto the luminescent element 5 such that the second light source light 16 impinges on the luminescent element 5 perpendicular to the first major surface 51 of the luminescent element 5. The second reflecting element 17 may for instance be arranged and configured to direct the second light source light 16 onto the luminescent element 5 such that the second light source light 16 impinges on the luminescent element in an angle of 90 degrees + / -5 degrees, or in an angle of 90 degrees + / -2 degrees, to the first major surface 51 of the luminescent element 5. The second reflecting element 17 is configured to reflect the second solid state light source light 16 under an angle being between 40 and 50 degrees.

[0137] The second reflecting element 17 may be transparent for the converted light 6 and for any reflected combined light 42.

[0138] The second reflecting element 17 may be a reflective polarizer. The reflective polarizer may be reflective for the second light source light 16. Alternatively, the reflective polarizer may be transmissive for the second light source light 16.

[0139] Alternatively, the second reflecting element 17 may be a dichroic mirror. The dichroic mirror may be reflective for the second light source light 16. Alternatively, the dichroic mirror may be transmissive for the second light source light 16. The dichroic mirror may comprise or be a narrow-band blue dichroic mirror. The reflection band of the narrowband blue dichroic mirror is less than 20 nm. The narrow-band blue dichroic mirror may be configured to reflect second solid state light source light 16 incident in an angle being between 40 and 50 degrees, between 43 and 47 degrees, or between 44 and 46 degrees, only.

[0140] A first collimator 11 is arranged downstream of the luminescent element 5 and downstream of the optical element 20. The first collimator 11 is configured to collimate the reflected combined light 42 and the converted light 6.

[0141] In an operational mode, the system light 2 generated by the light generating system 1 comprises a combination of the reflected combined light 42 and the converted light 6. Therefore, the first collimator 11 is in other words configured to collimate the system light 2.

[0142] The combined light 21 forms a spot on the luminescent element 5. The spot comprises a spot size, a spot shape, and a spot position on the first major surface 51 of the luminescent element 5. The spot may be arranged centered with respect to the first collimator 11.

[0143] The light generating system 1 further comprises an optional controller 28. The controller 28 is configured to individually control the first light source light 4 and the second2024PF80401

[0144] 16

[0145] light source light 16. The controller 28 is further configured to control the intensity of the first light source light 4 and the intensity of the second light source light 16. Alternatively, or additionally, the controller 28 may be configured to control a spot size of the combined light 21 on the luminescent element 5. Alternatively, or additionally, the controller 28 may be configured to control a spot shape of the combined light 21 on the luminescent element 5. Alternatively, or additionally, the controller 28 may be configured to control a spot position of the combined light 21 on the luminescent element 5. Alternatively, or additionally, the controller 28 may be configured to control a color rendering index, CRI and / or a correlated color temperature, CCT, of the system light 2.

[0146] The light generating system 1 further comprises an optional sensor 41. The sensor 41 is configured to sense an operational parameter of the light generating system 1. The sensor 41 is further configured to provide the sensed operational parameter to the controller 28 for controlling the first solid state light source 3, the second solid state light source 15, and, where provided, the third solid state light source 24. Alternatively, or additionally, the controller 28 may be configured to control a spot size of the combined light 21 on the luminescent element 5. The operational parameter may be a spot shape of the combined light 21 on the luminescent element 5. Alternatively, or additionally, the operational parameter may be a spot position of the combined light 21 on the luminescent element 5. Alternatively, or additionally, the operational parameter may be a parameter related to the system light 2, such as a color rendering index, CRI and / or a correlated color temperature, CCT, and / or an intensity of the system light 2.

[0147] The light generating system 1 further comprises an optional third reflecting element 8. The third reflecting element 8 is arranged between the first solid state light source 3 and the first specular reflecting element 7. The third reflecting element 8 is configured to receive and reflect the first light source light 4 and to direct the first light source light 4 onto the first specular reflecting element 7. The third reflecting element 8 is or may be a specular reflecting element.

[0148] The light generating system 1 further comprises an optional fourth reflecting element 19. The fourth reflecting element 19 is arranged between the second solid state light source 15 and the second reflecting element 17. The fourth reflecting element 19 is configured to receive and reflect the second light source light 16 and to direct the second light source light 16 onto the second reflecting element 17. The fourth reflecting element 19 is or may be a specular reflecting element.2024PF80401

[0149] 17

[0150] The light generating system 1 further comprises an optional second optical element 12. The second optical element 12 is arranged downstream of the luminescent element 5. The second optical element 12 may be a transparent or translucent optical element. Alternatively, the second optical element 12 may be a diffusing element configured to diffuse the system light 2.

[0151] The light generating system 1 further comprises an optional heat sink element 9. The luminescent element 5 is arranged with the second major surface 52 facing or in direct contact with the heat sink element 9. The heat sink element 9 cools the luminescent element 5. The heat sink element 9 may further be configured to cool the first solid state light source 3.

[0152] The light generating system 1 further comprises an optional element or layer 10 being reflective to light and transmissive to heat. The element or layer 10 is arranged between the luminescent element 5 and the heat sink element 9.

[0153] The light generating system 1 further comprises an optional first further optical element 22. The first further optical element 22 is arranged downstream of the first solid state light source 3. The first further optical element 22 is configured to collimate the first light source light 4.

[0154] The light generating system 1 further comprises an optional second further optical element 23. The second further optical element 23 is arranged downstream of the second solid state light source 15. The second further optical element 23 is configured to collimate the second light source light 16.

[0155] The light generating system 1 further comprises an optional housing 13. The housing 13 is configured to house the luminescent element 5 and the specular reflecting element 7, as well as, where provided, the reflecting element 8, the first optical element 11, and the second optical element 12. The housing 13 comprises an inner surface 14 facing the luminescent element 5 and the specular reflecting element 7. The inner surface 14 may comprise a light reflective layer or coating.

[0156] Fig. 2 schematically shows another light generating system 100 according to the invention. The light generating system 100 differs from the light generating system 1 according to Fig. 1 and described above in virtue of the following features.

[0157] The luminescent element 5 is further configured to diffuse at least a part of the combined light 21 thereby providing diffuse light 27. The system light 2 thus now comprises a combination of the reflected combined light 42, the converted light 6, and the diffuse light 27.2024PF80401

[0158] 18

[0159] Fig. 3 schematically shows another light generating system 101 according to the invention. The light generating system 101 differs from the light generating system 1 according to Fig. 1 and described above in virtue of the following features.

[0160] The optical device 20 comprises two obliquely arranged reflecting elements 7 and 17. The two obliquely arranged reflecting elements 7 and 17 are arranged in a crossed configuration. The optical device 20 comprises a first specular reflecting element 7 and a second reflecting element 17. The first specular reflecting element 7 and the second reflecting element 17 are arranged in a crossed configuration.

[0161] Alternatively, the two obliquely arranged reflecting elements 7 and 17 may be arranged in a stacked configuration. Thus, the first specular reflecting element 7 and the second reflecting element 17 may be arranged in a stacked configuration.

[0162] In either case, the two obliquely arranged reflecting elements 7 and 17 may be arranged extending perpendicular to one another. Thus, the first specular reflecting element 7 and the second reflecting element 17 may be arranged extending perpendicular to one another.

[0163] Fig. 4 schematically shows another light generating system 102 according to the invention. The light generating system 102 differs from the light generating systems 1, 100 and 101 according to Figs. 1 to 3 and described above in virtue of the following features.

[0164] The light generating system 102 further comprises a third solid state light source 24. The third solid state light source 24 is configured to, in operation, emit third light source light 25. The third light source light 25 comprises a fourth peak emission wavelength, X4. The fourth peak emission wavelength, X4, may be chosen as follows. If the second peak emission wavelength, 2, is in the wavelength range of 600 to 700 nm, the fourth peak emission wavelength, X4, is chosen to be in the wavelength range of 490 nm to 560 nm. Hence, if the second light source light 16 is red light, the third light source light 25 is blue light. If the second peak emission wavelength, 2, is in the wavelength range of 490 nm to 560 nm, the fourth peak emission wavelength, 4, is chosen to be in the wavelength range of 600 to 700 nm. Hence, if the second light source light 16 is blue light, the third light source light 25 is red light.

[0165] The optical device 20 is further configured to receive the third light source light 25 from a third direction. The optical device 20 is further configured to combine the first light source light 4, the second light source light 16, and the third light source light 25 to form the combined light 21. The optical device 20 is further configured to redirect the combined light 21 such that the combined light impinges on the luminescent element 5 in an2024PF80401

[0166] 19

[0167] angle of 90 degrees with the first major surface 51. The optical device 20 is further transparent for the third light source light 25. Alternatively, the optical device 20 is further reflective for the third light source light 25.

[0168] The optical device 20 now comprises three obliquely arranged reflecting elements 7, 17 and 30. As shown in Fig. 4, the three obliquely arranged reflecting elements 7, 17 and 30 are arranged mutually spaced apart. The optical device 20 comprises a first specular reflecting element 7, a second reflecting element 17, and a third reflecting element 30. The first specular reflecting element 7, the second reflecting element 17, and the third reflecting element 30 are arranged mutually spaced apart.

[0169] In alternatives, the three obliquely arranged reflecting elements 7, 17 and 30 may be arranged in a crossed configuration or in a stacked configuration. The first specular reflecting element 7, the second reflecting element 17, and the third reflecting element 30 may be arranged in a crossed configuration or in a stacked configuration.

[0170] The first specular reflecting element 7 may be a reflective polarizer. In the embodiment shown in Fig. 4, the reflective polarizer is reflective for the first light source light 4, transmissive for the second light source light 16, and transmissive for the third light source light 25. Alternatively, the reflective polarizer may be transmissive for the first light source light 4, reflective for the second light source light 16, and reflective for the third light source light 25. The reflective polarizer may further be transparent for first solid state light source light 4 reflected by the luminescent element 5.

[0171] Alternatively, the first specular reflecting element 7 may be a dichroic mirror. In the embodiment shown in Fig. 4, the dichroic mirror is reflective for the first light source light 4, transmissive for the second light source light 16, and transmissive for the third light source light 25. Alternatively, the dichroic mirror may be transmissive for the first light source light 4, reflective for the second light source light 16, and reflective for the third light source light 25. The dichroic mirror may comprise or be a narrow-band blue dichroic mirror. The reflection band of the narrow-band blue dichroic mirror is less than 20 nm. The narrowband blue dichroic mirror may be configured to reflect first solid state light source light 4 incident in an angle being between 40 and 50 degrees, between 43 and 47 degrees, or between 44 and 46 degrees, only.

[0172] The second reflecting element 17 is arranged remote of the luminescent element 5. In the embodiment shown in Fig. 4, the second reflecting element 17 is further arranged between the first specular reflecting element 7 and the third reflecting element 30. The second reflecting element 17 is configured to reflect the second light source light 16 and2024PF80401

[0173] 20

[0174] to direct the second light source light 16 onto the luminescent element 5 such that the second light source light 16 impinges on the luminescent element 5 perpendicular to the first major surface 51 of the luminescent element 5. The second reflecting element 17 may for instance be arranged and configured to direct the second light source light 16 onto the luminescent element 5 such that the second light source light 16 impinges on the luminescent element in an angle of 90 degrees + / -5 degrees, or in an angle of 90 degrees + / -2 degrees, to the first major surface 51 of the luminescent element 5. The second reflecting element 17 is configured to reflect the first second state light source light 16 under an angle being between 40 and 50 degrees.

[0175] The second reflecting element 17 may be transparent for the converted light 6 and for any reflected combined light 42.

[0176] The second reflecting element 17 may be a reflective polarizer. In the embodiment shown in Fig. 4, the reflective polarizer may be reflective for the second light source light 16 and transmissive for the third light source light 25. Alternatively, the reflective polarizer may be transmissive for the second light source light 16 and reflective for the third light source light 25.

[0177] Alternatively, the second reflecting element 17 may be a dichroic mirror. In the embodiment shown in Fig. 4, the dichroic mirror may be reflective for the second light source light 16 and transmissive for the third light source light 25. Alternatively, the dichroic mirror may be transmissive for the second light source light 16 and reflective for the third light source light 25. The dichroic mirror may comprise or be a narrow-band blue dichroic mirror. The reflection band of the narrow-band blue dichroic mirror is less than 20 nm. The narrow-band blue dichroic mirror may be configured to reflect second solid state light source light 16 incident in an angle being between 40 and 50 degrees, between 43 and 47 degrees, or between 44 and 46 degrees, only.

[0178] The third reflecting element 30 is arranged remote of the luminescent element 5. In the embodiment shown in Fig. 4, the third reflecting element 30 is further arranged upstream of the first specular reflecting element 7 and upstream of the second specular reflective element 17. The third reflecting element 30 is configured to reflect the third light source light 25 and to direct the third light source light 25 onto the luminescent element 5 such that the third light source light 25 impinges on the luminescent element 5 perpendicular to the first major surface 51 of the luminescent element 5. The third reflecting element 30 may for instance be arranged and configured to direct the third light source light 25 onto the luminescent element 5 such that the third light source light 25 impinges on the luminescent2024PF80401

[0179] 21

[0180] element in an angle of 90 degrees + / -5 degrees, or in an angle of 90 degrees + / -2 degrees, to the first major surface 51 of the luminescent element 5. The third reflecting element 30 is configured to reflect the third second state light source light 25 under an angle being between 40 and 50 degrees.

[0181] The third reflecting element 30 may be transparent for the converted light 6 and for any reflected combined light 42.

[0182] The third reflecting element 30 may be a reflective polarizer. In the embodiment shown in Fig. 4, the reflective polarizer may be reflective for the third light source light 25. Alternatively, the reflective polarizer may be transmissive for the third light source light 25.

[0183] Alternatively, the third reflecting element 17 may be a dichroic mirror. In the embodiment shown in Fig. 4, the dichroic mirror may be reflective for the third light source light 25. Alternatively, the dichroic mirror may be transmissive for the third light source light 25. The dichroic mirror may comprise or be a narrow-band blue dichroic mirror. The reflection band of the narrow-band blue dichroic mirror is less than 20 nm. The narrow-band blue dichroic mirror may be configured to reflect third solid state light source light 25 incident in an angle being between 40 and 50 degrees, between 43 and 47 degrees, or between 44 and 46 degrees, only.

[0184] In an alternative embodiment, the third optical element 30 is arranged upstream of the first specular reflecting element 7 and upstream of the second optical element 17, and the third optical element 30 is arranged to direct the third light source light 25 to the first specular reflecting element 7. The first specular reflecting element 7 and the second optical element 17 are transparent for the third light source light 25. The second optical element 17 is configured to combine the first light source light 4, the second light source light 16, and the third light source light 25 as the combined light 21 and to direct the combined light 21 to the luminescent element 5.

[0185] In an alternative embodiment, the third optical element 30 is arranged between the first specular reflecting element 7 and the second optical element 17, and the third optical element 30 is arranged to direct the third light source light 25 to the first specular reflecting element 7. The first specular reflecting element 7 is transparent for the third light source light 25. The third optical element 30 is transparent for the second light source light 16. The first specular reflecting element 7 is configured to combine the first light source light 4, the second light source light 16, and the third light source light 25 as the combined light 21 and to direct the combined light 21 to the luminescent element 5.2024PF80401

[0186] 22

[0187] In an alternative embodiment, the third optical element 30 is arranged between the first specular reflecting element 7 and the second optical element 17, and the third optical element 30 is arranged to direct the third light source light 25 to the second optical element 17. The second optical element 17 is transparent for the third light source light 25. The third optical element 30 is transparent for the first light source light 4. The second optical element 17 is configured to combine the first light source light 4, the second light source light 16, and the third light source light 25 as the combined light 21 and to direct the combined light 21 to the luminescent element 5.

[0188] In an alternative embodiment, the third optical element 30 is arranged downstream of the first specular reflecting element 7 and downstream of the second optical element 17. The first specular reflecting element 7 is arranged to direct the first light source light 4 and the second light source light 16 to the third optical element 30. The third optical element 30 is transparent for the first light source light 4 and transparent for the second light source light 16. The third optical element 30 is configured to combine the first light source light 4, the second light source light 16, and the third light source light 25 as the combined light 21 and to direct the combined light 21 to the luminescent element 5.

[0189] In an alternative embodiment, the third optical element 30 is arranged downstream of the first specular reflecting element 7 and downstream of the second optical element 17. The second reflecting element 17 is arranged to direct the second light source light 16 and the first light source light 4 to the third optical element 30. The third optical element 30 is transparent for the first light source light 4 and is transparent for the second light source light 16. The third optical element 30 is configured to combine the first light source light 4, the second light source light 16, and the third light source light 25 as the combined light 21 and to direct the combined light 21 to the luminescent element 5.

[0190] The first collimator 11 is configured to collimate the reflected combined light 42 and the converted light 6.

[0191] The system light 2 now comprises a combination of the reflected combined light 42 and the converted light 6. The first collimator 11 is thus configured to collimate the system light 2.

[0192] The controller 28 is further configured to individually control the first light source light 4, the second light source light 16, and the third light source light 25. The controller 28 is further configured to control the intensity of the first light source light 4, the intensity of the second light source light 16, and the intensity of the third light source light2024PF80401

[0193] 23

[0194] The light generating system 102 further comprises an optional third further optical element 26. The third further optical element 26 is arranged downstream of the third solid state light source 24. The third further optical element 26 is configured to collimate the third light source light 25.

[0195] Turning now to Figs. 5 and 6, further details of an exemplary solid state light source 3, 15, 24 of a light generating system 1, 100, 101, 102 according to the invention will be described. Fig. 5 schematically shows a perspective view of the exemplary solid state light source 3, 15, 24 of a light generating system 1, 100, 101, 102 according to the invention. Fig.

[0196] 6 schematically shows a close up of the section V of the solid state light source 3, 15, 24 according to Fig. 5.

[0197] At least one of the first solid state light source 3, the second solid state light source 15, and, where provided, the third solid state light source 24 may be a solid state light source according to Figs. 5 and 6.

[0198] The solid state light source 3 according to Figs. 5 and 6 comprises a semiconductor laser diode 31. The semiconductor laser diode 31 is arranged in a casing 33. The casing 33 comprises a light exit window 32.

[0199] A heat sink 34 may be arranged in thermal contact with the semiconductor laser diode 31.

[0200] A metallic strip 40 (cf. Fig. 6) may be provided on the semiconductor laser diode 31.

[0201] A bonding wire 39 may be arranged in physical contact with the semiconductor laser diode 31. Alternatively, the bonding wire 39 may be arranged in physical contact with the metallic strip 40.

[0202] At least one connector pin 37, 38 may be arranged in electrical contact with the semiconductor laser diode 31.

[0203] A photodiode 36 may be provided. The photodiode 36 is configured to monitor the semiconductor laser diode 31.

[0204] A base 35 may be provided. The semiconductor laser diode 31 is arranged on the base 35.

[0205] Referring now to Fig. 7, different suitable phosphors for a light generating system 1 according to the invention will be described.

[0206] Garnet class2024PF80401

[0207] 24

[0208] Generally, garnet class phosphors are suitable for use as a luminescent material for the luminescent element 5. Garnet class phosphors are luminescent materials of the type AsBsO Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials.

[0209] Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B may comprise aluminum (Al); however, in addition to aluminum, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), especially up to about 20% of B, more especially up to about 10 % of B (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and / or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Yi-xLux)3B50i2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1. The term “:Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. For instance, in the case of (Yi-xLux)3A150i2:Ce, part of Y and / or Lu is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.89Ceo.oi)3A150i2. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

[0210] Fig. 7 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 another suitable garnet class phosphor, namely a Yttrium Aluminum Garnet (YAG) phosphor. YAG phosphors are efficient and suitable for creating a high correlated color temperature (CCT). YAG phosphors exhibit absorption peaks at 450 nm, and dominant emission wavelengths range from 540 nm - 560 nm. YAG phosphors can be effectively2024PF80401

[0211] 25

[0212] excited by a 450 nm blue LED chip with an emission peak wavelength in the 540 nm - 560 nm range. YAG phosphors are mainly used for increasing luminous efficiency. By adding a small amount of a YAG yellow phosphor to an Ra80 LED, the luminous flux will increase dramatically. YAG phosphors are particularly suitable for use as a luminescent material for the first luminescent element 5.

[0213] Another suitable garnet class phosphor is a Lutetium Aluminum Garnet (LuAG) phosphor. LuAG phosphors offer performance comparable to YAG phosphors. LuAG phosphors may have dominant emission wavelengths ranging from 520nm to 540 nm. LuAG phosphors are generally used in conjunction with red phosphors for high CRI full spectrum coverage. LuAG phosphors can be effectively excited by a 450nm blue LED with an emission peak wavelength in the 510-540 nm range. Combined with nitride red phosphor, a high CRI spectrum with Ra above 95 can be achieved. LuAG phosphors are particularly suitable for use as a luminescent material for the first luminescent element 5.

[0214] Fig. 8 shows an exemplary lamp 300 comprising a light generating system 100 according to any embodiment of the invention. In the embodiment shown, the light generating system 100 comprises a substantially straight light generating system. The light generating system of such a lamp may in other embodiments be a light generating system with another shape, such as, but not limited to, spiral-shaped, helix-shaped, meandering, twisted, flat and combinations thereof.

[0215] The lamp 300 further comprises a driver or controller 305 configured for controlling the plurality of solid state light sources of the light generating system 100. The controller 305 is configured to power the plurality of solid state light sources via electrical circuitry (not visible on the figures) of the light generating system 100. The light generating system 100 may also comprise a controller 28, which may or may not be separate from the controller 305. In other words, the controller 305 and the controller 28 of the light generating system 100 may be integrated into one and the same driver or controller, or they may be mutually separate units.

[0216] The lamp 300 further comprises an envelope 301 at least partially enveloping the at least one light generating system 100. The lamp 300 further comprises a cap 303. As shown in Fig. 8, 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 it 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.2024PF80401

[0217] 26

[0218] 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.

[0219] Turning finally to Fig. 9, an exemplary luminaire in the form of a pendant 400 is shown. The pendant 400 comprises a light generating system 100 according to any embodiment of the invention. The light generating system 100 is as shown in Fig. 9 provided within a lamp 300 in the form of a light bulb. The light generating system 100 as shown in Fig. 9 comprises a substantially straight light generating system.

[0220] 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 generating system 100. 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.

[0221] The pendant 400 further comprises a socket 401 for connecting the lamp 300, and thereby the light generating system 100, 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.

[0222] The pendant 400 may further comprise a driver 402 configured for controlling the light generating system 100. 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 generating system 100 may also comprise a controller 28, which may or may not be separate from one or both of the driver 402 and the controller 305.

[0223] As shown in Fig. 9, 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 or screen 403. The pendant 400 further comprises an electrical wiring 404 for connection to a source of electricity, such as a mains.

[0224] It is noted that the pendant 400 shown in Fig. 9 is only one example of a luminaire according to the invention. Any suitable type of luminaire may be envisaged, such2024PF80401

[0225] 27

[0226] as but not limited to, luminaires for display applications, such as LED displays, LCD displays and OLED displays, a standing luminaire, a wall hung luminaire, a chandelier, a reading luminaire, an outdoor luminaire, and a table luminaire.

[0227] 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.

[0228] 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

2024PF8040128CLAIMS:

1. A light generating system (1) configured to, in operation, emit system light (2), the light generating system comprising:a first solid state light source (3) configured to, in operation, emit first light source light (4) having a first peak emission wavelength, I, in a wavelength range of 420 nm to 490 nm, the first solid state light source comprising one or more of a laser diode, a super-luminescent diode, and a stacked multi -junction light-emitting diode;a second solid state light source (15) configured to, in operation, emit second light source light (16) having a second peak emission wavelength, X2, in a wavelength range of 600 to 690 nm, or in a wavelength range of 500 nm to 590 nm, the second solid state light source comprising one or more of a laser diode, a super-luminescent diode, and a stacked multi -junction light-emitting diode;a luminescent element (5) comprising a first major surface (51) and a second major surface (52) opposite to the first major surface; andan optical arrangement (20) arranged in front of and remote of the luminescent element (5), the optical arrangement (20) being configured to: (i) receive the first light source light (4) from a first direction, (ii) receive the second light source light (16) from a second direction, (iii) combine the first light source light (4) and the second light source light (16) to form combined light (21), and (iv) redirect the combined light such that the combined light (21) impinges on the luminescent element (5) perpendicular to the first major surface (51) of the luminescent element (5);wherein the luminescent element (5) is arranged downstream of the optical arrangement (20), the luminescent element (5) being configured to convert part of the combined light (21) into converted light (6), the converted light (6) comprising a third peak emission wavelength, X3, being in the range of 500 nm to 590 nm, and wherein the luminescent element further is configured to reflect part of the combined light as reflected combined light (42);wherein the optical arrangement (20) comprises a first specular reflecting element (7) configured to reflect the first light source light (4) and a second optical element (17) configured to reflect the second light source light (16);2024PF8040129wherein the first major surface has a surface area, Al, and wherein the first specular reflecting element has a largest surface area, A2, wherein A2 < O.6*A1,wherein one of the following applies:the second optical element (17) is arranged upstream of the first specular reflecting element (7), the second optical element (17) is arranged to direct the second light source light to the first specular reflecting element (7), and the first specular reflecting element (7) is transparent for the second light source light and configured to combine the first light source light and the second light source light as the combined light (21) and to direct the combined light to the luminescent element (5);the first specular reflecting element (7) is arranged upstream of the second optical element (17), the first specular reflecting element (7) is arranged to direct the first light source light to the second optical element (17), and the second optical element (17) is transparent for the first light source light and configured to combine the first light source light and the second light source light as the combined light (21) and to direct the combined light to the luminescent element (5);wherein the light generating system further comprises a first collimator (11) arranged downstream of the luminescent element and configured to collimate the reflected combined light (42) and the converted light (6);and wherein the system light (2) comprises, in an operational mode, a combination of the reflected combined light (42) and the converted light (6), the system light is white light having a correlated color temperature in a range from 2000K to 9000K and a color rendering index of at least 65.

2. A light generating system according to claim 1, and further comprising a third solid state light source (24) configured to, in operation, emit third light source light (25) having a fourth peak emission wavelength, X4, the third solid state light source comprising one or more of a laser diode, a super-luminescent diode, and a stacked multi -junction lightemitting diode; whereinif the second peak emission wavelength, 2, is in the wavelength range of 600 to 700 nm, the fourth peak emission wavelength, X4, is in the wavelength range of 500 nm to 590 nm, or if the second peak emission wavelength, 2, is in the wavelength range of 500 nm to 590 nm, the fourth peak emission wavelength, X4, is in the wavelength range of 600 to 700 nm, wherein2024PF8040130the optical arrangement (20) further is configured to: (v) receive the third light source light (25) from a third direction, and (vi) combine the first light source light (4), the second light source light (16), and the third light source light (25) to form the combined light (21), whereinthe optical arrangement (20) further comprises a third optical element (30) configured to reflect the third light source light (25),wherein one of the following applies:the third optical element (30) is arranged upstream of the first specular reflecting element (7) and upstream of the second optical element (17), the third optical element (30) is arranged to direct the third light source light (25) to the second optical element (17), the first specular reflecting element (7) and the second optical element (17) are transparent for the third light source light (25), and the first specular reflecting element (7) is configured to combine the first light source light, the second light source light, and the third light source light as the combined light (21) and to direct the combined light to the luminescent element (5);the third optical element (30) is arranged upstream of the first specular reflecting element (7) and upstream of the second optical element (17), the third optical element (30) is arranged to direct the third light source light (25) to the first specular reflecting element (7), the first specular reflecting element (7) and the second optical element (17) are transparent for the third light source light (25), and the second optical element (17) is configured to combine the first light source light, the second light source light, and the third light source light as the combined light (21) and to direct the combined light to the luminescent element (5);the third optical element (30) is arranged between the first specular reflecting element (7) and the second optical element (17), the third optical element (30) is arranged to direct the third light source light (25) to the first specular reflecting element (7), the first specular reflecting element (7) is transparent for the third light source light (25), the third optical element (30) is transparent for the second light source light (16), and the first specular reflecting element (7) is configured to combine the first light source light, the second light source light, and the third light source light as the combined light (21) and to direct the combined light to the luminescent element (5);the third optical element (30) is arranged between the first specular reflecting element (7) and the second optical element (17), the third optical element (30) is arranged to direct the third light source light (25) to the second optical element (17), the second optical2024PF8040131element (17) is transparent for the third light source light (25), the third optical element (30) is transparent for the first light source light (4), and the second optical element (17) is configured to combine the first light source light, the second light source light, and the third light source light as the combined light (21) and to direct the combined light to the luminescent element (5);the third optical element (30) is arranged downstream of the first specular reflecting element (7) and downstream of the second optical element (17), the first specular reflecting element (7) is arranged to direct the first light source light (4) and the second light source light (16) to the third optical element (30), the third optical element (30) is transparent for the first light source light (4) and transparent for the second light source light (16), and the third optical element (30) is configured to combine the first light source light, the second light source light, and the third light source light as the combined light (21) and to direct the combined light to the luminescent element (5);the third optical element (30) is arranged downstream of the first specular reflecting element (7) and downstream of the second optical element (17), the second reflecting element (17) is arranged to direct the second light source light (16) and the first light source light (4) to the third optical element (30), the third optical element (30) is transparent for the first light source light (4) and is transparent for the second light source light (16), and the third optical element (30) is configured to combine the first light source light, the second light source light, and the third light source light as the combined light (21) and to direct the combined light to the luminescent element (5); and whereinthe system light (2) comprises, in an operational mode, a combination of the reflected combined light and the converted light (6).

3. A light generating system according to any one of the above claims, wherein the first specular reflecting element (7), the second optical element (17), and, where provided, the third optical element (30), are specularly reflecting mirrors obliquely arranged with respect the first major surface of the luminescent element.

4. A light generating system according to claim 3, wherein the two or three obliquely arranged specular reflecting elements (7, 17, 30) are arranged (i) vertically stacked and mutually spaced apart, or (ii) crossed, or (iii) mutually spaced apart and forming the respective legs of a V-shape.2024PF80401325. A light generating system according to claim 3 or 4, wherein the first specular reflecting element (7) is a reflective polarizer, and wherein the reflective polarizer is (i) reflective for the first light source light (4), and transmissive for zero, one or both of the second light source light (16) and the third light source light (25), or (ii) transmissive for the first light source light (4) and reflective for zero, one or both of the second light source light (16) and the third light source light (25), or whereinat least one of the specular reflecting elements (7) is a dichroic mirror, and wherein the dichroic mirror is (i) reflective for the first light source light (4), and transmissive for zero, one or both of the second light source light (16) and the third light source light (25), or (ii) transmissive for the first light source light (4) and reflective for zero, one or both of the second light source light (16) and the third light source light (25).

6. A light generating system according to any one of claims 3 to 5, wherein the second optical element (17) is a reflective polarizer, and wherein the reflective polarizer is (i) reflective for the second light source light (16) and transmissive for zero, one or both of the first light source light (4) and the third light source light (25), or (ii) transmissive for the second light source light (16) and reflective for zero, one or both of the first light source light (4) and the third light source light (25), or whereinthe second optical element (17) is a dichroic mirror, and wherein the dichroic mirror is (i) reflective for the second light source light (16) and transmissive for zero, one or both of the first light source light (4) and the third light source light (25), or (ii) transmissive for the second light source light (16) and reflective for zero, one or both of the first light source light (4) and the third light source light (25).

7. A light generating system according to any one of claims 3 to 6, wherein the third optical element (30) is a reflective polarizer, and wherein the reflective polarizer is (i) reflective for the third light source light (25), and transmissive for zero, one or both of the first light source light (4) and the second light source light (16), or (ii) transmissive for the third light source light (30) and reflective for zero, one or both of the first light source light (4) and the second light source light (16), or whereinthe third optical element (30) is a dichroic mirror, and wherein the dichroic mirror is (i) reflective for the third light source light (25) and transmissive for zero, one or both of the first light source light (4) and the second light source light (16), or (ii)2024PF8040133transmissive for the third light source light (25) and reflective for zero, one or both of the first light source light (4) and the second light source light (16).

8. A light generating system according to any one of the above claims, wherein the luminescent element (5) further is configured to diffuse the reflected combined light.

9. A light generating system according to any one of the above claims, wherein a major part of the converted light (6) and a major part of the reflected combined light does not impinge onto the optical arrangement (20).

10. A light generating system according to any one of the above claims, wherein A2 < O.5*A1.

11. A light generating system according to any one of the above claims, and further comprising one or more of:a first further optical element (22) arranged downstream of the first solid state light source (3) and configured to collimate the first light source light (4),a second further optical element (23) arranged downstream of the second solid state light source (15) and configured to collimate the second light source light (16), and when a third solid state light source (24) is provided, a third further optical element (26) arranged downstream of the third solid state light source and configured to collimate the third light source light (25).

12. A light generating system according to any one of the above claims, and further comprising a controller (28) configured to individually control the first solid state light source (3), the second solid state light source (15), and, where provided, the third solid state light source (24).

13. A light generating system according to claim 12, and further comprising a sensor (41) configured to sense an operational parameter of the light generating system (1) and to provide the sensed operational parameter to the controller (28) for controlling the first solid state light source (3), the second solid state light source (15), and, where provided, the third solid state light source (24).2024PF804013414. A light generating system according to any one of the above claims, and further comprising a heat sink element (9), wherein the luminescent element (5) is arranged with the second major surface (52) in thermal contact with the heat sink element (9), wherein one or more of the following applies: (i) an element or layer (10) being reflective to visible light and transmissive to heat is arranged between the luminescent element (5) and the heat sink element (9), and (ii) the heat sink element (9) comprises a reflective material.

15. A lamp or a luminaire comprising a light generating system (1) according to any one of the above claims.

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