A light generating system

Abstract

A light generating system (1) comprising a first solid state light source (3) configured to, in operation, emit first light source light (4); a first polarizing beam splitting element (7) being transmissive or reflective for the first light source light (4); a first X / 4 waveplate (8) configured to change the first light source light (4) into changed first light source light (9); a second solid state light source (5) configured to, in operation, emit second light source light (6); a second polarizing beam splitting element (10) being reflective or transmissive for the second light source light (6); a second X / 4 waveplate (11) configured to change the second light source light (6) into changed second light source light (12); a polarization maintaining diffusing element (13) configured to receive and diffuse the changed first light source light (9) to provide first diffuse light (14), and the changed second light source light (12) to provide second diffuse light (15); a first dichroic element (16) configured to receive and direct the changed first light source light (9) towards the polarization maintaining diffusing element (13), and the changed second light source light (12) towards the polarization maintaining diffusing element (13), and to receive and direct the first diffuse light (14) towards the first X / 4 waveplate (8), and the second diffuse light (15) towards the second X / 4 waveplate (11); and a beam combining element (40, 7, 10) being configured to combine the converted first diffuse light (17) and the converted second diffuse light (18) to form the system light (2).

Description

[0001] 2024PF80403

[0002] A light generating system

[0003] FIELD OF THE INVENTION

[0004] The invention relates to a light generating system comprising a first solid state light source providing first light source light. The invention further relates to a lighting fixture comprising such a light generating system.

[0005] 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] As used herein, the term “red light” is intended to refer to light with a peak wavelength falling within the wavelength interval of 600 to 680 nm.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.2024PF80403

[0016] 2

[0017] 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.

[0018] As used herein, the term “solid state light source” is intended to refer to any solid state light source, including LEDs, laser diodes, super-luminescent diodes, multijunction diodes, a chip on board, and a LED filament.

[0019] BACKGROUND OF THE INVENTION

[0020] Laser-phosphor lighting is used in high-brightness applications such as projection, stage-lighting, search lights and automotive head lights. A recent development in laser lighting is combining laser light of multiple laser wavelengths.

[0021] Laser light can be made eye-safe by using a combination of a polarizing beam splitter, PBS, (or a reflective polarizer), a quarter wavelength (’ / ) plate, suitable lenses and a polarization maintaining diffuser. Because the quarter wavelength plate is optimized for a single wavelength, it can only be used for blue laser light.

[0022] US 2020 / 0186760 Al discloses an illuminator which includes a first laser light source section that outputs a first light flux that belongs to a first wavelength band, a second laser light source section that outputs a second light flux that belongs to a second wavelength band, a third laser light source section that outputs a third light flux that belongs to a third wavelength band and has a polarization direction different from those of the first and second light fluxes, a light combiner that combines the first, second, and third light fluxes to produce combined light, and a predetermined band retardation film on the downstream of the light combiner that changes the phase of a light flux that forms the combined light and belongs to the third wavelength band, and the polarization directions of the light fluxes contained in the combined light are aligned on the downstream of the predetermined band retardation film.

[0023] However, a recent trend in projection is using multiple laser wavelengths, e.g., blue and red laser light combined with green-yellow phosphor light. Another development is combining blue-laser-phosphor light with infrared laser light.

[0024] It is desired to improve the safety, efficiency and / or compactness of high brightness laser light sources capable of combining laser light of multiple laser wavelengths.2024PF80403

[0025] 3

[0026] SUMMARY OF THE INVENTION

[0027] It is an object of the present invention to overcome this problem, and to provide a light generating system, which is capable of combining laser light of multiple laser wavelengths, and which light generating system has one or more of an improved safety, an improved efficiency, and an improved compactness.

[0028] 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, the first light source light having a first peak emission wavelength, XI, in a wavelength range of 600 nm to 680 nm and having a first linear polarization or polarization direction, the first solid-state light source being selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes, a first polarizing beam splitting element being arranged downstream of the first solid-state light source, wherein the first polarizing beam splitting element is (i) transmissive for the first light source light having the first linear polarization, or (ii) reflective for the first light source light having the first linear polarization, a first X / 4 waveplate being arranged downstream of the first polarizing beam splitting element, the first X / 4 waveplate being configured to change the first light source light having the first linear polarization into changed first light source light having a first circular polarization, a second solid state light source configured to, in operation, emit second light source light, the second light source light having a second peak emission wavelength, X2, in a wavelength range of 420 nm to 490 nm and having a second linear polarization or direction, the second solid-state light source being selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes, a second polarizing beam splitting element being arranged downstream of the second solid-state light source, wherein the second polarizing beam splitting element is (i) reflective for the second light source light having the second linear polarization, or (ii) transmissive for the second light source light having the second linear polarization, a second X / 4 waveplate being arranged downstream of the second polarizing beam splitting element, the second X / 4 waveplate being configured to change the second light source light having the second linear polarization into changed second light source light having a second circular polarization, a polarization maintaining diffusing element being arranged downstream of the first X / 4 waveplate and being arranged downstream of the second X / 4 waveplate, the polarization maintaining diffusing element being configured to receive and diffuse the changed first light source light having the first2024PF80403

[0029] 4

[0030] circular polarization to provide first diffuse light having the first circular polarization, and being configured to receive and diffuse the changed second light source light having the second circular polarization to provide second diffuse light having the second circular polarization, a first dichroic element being arranged downstream of the first X / 4 waveplate and being arranged downstream of the second X / 4 waveplate, and being arranged upstream of the polarization maintaining diffusing element, the first dichroic element being configured to (i) receive and direct the changed first light source light having the first circular polarization towards the polarization maintaining diffusing element, (ii) receive and direct the changed second light source light having the second circular polarization towards the polarization maintaining diffusing element, (iii) receive and direct the first diffuse light towards the first X / 4 waveplate, and (iv) receive and direct the second diffuse light towards the second X / 4 waveplate, wherein the first X / 4 waveplate is further configured to convert the first diffuse light having the first circular polarization into converted first diffuse light having the second linear polarization being different from the first linear polarization, wherein the first polarizing beam splitting element further is (i) reflective for the converted first diffuse light having the second linear polarization when being transmissive for the first light source light having the first linear polarization, or (ii) transmissive for the converted first diffuse light having the second linear polarization when being reflective for the first light source light having the first linear polarization, wherein the second X / 4 waveplate is further configured to convert the second diffuse light having the second circular polarization into converted second diffuse light having the first linear polarization being different from the second linear polarization, wherein the second polarizing beam splitting element further is (i) transmissive for the converted second diffuse light having the second linear polarization when being reflective for the second light source light having the first linear polarization, or (ii) reflective for the converted second diffuse light having the second linear polarization when being transmissive for the second light source light having the first linear polarization, wherein the light generating system further comprises a beam combining element being configured to combine the first diffuse light and the second diffuse light, and wherein, in an operational mode of the light generating system, the system light comprises at least the first diffuse light and the second diffuse light.

[0031] Thereby, a light generating system is provided, which is capable of combining laser light of multiple, in this case two, laser wavelengths, and which comprises one or more of an improved safety, an improved efficiency, and an improved compactness.2024PF80403

[0032] 5

[0033] The second polarization may be perpendicular to, such as 90 degrees rotated to, the first linear polarization.

[0034] In an operational mode of the light generating system, the system light comprises the first diffuse light, e.g., having the second linear polarization, and the second diffuse light, e.g., having the second linear polarization.

[0035] The light generating system may further comprise a X / 2 waveplate configured to swap the polarization of the converted first diffuse light and the converted second diffuse light before combining, by the beam combining element, the converted first diffuse light and the converted second diffuse light.

[0036] One of the following may apply: (i) The second polarizing beam splitting element and the beam combining element may be one and the same element, (ii) The first polarizing beam splitting element and the beam combining element may be one and the same element, (iii) The beam combining element may be arranged downstream of the first polarizing beam splitting element and the second polarizing beam splitting element, and the beam combining element is a dichroic element or a reflective polarizer.

[0037] Thereby, a light generating system with a simpler construction is provided for. The second polarizing beam splitting element and the beam combining element may be provided as a dichroic cube.

[0038] Thereby, a light generating system with a particularly simple construction is provided for.

[0039] A first reflecting element may be arranged in a beam path of the converted first diffuse light downstream of the first polarizing beam splitting element, the first reflecting element being configured to direct the converted first diffuse light towards the second polarizing beam splitting element.

[0040] Alternatively, a first reflecting element is arranged in a beam path of the converted second diffuse light downstream of the second polarizing beam splitting element, the first reflecting element being configured to direct the converted second diffuse light towards the first polarizing beam splitting element.

[0041] By providing the above-mentioned first reflecting element, a light generating system is provided, which is capable of combining laser light of multiple laser wavelengths with an improved efficiency.

[0042] The light generating system may further comprise a first optical element arranged between the polarization maintaining diffusing element and the first dichroic element, the first optical element being configured to: (i) focus the changed first light source2024PF80403

[0043] 6

[0044] light and the changed second light source light onto the polarization maintaining diffusing element and (ii) collimate one or more of the first diffuse light and the second diffuse light.

[0045] Thereby, it may be ensured that all or as good as all light, which it is intended to diffuse by the polarization maintaining diffusing element reaches the polarization maintaining diffusing element, and that loss of diffuse light before the diffuse light reaches the first dichroic element may be minimized or avoided altogether.

[0046] The light generating system may further comprise a second optical element arranged downstream of the first solid-state light source and upstream of the first polarizing beam splitting element and being configured to collimate the first light source light.

[0047] Thereby, loss of first light source light before the first light source light reaches the first polarizing beam splitting element may be minimized or avoided altogether.

[0048] The light generating system may further comprise a third optical element arranged downstream of the second solid-state light source and upstream of the second polarizing beam splitting element and being configured to collimate the second light source light.

[0049] Thereby, loss of second light source light before the second light source light reaches the second polarizing beam splitting element may be minimized or avoided altogether.

[0050] The polarization maintaining diffusing element may be arranged on a metallic reflector or a reflective substrate.

[0051] Thereby loss of light otherwise being transmitted through the polarization maintaining diffusing element may be minimized or avoided altogether.

[0052] The light generating system may further comprise a first heat sink element on which the first solid state light source is arranged.

[0053] Thereby, efficient and sufficient cooling of the first solid state light source is provided for, which in turn further improves the quality of the device light emitted by the light generating system.

[0054] The light generating system may further comprise a second heat sink element on which the second solid state light source is arranged.

[0055] Thereby, efficient and sufficient cooling of the second solid state light source is provided for, which in turn further improves the quality of the device light emitted by the light generating system.2024PF80403

[0056] 7

[0057] The metallic reflector or reflective substrate, on which the polarization maintaining diffusing element is arranged may further be configured to act as a heat sink element.

[0058] Thereby, efficient and sufficient cooling of the polarization maintaining diffusing element is provided for, which in turn further improves the quality of the device light emitted by the light generating system.

[0059] The first polarizing beam splitting element may be a polarizing beam splitter for red light or a polarizing reflector. Alternatively, or additionally, the second polarizing beam splitting element may be a polarizing beam splitter for blue light or a polarizing reflector.

[0060] Thereby, a light generating system with a particularly simple first and / or second polarizing beam splitter, and thus a simpler construction, is provided for.

[0061] The light generating system may further comprise: a third solid state light source configured to, in operation, emit third light source light, the third light source light having a third peak emission wavelength, X3, in a wavelength range of 500 nm to 550 nm, and having a third linear polarization, the third solid-state light source being selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes, a third polarizing beam splitting element being arranged downstream of the third solid-state light source, wherein the third polarizing beam splitting element is (i) transmissive for the third light source light having the third linear polarization, or (ii) reflective for the third light source light having the third linear polarization, a third X / 4 waveplate being arranged downstream of the third polarizing beam splitting element, the third / 4 waveplate being configured to change the third light source light having the third linear polarization into changed third light source light having a third circular polarization, wherein the polarization maintaining diffusing element further is arranged downstream of the third X / 4 waveplate, and the polarization maintaining diffusing element further is configured to receive and diffuse the changed third light source light having the third circular polarization to provide third diffuse light having the third circular polarization, a second dichroic element configured to (i) receive and direct the changed third light source light having the third circular polarization towards the polarization maintaining diffusing element, and (ii) receive and direct the third diffuse light having the third circular polarization towards the third X / 4 waveplate, wherein the first dichroic element further is configured to (i) receive and direct the changed third light source light having the third circular polarization towards the polarization maintaining diffusing element, and (ii) receive and direct the third diffuse light having the third circular2024PF80403

[0062] 8

[0063] polarization towards the second dichroic element, wherein the third X / 4 waveplate further is configured to convert the third diffuse light having the third circular polarization into converted third diffuse light having the third linear polarization, wherein the third polarizing beam splitting element further is (i) reflective for the converted third diffuse light having the third linear polarization when being transmissive for the third light source light, or (ii) transmissive for the converted third diffuse light having the third linear polarization when being reflective for the third light source light, wherein a second reflecting element is arranged in a beam path of the converted third diffuse light downstream of the third polarizing beam splitting element, the second reflecting element being configured to direct the converted third diffuse light towards the beam combining element, wherein the beam combining element is configured to combine the converted first diffuse light, the converted second diffuse light, and the converted third diffuse light, and wherein, in an operational mode of the light generating system, the system light comprises at least the converted first diffuse light, the converted second diffuse light, and the converted third diffuse light.

[0064] Thereby, a light generating system is provided, which is capable of combining laser light of multiple, in this case three, laser wavelengths, and which comprises one or more of an improved safety, an improved efficiency, and an improved compactness.

[0065] The light generating system may further comprise a fourth optical element arranged downstream of the third solid-state light source and upstream of the third polarizing beam splitting element and being configured to collimate the third light source light.

[0066] Thereby, loss of third light source light before the third light source light reaches the third polarizing beam splitting element may be minimized or avoided altogether.

[0067] The light generating system may further comprise a third heat sink element on which the third solid state light source is arranged.

[0068] Thereby, efficient and sufficient cooling of the third solid state light source is provided for, which in turn further improves the quality of the device light emitted by the light generating system.

[0069] The light generating system may further comprise a third dichroic element being arranged in a beam path of the converted third diffuse light between the second reflecting element and the beam combining element, the third dichroic element being configured to direct the converted third diffuse light towards the beam combining element.

[0070] The light generating system may further comprise a fourth dichroic element arranged in a beam path of the second diffuse light between the first dichroic element and the2024PF80403

[0071] 9

[0072] second X / 4 waveplate, the fourth dichroic element being configured to direct the second diffuse light towards the second X / 4 waveplate.

[0073] The light generating system may further comprise a third reflecting element arranged in a beam path of the converted second diffuse light downstream of the second polarizing beam splitting element, the third reflecting element being configured to direct the converted second diffuse light towards the beam combining element.

[0074] By providing one or more of the above-mentioned third dichroic element, fourth dichroic element, and third reflecting element, a light generating system is provided, which is capable of combining laser light of multiple laser wavelengths with an improved efficiency.

[0075] The light generating system may further comprise: a fourth solid state light source configured to, in operation, emit fourth light source light, the fourth light source light having a fourth peak emission wavelength, X4, in a wavelength range of 420 nm to 490 nm, the fourth solid-state light source being selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes, a fifth dichroic element being arranged downstream of the fourth solid-state light source, wherein the fifth dichroic element is (i) transmissive for at least a part of the fourth light source light, or (ii) reflective for at least a part of the fourth light source light, depending on the polarization of the fourth light source light, and a luminescent element being arranged downstream of the fifth dichroic element and being configured to convert the fourth light source light into converted light, the converted light comprising a fifth peak emission wavelength, X5, in a wavelength range of 500 nm to 600 nm, wherein the fifth dichroic element further is arranged to receive the converted light and is (i) reflective for the converted light, or (ii) transmissive for the converted light, depending on the polarization of the converted light, wherein the beam combining element further is arranged at or downstream of the fifth dichroic element and is configured to combine the converted first diffuse light, the converted second diffuse light, the converted light, and, where a third light source is provided, the converted third diffuse light, and wherein in an operational mode of the light generating system, the system light comprises at least the converted first diffuse light, the converted second diffuse light, the converted light, and, where a third light source is provided, the converted third diffuse light.

[0076] Thereby, a light generating system is provided, which is capable of combining laser light of multiple, in this case four, laser wavelengths, and which comprises one or more of an improved safety, an improved efficiency, and an improved compactness.2024PF80403

[0077] 10

[0078] The fifth dichroic element and the beam combining element may be provided as a dichroic cube.

[0079] Thereby, a light generating system with a reduced number of components and thus a particularly compact and simple construction is provided for.

[0080] The fifth dichroic element and the beam combining element may be one and the same element.

[0081] Thereby, a light generating system with a more compact and simpler construction is provided for.

[0082] The fifth dichroic element and the beam combining element may be arranged in a distance from one another, and the beam combining element may be a dichroic element.

[0083] Thereby, a light generating system is provided, which is capable of combining laser light of multiple laser wavelengths with one or both of an improved safety and an improved efficiency.

[0084] The light generating system may further comprise a fifth optical element arranged downstream of the luminescent element and upstream of the sixth dichroic element, the fifth optical element being configured to: (i) focus the part of the fourth light source light on the luminescent element and (ii) collimate the converted light.

[0085] Thereby, it may be ensured that all or as good as all light, which it is intended to convert by the luminescent element reaches the luminescent element, and that loss of converted light before the converted light reaches the beam splitting component may be minimized or avoided altogether.

[0086] The light generating system may further comprise a sixth optical element arranged downstream of the fourth solid-state light source and upstream of the fifth dichroic element and being configured to collimate the fourth light source light.

[0087] Thereby, loss of fourth light source light before the fourth light source light reaches the fifth dichroic element may be minimized or avoided altogether.

[0088] The light generating system may further comprise a reflective substrate on which the luminescent element is arranged.

[0089] Thereby loss of light otherwise being transmitted through the luminescent element may be minimized or avoided altogether.

[0090] The light generating system may further comprise a fourth heat sink element on which the fourth solid state light source is arranged.2024PF80403

[0091] 11

[0092] Thereby, efficient and sufficient cooling of the fourth solid state light source is provided for, which in turn further improves the quality of the device light emitted by the light generating system.

[0093] The reflective substrate, on which the luminescent element is arranged, may further be configured to act as a heat sink element.

[0094] Thereby, efficient and sufficient cooling of the luminescent element is provided for, which in turn further improves the quality of the device light emitted by the light generating system.

[0095] 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, where provided the third solid state light source, and where provided the fourth solid state light source in order to vary the spectral power distribution of the system light.

[0096] Thereby, it becomes possible to adapt the obtained device light to various different applications and to the light requirements, and especially spectral power distribution requirements, thereof.

[0097] In an operational mode the system light may be white light having one or more of a correlated color temperature, CCT, in a range of 2000 K to 9000 K, and a color rendering index of at least 80.

[0098] The controller may further be configured to change a correlated color temperature of the system light by an amount being in a range of at least 500 K.

[0099] The light generating system may further comprise a depolarizer configured to depolarize one or more of the first diffuse light, the second diffuse light, and, when provided, the third diffuse light, and, when provided, the converted light in order to generate unpolarized system light.

[0100] The invention further relates to a lamp, a luminaire, a vehicle light, projection device, a search light, or a stage lighting device comprising a light generating system according to the invention.

[0101] It is noted that the invention relates to all possible combinations of features recited in the claims.

[0102] BRIEF DESCRIPTION OF THE DRAWINGS

[0103] 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.2024PF80403

[0104] 12

[0105] Fig. 1 schematically shows an embodiment of a light generation system according to the invention and comprising two solid state light sources.

[0106] Fig. 2 schematically shows another embodiment of a light generation system according to the invention and comprising two solid state light sources.

[0107] Fig. 3 schematically shows another embodiment of a light generation system according to the invention and comprising three solid state light sources.

[0108] Fig. 4 schematically shows another embodiment of a light generation system according to the invention and comprising three solid state light sources.

[0109] Fig. 5 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.

[0110] Fig. 6 shows a schematical side view of a lamp comprising a light generating system according to the invention.

[0111] Fig. 7 shows a schematical side view of a luminaire comprising a lamp and a light generating system filament according to the invention.

[0112] 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.

[0113] DETAILED DESCRIPTION

[0114] 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.

[0115] Fig. 1 schematically shows an embodiment of a light generation system 1 according to the invention and comprising two solid state light sources 3 and 5. The light generating system 1 is configured to, in operation, emit system light 2.

[0116] The light generating system 1 comprises a first solid state light source 3. The first solid state light source 3 is configured to, in operation, emit first light source light 4. The first light source light 4 comprises a first peak emission wavelength, I, in a wavelength range of 600 nm to 680 nm. The first light source light 4 further comprises a first linear2024PF80403

[0117] 13

[0118] polarization. The first light source light 4 is red light. The first solid-state light source 3 may be selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes.

[0119] The light generating system 1 further comprises a first polarizing beam splitting element 7. The first polarizing beam splitting element 7 is arranged downstream of the first solid-state light source 3. The first polarizing beam splitting element 7 may be transmissive for the first light source light 4. Alternatively, the first polarizing beam splitting element 7 may be reflective for the first light source light 4.

[0120] The light generating system 1 further comprises a first X / 4 waveplate 8. The first X / 4 waveplate 8 is arranged downstream of the first polarizing beam splitting element 7. The first X / 4 waveplate 8 is configured to change the first light source light 4 having the first linear polarization into changed first light source light 9 having a first circular polarization.

[0121] The light generating system 1 further comprises a second solid state light source 5. The second solid state light source 5 is configured to, in operation, emit second light source light 6. The second light source light 6 comprises a second peak emission wavelength, X2, in a wavelength range of 420 nm to 490 nm. The second light source light 6 further comprises a second linear polarization. The second light source light 6 is blue light. The second solid-state light source 5 is selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes.

[0122] The light generating system 1 further comprises a second polarizing beam splitting element 10. The second polarizing beam splitting element 10 is arranged downstream of the second solid-state light source 5. The second polarizing beam splitting element 10 may be reflective for the second light source light 6. Alternatively, the second polarizing beam splitting element 10 may be transmissive for the second light source light 6.

[0123] The light generating system 1 further comprises a second X / 4 waveplate 11. The second X / 4 waveplate 11 is arranged downstream of the second polarizing beam splitting element 10. The second X / 4 waveplate 11 is configured to change the second light source light 6 having the second linear polarization into changed second light source light 12 having a second circular polarization.

[0124] The light generating system 1 further comprises a polarization maintaining diffusing element 13. The polarization maintaining diffusing element 13 is arranged downstream of the first X / 4 waveplate 8. The polarization maintaining diffusing element 13 is further arranged downstream of the second X / 4 waveplate 11. The polarization maintaining2024PF80403

[0125] 14

[0126] diffusing element 13 is configured to receive and diffuse the changed first light source light 9 having the first circular polarization to provide first diffuse light 14 having the first circular polarization. The polarization maintaining diffusing element 13 is further configured to receive and diffuse the changed second light source light 12 having the second circular polarization to provide second diffuse light 15 having the second circular polarization.

[0127] The light generating system 1 further comprises a first dichroic element 16. The first dichroic element 16 is arranged downstream of the first X / 4 waveplate 8. The first dichroic element 16 is further arranged downstream of the second X / 4 waveplate 11. The first dichroic element 16 is further arranged upstream of the polarization maintaining diffusing element 13. The first dichroic element 16 is configured to receive and direct the changed first light source light 9 towards the polarization maintaining diffusing element 13. The first dichroic element 16 is further configured to receive and direct the changed second light source light 12 towards the polarization maintaining diffusing element 13. The first dichroic element 16 is further configured to receive and direct the first diffuse light 14 towards the first X / 4 waveplate 8. The first dichroic element 16 is further configured to receive and direct the second diffuse light 15 towards the second X / 4 waveplate 11. The first dichroic element 16 may be a dichroic mirror.

[0128] The first X / 4 waveplate 8 is further configured to receive the first diffuse light 14. The first X / 4 waveplate 8 is further configured to convert the first diffuse light 14 having the first circular polarization into converted first diffuse light 17 having the second linear polarization being different from the first linear polarization.

[0129] The first polarizing beam splitting element 7 is further configured to receive the converted first diffuse light 17. When the first polarizing beam splitting element 7 is transmissive for the first light source light 4 having the first linear polarization, the first polarizing beam splitting element 7 is reflective for the converted first diffuse light 17 having the second linear polarization. Alternatively, when the first polarizing beam splitting element 7 is reflective for the first light source light 4 having the first linear polarization, the first polarizing beam splitting element 7 is transmissive for the converted first diffuse light 17 having the second linear polarization. The first polarizing beam splitting element 7 may for instance be a polarizing beam splitter for red light or a polarizing reflector.

[0130] The second X / 4 waveplate 11 is further configured to convert the second diffuse light 15 having the second circular polarization into converted second diffuse light 18 having the first linear polarization being different from the second linear polarization.2024PF80403

[0131] 15

[0132] The second polarizing beam splitting element 10 is further configured to receive the converted second diffuse light 18. When the second polarizing beam splitting element 10 is reflective for the second light source light 6 having the first linear polarization, the second polarizing beam splitting element 10 is transmissive for the converted second diffuse light 18 having the second linear polarization. Alternatively, when the second polarizing beam splitting element 10 is transmissive for the second light source light 6 having the first linear polarization, the second polarizing beam splitting element 10 is reflective for the converted second diffuse light 18 having the second linear polarization. The second polarizing beam splitting element 10 may for instance be a polarizing beam splitter for blue light or a polarizing reflector.

[0133] Finally, the light generating system 1 further comprises a beam combining element 40, 7, 10. The beam combining element 40, 7, 10 is configured to combine the converted first diffuse light 17 and the converted second diffuse light 18. The second polarizing beam splitting element 10 and the beam combining element 40 may be one and the same element. Alternatively, the first polarizing beam splitting element 7 and the beam combining element 40 may be one and the same element. Alternatively, the beam combining element is arranged downstream of the first polarizing beam splitting element 7, and downstream of the second polarizing beam splitting element 10, and the beam combining element 40 may be a dichroic element or a reflective polarizer.

[0134] In this way, the light generating system 1 is configured to, in an operational mode, provide system light 2 which comprises at least the first converted diffuse light 17 and the converted second diffuse light 18. The system light 2 may for instance be white light having one or more of a correlated color temperature, CCT, in a range of 2000 K to 9000 K, and a color rendering index, CRI, of at least 80.

[0135] As is also shown in Fig. 1, the light generating system 1 further comprises an optional first reflecting element 19. The first reflecting element 19 is arranged in a beam path of the converted first diffuse light 17 downstream of the first polarizing beam splitting element 7. The first reflecting element 19 is configured to direct the converted first diffuse light 17 towards the second polarizing beam splitting element 10. Alternatively, the first reflecting element 19 may be arranged in a beam path of the converted second diffuse light 18 downstream of the second polarizing beam splitting element 10. Then, the first reflecting element 19 is configured to direct the converted second diffuse light 18 towards the first polarizing beam splitting element 7.2024PF80403

[0136] 16

[0137] As is also shown in Fig. 1, the light generating system 1 further comprises an optional first optical element 20. The first optical element 20 is arranged between the polarization maintaining diffusing element 13 and the first dichroic element 16. The first optical element 20 is configured to focus the changed first light source light 9 and the changed second light source light 12 onto the polarization maintaining diffusing element 13. The first optical element 20 is further configured to collimate one or more of the first diffuse light 14 and the second diffuse light 15. The first optical element 20 may comprise one or more lenses 21, 22.

[0138] In Fig. 1 the polarization maintaining diffusing element 13, the first dichroic element 16 and the optional first optical element 20 are shown as mutually separate elements. However, it is also feasible that the polarization maintaining diffusing element 13, the first dichroic element 16 and, where provided, the first optical element 20 may form a single polarization maintaining diffuser arrangement 13, 16, 20.

[0139] It is furthermore feasible that the first dichroic element 16 may be configured to combine the first polarization rotated light 9 and the second polarization rotated light 12 to form combined light 9, 12. The combined light 9, 12 may then be directed onto the polarization maintaining diffusing element 13. The polarization maintaining diffusing element 13 may be configured to diffuse the combined light 9, 12 to provide diffuse combined light 14, 15, and to reflect the diffuse combined light 14, 15 back towards the first dichroic element 16. The first dichroic element 16 may then be configured to split the diffuse combined light 14, 15 into first diffuse light 14 and second diffuse light 15. The first optical element 20 may then be configured to focus the combined light 9, 12 on the polarization maintaining diffusing element 13, and to collimate the diffuse combined light 14, 15.

[0140] As is still further shown in Fig. 1, the light generating system 1 further comprises an optional controller 54. The controller 54 is configured to individually control the first solid state light source 3 and the second solid state light source 5 in order to vary at least the spectral power distribution of the system light. The controller 54 may for instance further be configured to change a correlated color temperature of the system light 2, for example by an amount being in a range of at least 200K, at least 500 K, or at least 800 K.

[0141] As is still further shown in Fig. 1, the light generating system 1 further comprises an optional second optical element 23. The second optical element 23 is arranged downstream of the first solid-state light source 3. The second optical element 23 is further arranged upstream of the first polarizing beam splitting element 7. The second optical element 23 is configured to collimate the first light source light 4.2024PF80403

[0142] 17

[0143] As is still further shown in Fig. 1, the light generating system 1 further comprises an optional third optical element 24. The third optical element 24 is arranged downstream of the second solid-state light source 5. The third optical element 24 is further arranged upstream of the second polarizing beam splitting element 10. The third optical element 24 is configured to collimate the second light source light 6.

[0144] As is still further shown in Fig. 1, the light generating system 1 further comprises an optional metallic reflector or an optional reflective substrate 25. The polarization maintaining diffusing element 13 may be arranged on the metallic reflector reflective substrate 25. The metallic reflector or reflective substrate 25 may further be configured to act as a heat sink element.

[0145] Fig. 2 schematically shows another embodiment of a light generation system 100 according to the invention and comprising two solid state light sources 3 and 5. The light generation system 100 differs from the light generation system 1 shown in Fig. 1 and described above in virtue of the following.

[0146] The light generating system 100 comprises a depolarizer 55. The depolarizer 55 is arranged downstream of the beam combining element 40, 7, 10. The depolarizer 55 is configured to receive the converted first diffuse light 17 and the converted second diffuse light 18. The depolarizer 55 is further configured to depolarize one or more of the converted first diffuse light 17 and the converted second diffuse light 18. Thereby, unpolarized system light 2’ is generated.

[0147] The light generating system 100 further comprises an optional first heat sink element 26. The first solid state light source 3 is arranged on the first heat sink element 26. The first heat sink element 26 is configured to lead heat generated by the first solid state light source 3 away from the first solid state light source 3.

[0148] The light generating system 100 further comprises an optional second heat sink element 27. The second solid state light source 5 is arranged the on second heat sink element 27. The second heat sink element 27 is configured to lead heat generated by the second solid state light source 5 away from the second solid state light source 5.

[0149] Fig. 3 schematically shows another embodiment of a light generation system 101 according to the invention. The light generation system 101 differs from the light generation systems 1 and 100 shown in Figs. 1 and 2 and described above in virtue of the following.

[0150] The light generation system 101 comprises three solid state light sources 3, 5 and 28. More particularly, the light generation system 101 comprises a first solid state light2024PF80403

[0151] 18

[0152] source 3 and a second solid state light source 5 as described above, and furthermore a third solid state light source 28.

[0153] The third solid state light source 28 is configured to, in operation, emit third light source light 29. The third light source light 29 comprises a third peak emission wavelength, X3, in a wavelength range of 500 nm to 550 nm. The third light source light 29 further comprises a third linear polarization. The third light source light 29 is green light. The third solid-state light source 28 may be selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes.

[0154] The light generation system 101 further comprises a third polarizing beam splitting element 30. The third polarizing beam splitting element 30 is arranged downstream of the third solid-state light source 28. The third polarizing beam splitting element 30 may be transmissive for the third light source light 29. Alternatively, the third polarizing beam splitting element 30 may be reflective for the third light source light 29 having the third linear polarization.

[0155] The light generation system 101 further comprises a third X / 4 waveplate 31. The third X / 4 waveplate 31 is arranged downstream of the third polarizing beam splitting element 30. The third X / 4 waveplate 31 is configured to change the third light source light 29 having the third linear polarization into changed third light source light 32 having a third circular polarization.

[0156] The polarization maintaining diffusing element 13 is further arranged downstream of the third X / 4 waveplate 31. The polarization maintaining diffusing element 13 is further configured to receive and diffuse the changed third light source light 32 having the third circular polarization to provide third diffuse light 33 having the third circular polarization.

[0157] The light generation system 101 further comprises a second dichroic element 36. The second dichroic element 36 is configured to receive and direct the changed third light source light 32 towards the polarization maintaining diffusing element 13. The second dichroic element 36 is further configured to receive and direct the third diffuse light 33 towards the third X / 4 waveplate 31. The second dichroic element 36 may be a dichroic mirror.

[0158] The first dichroic element 16 is further configured to receive and direct the changed third light source light 32 towards the polarization maintaining diffusing element 13. The first dichroic element 16 is further configured to receive and direct the third diffuse light 33 towards the second dichroic element 36.2024PF80403

[0159] 19

[0160] The third X / 4 waveplate 31 is further configured to convert the third diffuse light 33 having the third circular polarization into converted third diffuse light 34 having the third linear polarization.

[0161] When the third polarizing beam splitting element 30 is transmissive for the third light source light 29, the third polarizing beam splitting element 30 is further reflective for the converted third diffuse light 34 having the third linear polarization. Alternatively, when the third polarizing beam splitting element 30 is reflective for the third light source light 29, the third polarizing beam splitting element 30 is further transmissive for the converted third diffuse light 34 having the third linear polarization.

[0162] The light generation system 101 further comprises a second reflecting element 38. The second reflecting element 38 is arranged in a beam path of the converted third diffuse light 34 downstream of the third polarizing beam splitting element 30. The second reflecting element 38 is configured to direct the converted third diffuse light 34 towards the beam combining element 40.

[0163] The beam combining element 40, 10 of the light generating system 101 is configured to combine the converted first diffuse light 17, the converted second diffuse light 18, and the converted third diffuse light 34.

[0164] Thus, in an operational mode of the light generating system 101, the system light 2 comprises at least the converted first diffuse light 17, the converted second diffuse light 18, and the converted third diffuse light 34.

[0165] The light generation system 101 further comprises an optional third dichroic element 37. The third dichroic element 37 is arranged in a beam path of the converted third diffuse light 34 between the second reflecting element 38 and the beam combining element 40. The third dichroic element 37 is configured to direct the converted third diffuse light 34 towards the beam combining element 40. The third dichroic element 37 may be a dichroic mirror.

[0166] The light generation system 101 further comprises an optional fourth dichroic element 35. The fourth dichroic element 35 is arranged in a beam path of the second diffuse light 15 between the first dichroic element 16 and the second X / 4 waveplate 11. The fourth dichroic element 35 is configured to direct the second diffuse light 15 towards the second X / 4 waveplate 11. The fourth dichroic element 35 may be a dichroic mirror.

[0167] The light generation system 101 further comprises an optional third reflecting element 39. The third reflecting element 39 is arranged in a beam path of the converted second diffuse light 18 downstream of the second polarizing beam splitting element 10. The2024PF80403

[0168] 20

[0169] third reflecting element 39 is configured to direct the converted second diffuse light 18 towards the beam combining element 40.

[0170] The light generating system 101 further comprises an optional fourth optical element 52. The fourth optical element 52 is arranged downstream of the third solid-state light source 28. The fourth optical element 52 is further arranged upstream of the third polarizing beam splitting element 30. The fourth optical element 52 is configured to collimate the third light source light 29.

[0171] The light generating system 101 further comprises an optional third heat sink element 41. The third solid state light source 28 is arranged on the third heat sink element 41. The third heat sink element 41 is configured to lead heat generated by the third solid state light source 28 away from the third solid state light source 28.

[0172] In Fig. 3 the polarization maintaining diffusing element 13, the first dichroic element 16 and the optional first optical element 20 are shown as mutually separate elements. However, it is also feasible that the polarization maintaining diffusing element 13, the first dichroic element 16 and the optional first optical element 20 may form a single polarization maintaining diffuser arrangement 13, 16, 20.

[0173] It is furthermore feasible that the first dichroic element 16 may be configured to combine the first polarization rotated light 9, the second polarization rotated light 12 and the third polarization rotated light 32 to form combined light 9, 12, 32. The combined light 9, 12, 32 may then be directed onto the polarization maintaining diffusing element 13. The polarization maintaining diffusing element 13 may be configured to diffuse the combined light 9, 12, 32 to provide diffuse combined light 14, 15, 33 and to reflect the diffuse combined light 14, 15, 33 back towards the first dichroic element 16. The first dichroic element 16 may be configured to split the diffuse combined light 14, 15, 33 into first diffuse light 14, and second diffuse light 15, and third diffuse light 33.

[0174] The first optical element 20 may be configured to focus the combined light 9, 12, 32 on the polarization maintaining diffusing element 13, and to collimate the diffuse combined light 14, 15, 33.

[0175] As is still further shown in Fig. 3, the light generating system 101 further comprises an optional controller 54. The controller 54 is configured to individually control the first solid state light source 3, the second solid state light source 5, and the third solid state light source 28 in order to vary at least the spectral power distribution of the system light. The controller may for instance further be configured to change a correlated color2024PF80403

[0176] 21

[0177] temperature of the system light 2, for example by an amount being in a range of at least 200K, at least 500 K, or at least 800 K.

[0178] Fig. 4 schematically shows another embodiment of a light generation system 102 according to the invention. The light generation system 102 differs from the light generation system 101 shown in Fig. 3 and described above in virtue of the following.

[0179] The light generation system 102 comprises three solid state light sources 3, 5 and 42. More particularly, the light generation system 102 comprises a first solid state light source 3 and a second solid state light source 5 as described above, and furthermore a fourth solid state light source 42.

[0180] In the embodiment shown in Fig. 4, the light generation system 102 does not comprise a third solid state light source 28 as described above in relation to Fig. 3.

[0181] Nevertheless, it is feasible to provide a light generation system 102 with such a third solid state light source 28, such that in this case the light generation system 102 will comprise a total of four solid state light sources 3, 5, 28 and 42.

[0182] The fourth solid state light source 42 is configured to, in operation, emit fourth light source light 43. The fourth light source light 43 comprises a fourth peak emission wavelength, X4, in a wavelength range of 420 nm to 490 nm. The fourth light source light 43 is blue light. The fourth solid-state light source 42 may be selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes.

[0183] The light generation system 102 further comprises a fifth dichroic element 44. The fifth dichroic element 44 is arranged downstream of the fourth solid-state light source 42. The fifth dichroic element 44 may be transmissive for at least a part of the fourth light source light 43, or the fifth dichroic element 44 may be reflective for at least a part of the fourth light source light 43, depending on the polarization of the fourth light source light 43.

[0184] The light generation system 102 further comprises a luminescent element 45. The luminescent element 45 is arranged downstream of the fifth dichroic element 44. The luminescent element 45 is configured to convert the fourth light source light 43 into converted light 46. The converted light 46 comprises a fifth peak emission wavelength, 5, in a wavelength range of 500 nm to 600 nm. The converted light 46 may be green light, greenyellow light, yellow light, or yellow-orange light.

[0185] The fifth dichroic element 44 is further arranged to receive the converted light 46. Depending on the polarization of the converted light 46, the fifth dichroic element 44 is either reflective for the converted light 46, or transmissive for the converted light 46.2024PF80403

[0186] 22

[0187] The beam combining element 40 is further arranged at or downstream of the fifth dichroic element 44. The beam combining element 40 is further configured to combine the converted first diffuse light 17, the converted second diffuse light 18, the converted light 46, and, where a third light source 28 is provided, the converted third diffuse light 34. The fifth dichroic element 44 and the beam combining element 40 may be one and the same element. The fifth dichroic element 44 and the beam combining element 40 may for instance be provided as a dichroic cube. Alternatively, the fifth dichroic element 44 and the beam combining element 40 may be arranged in a distance from one another, and the beam combining element 40 may be a dichroic element.

[0188] In an operational mode of the light generating system 102, the system light 2 thus comprises at least the converted first diffuse light 17, the converted second diffuse light 18, the converted light 46, and, where a third light source 28 is provided, the converted third diffuse light 34.

[0189] The luminescent element 45 may for instance be a garnet class phosphor, or the luminescent element 45 may comprise a luminescent material in the form of a garnet class phosphor. 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. 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 larger2024PF80403

[0190] 23

[0191] 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.

[0192] Fig. 5 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 effectively 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 luminescent element 45, or as the luminescent element 45.

[0193] 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 luminescent element 45, or as the luminescent element 45.

[0194] The light generating system 102 further comprises an optional fifth optical element 47. The fifth optical element 47 is arranged downstream of the luminescent element 45. The fifth optical element 47 is further arranged upstream of the fifth dichroic element 44. The fifth optical element 47 is configured to focus the part of the fourth light source light 43 on the luminescent element 45. The fifth optical element 47 is further configured to collimate the converted light 46. The fifth optical element 47 may comprise one or more lenses 48, 49.2024PF80403

[0195] 24

[0196] As is shown in Fig. 4, the light generating system 102 further comprises an optional controller 54. The controller 54 is configured to individually control the first solid state light source 3, the second solid state light source 5, the fourth solid state light source 42, and, if provided, the third solid state light source 28, in order to vary at least the spectral power distribution of the system light. The controller may for instance further be configured to change a correlated color temperature of the system light 2, for example by an amount being in a range of at least 200K, at least 500 K, or at least 800 K.

[0197] As is also shown in Fig. 4, the light generating system 102 further comprises an optional sixth optical element 53. The sixth optical element 53 is arranged downstream of the fourth solid-state light source 42. The sixth optical element 53 is further arranged upstream of the fifth dichroic element 44. The sixth optical element 53 is configured to collimate the fourth light source light 43.

[0198] As is also shown in Fig. 4, the light generating system 102 further comprises an optional reflective substrate 50 on which the luminescent element 45 is arranged. The reflective substrate 50 may further be configured to lead heat generated by or in the luminescent element 45 away from the luminescent element 45. Thereby, the reflective substrate 50 acts as a heat sink element.

[0199] The light generating system 102 further comprises an optional fourth heat sink element 51. The fourth solid state light source 42 is arranged on the fourth heat sink element 51. The fourth heat sink element 51 is configured to lead heat generated by the fourth solid state light source 42 away from the fourth solid state light source 42.

[0200] Fig. 6 shows an exemplary lamp 300 comprising a light generating system 1, 100, 101, 102 according to any embodiment of the invention. In the embodiment shown, the light generating system 1, 100, 101, 102 comprises a substantially straight light generating system, such as a light generating system 1, 100, 101, 102 in the form of a LED filament. 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.

[0201] The lamp 300 further comprises a driver or controller 305 configured for controlling the solid state light sources 4, 15 of the light generating system 1, 100, 101, 102. The controller 305 is configured to power the solid state light sources 4, 15 via electrical circuitry (not visible on the figures) of the light generating system 1, 100, 101, 102. The light generating system 1, 100, 101, 102 may also comprise a controller 54, which may or may not be separate from the controller 305. In other words, the controller 305 and the controller 542024PF80403

[0202] 25

[0203] of the light generating system 1, 100, 101, 102 may be integrated into one and the same driver or controller, or they may be mutually separate units.

[0204] The lamp 300 further comprises an envelope 301 at least partially enveloping the at least one light generating system 1, 100, 101, 102. The lamp 300 further comprises a cap 303. As shown in Fig. 6, 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.

[0205] 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.

[0206] Turning finally to Fig. 7, an exemplary luminaire in the form of a pendant 400 is shown. The pendant 400 comprises a light generating system 1, 100, 101, 102 according to any embodiment of the invention. The light generating system 1, 100, 101, 102 is as shown in Fig. 7 provided within a lamp 300 in the form of a light bulb. The light generating system 1, 100, 101, 102 as shown in Fig. 7 comprises a substantially straight light generating system, such as a light generating system 1, 100, 101, 102 in the form of a LED filament.

[0207] 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 1, 100, 101, 102. The transparent envelope may be shaped in any feasible shape, for example such as to resemble the shape of any one of a standard light bulb, a globe light bulb, a candlelight bulb, a customized light bulb and even a spiral light bulb. The transparent envelope may comprise a luminescent material. The transparent envelope may be a glass envelope.

[0208] The pendant 400 further comprises a socket 401 for connecting the lamp 300, and thereby the light generating system 1, 100, 101, 102, to the pendant 400. The socket 401 is adapted to cooperate with the base 303 of the lamp 300. The socket 401 may comprise a threading adapted to cooperate with the threading 302 of the lamp 300. The socket 401 may comprise a terminal adapted to cooperate with the terminal 304 of the lamp 300. The pendant 400 further comprises a reflector or screen 403.

[0209] The pendant 400 may further comprise a driver 402 configured for controlling the light generating system 1, 100, 101, 102. The driver 402 may or may not be the same unit as the controller 305 described above. In other words, the driver 402 and the controller 305 may be integrated into one and the same driver or controller, or they may be mutually2024PF80403

[0210] 26

[0211] separate units. Alternatively, or additionally, the light generating system 1, 100, 101, 102 may also comprise a controller 54, which may or may not be separate from one or both of the driver 402 and the controller 305.

[0212] As shown in Fig. 7, 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.

[0213] It is noted that the pendant 400 shown in Fig. 7 is only one example of a luminaire according to the invention. Any suitable type of luminaire may be envisaged, such as but not limited to, 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.

[0214] 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.

[0215] 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

2024PF8040327CLAIMS:

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), the first light source light (4) having a first peak emission wavelength, XI, in a wavelength range of 600 nm to 680 nm and having a first linear polarization, the first solid-state light source (3) being selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes,a first polarizing beam splitting element (7) being arranged downstream of the first solid-state light source (3), wherein the first polarizing beam splitting element (7) is (i) transmissive for the first light source light (4) having the first linear polarization, or (ii) reflective for the first light source light (4) having the first linear polarization,a first X / 4 waveplate (8) being arranged downstream of the first polarizing beam splitting element (7), the first X / 4 waveplate (8) being configured to change the first light source light (4) having the first linear polarization into changed first light source light (9) having a first circular polarization,a second solid state light source (5) configured to, in operation, emit second light source light (6), the second light source light (6) having a second peak emission wavelength, X2, in a wavelength range of 420 nm to 490 nm and having a second linear polarization, the second solid-state light source (5) being selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes,a second polarizing beam splitting element (10) being arranged downstream of the second solid-state light source (5), wherein the second polarizing beam splitting element (10) is (i) reflective for the second light source light (6) having the second linear polarization, or (ii) transmissive for the second light source light (6) having the second linear polarization, a second X / 4 waveplate (11) being arranged downstream of the second polarizing beam splitting element (10), the second X / 4 waveplate (11) being configured to change the second light source light (6) having the second linear polarization into changed second light source light (12) having a second circular polarization,2024PF8040328a polarization maintaining diffusing element (13) being arranged downstream of the first X / 4 waveplate (8) and being arranged downstream of the second X / 4 waveplate (11), the polarization maintaining diffusing element (13) being configured to receive and diffuse the changed first light source light (9) having the first circular polarization to provide first diffuse light (14) having the first circular polarization, and being configured to receive and diffuse the changed second light source light (12) having the second circular polarization to provide second diffuse light (15) having the second circular polarization,a first dichroic element (16) being arranged downstream of the first X / 4 waveplate (8) and being arranged downstream of the second X / 4 waveplate (11), and being arranged upstream of the polarization maintaining diffusing element (13), the first dichroic element (16) being configured to (i) receive and direct the changed first light source light (9) having the first circular polarization towards the polarization maintaining diffusing element (13), (ii) receive and direct the changed second light source light (12) having the second circular polarization towards the polarization maintaining diffusing element (13), (iii) receive and direct the first diffuse light (14) towards the first X / 4 waveplate (8), and (iv) receive and direct the second diffuse light (15) towards the second X / 4 waveplate (11), whereinthe first X / 4 waveplate (8) is further configured to convert the first diffuse light (14) having the first circular polarization into converted first diffuse light (17) having the second linear polarization being different from the first linear polarization, whereinthe first polarizing beam splitting element (7) further is (i) reflective for the converted first diffuse light (17) having the second linear polarization when being transmissive for the first light source light (4) having the first linear polarization, or (ii) transmissive for the converted first diffuse light (17) having the second linear polarization when being reflective for the first light source light (4) having the first linear polarization, whereinthe second X / 4 waveplate (11) is further configured to convert the second diffuse light (15) having the second circular polarization into converted second diffuse light (18) having the first linear polarization being different from the second linear polarization, whereinthe second polarizing beam splitting element (10) further is (i) transmissive for the converted second diffuse light (18) having the second linear polarization when being reflective for the second light source light (6) having the first linear polarization, or (ii) reflective for the converted second diffuse light (18) having the second linear polarization2024PF8040329when being transmissive for the second light source light (6) having the first linear polarization, whereinthe light generating system (1) further comprises a beam combining element (40, 7, 10) being configured to combine the converted first diffuse light (17) and the converted second diffuse light (18), and wherein,in an operational mode of the light generating system, the system light (2) comprises at least the converted first diffuse light (17) and the converted second diffuse light (18).

2. A light generating system according to claim 1, wherein one of the following applies:(i) the second polarizing beam splitting element (10) and the beam combining element (40) are one and the same element,(ii) the first polarizing beam splitting element (7) and the beam combining element (40) are one and the same element,(iii) the beam combining element (40) is arranged downstream of the first polarizing beam splitting element (7) and the second polarizing beam splitting element (10), and the beam combining element (40) is a dichroic element or a reflective polarizer.

3. A light generating system according to claim 1 or 2, wherein (i) a first reflecting element (19) is arranged in a beam path of the converted first diffuse light (17) downstream of the first polarizing beam splitting element (7), the first reflecting element (19) being configured to direct the converted first diffuse light (17) towards the second polarizing beam splitting element (10), or (ii) a first reflecting element (19) is arranged in a beam path of the converted second diffuse light (18) downstream of the second polarizing beam splitting element (10), the first reflecting element (19) being configured to direct the converted second diffuse light (18) towards the first polarizing beam splitting element (7).

4. A light generating system according to any one of the above claims, and further comprising a first optical element (20) arranged between the polarization maintaining diffusing element (13) and the first dichroic element (16), the first optical element (20) being configured to: (i) focus the changed first light source light (9) and the changed second light source light (12) onto the polarization maintaining diffusing element (13) and (ii) collimate the first diffuse light (14) and the second diffuse light (15).2024PF80403305. A light generating system according to any one of the above claims, wherein (i) the first polarizing beam splitting element (7) is a polarizing beam splitter for red light or a polarizing reflector and / or (ii) the second polarizing beam splitting element (10) is a polarizing beam splitter for blue light or a polarizing reflector.

6. A light generating system according to any one of the above claims, and further comprising:a third solid state light source (28) configured to, in operation, emit third light source light (29), the third light source light (29) having a third peak emission wavelength, X3, in a wavelength range of 500 nm to 550 nm, and having a third linear polarization, the third solid-state light source (28) being selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes,a third polarizing beam splitting element (30) being arranged downstream of the third solid-state light source (28), wherein the third polarizing beam splitting element (30) is (i) transmissive for the third light source light (29) having the third linear polarization, or (ii) reflective for the third light source light (29) having the third linear polarization,a third X / 4 waveplate (31) being arranged downstream of the third polarizing beam splitting element (30), the third X 4 waveplate (31) being configured to change the third light source light (29) having the third linear polarization into changed third light source light (32) having a third circular polarization, whereinthe polarization maintaining diffusing element (13) further is arranged downstream of the third X / 4 waveplate (31), and the polarization maintaining diffusing element (13) further is configured to receive and diffuse the changed third light source light (32) having the third circular polarization to provide third diffuse light (33) having the third circular polarization,a second dichroic element (36) configured to (i) receive and direct the changed third light source light (32) having the third circular polarization towards the polarization maintaining diffusing element (13), and (ii) receive and direct the third diffuse light (33) having the third circular polarization towards the third X / 4 waveplate (31), whereinthe first dichroic element (16) further is configured to (i) receive and direct the changed third light source light (32) having the third circular polarization towards the polarization maintaining diffusing element (13), and (ii) receive and direct the third diffuse2024PF8040331light (33) having the third circular polarization towards the second dichroic element (36), whereinthe third X / 4 waveplate (31) further is configured to convert the third diffuse light (33) having the third circular polarization into converted third diffuse light (34) having the third linear polarization, whereinthe third polarizing beam splitting element (30) further is (i) reflective for the converted third diffuse light (34) having the third linear polarization when being transmissive for the third light source light (29), or (ii) transmissive for the converted third diffuse light (34) having the third linear polarization when being reflective for the third light source light (29), whereina second reflecting element (38) is arranged in a beam path of the converted third diffuse light (34) downstream of the third polarizing beam splitting element (30), the second reflecting element (38) being configured to direct the converted third diffuse light (34) towards the beam combining element (40), whereinthe beam combining element (40, 10) is configured to combine the converted first diffuse light (17), the converted second diffuse light (18), and the converted third diffuse light (34), and wherein,in an operational mode of the light generating system, the system light (2) comprises at least the converted first diffuse light (17), the converted second diffuse light (18), and the converted third diffuse light (34).

7. A light generating system according to claim 6, and further comprising one or more of:(i) a third dichroic element (37) is arranged in a beam path of the converted third diffuse light (34) between the second reflecting element (38) and the beam combining element (40), the third dichroic element (37) being configured to direct the converted third diffuse light (34) towards the beam combining element (40, 7, 10),(ii) a fourth dichroic element (35) arranged in a beam path of the second diffuse light (15) between the first dichroic element (16) and the second X / 4 waveplate (11), the fourth dichroic element (35) being configured to direct the second diffuse light (15) towards the second X / 4 waveplate (11), and(iii) a third reflecting element (39) arranged in a beam path of the converted second diffuse light (18) downstream of the second polarizing beam splitting element (10), the third2024PF8040332reflecting element (39) being configured to direct the converted second diffuse light (18) towards the beam combining element (40, 10).

8. A light generating system according to any one of the above claims, and further comprising:a fourth solid state light source (42) configured to, in operation, emit fourth light source light (43), the fourth light source light (43) having a fourth peak emission wavelength, X4, in a wavelength range of 420 nm to 490 nm, the fourth solid-state light source (42) being selected from the group of laser diodes, super-luminescent diodes, and multi -junction diodes,a fifth dichroic element (44) being arranged downstream of the fourth solid-state light source (42), wherein the fifth dichroic element (44) is (i) transmissive for at least a part of the fourth light source light (43), or (ii) reflective for at least a part of the fourth light source light (43), depending on the polarization of the fourth light source light, anda luminescent element (45) being arranged downstream of the fifth dichroic element (44) and being configured to convert the fourth light source light (43) into converted light (46), the converted light comprising a fifth peak emission wavelength, 5, in a wavelength range of 500 nm to 600 nm, whereinthe fifth dichroic element (44) further is arranged to receive the converted light (46) and is (i) reflective for the converted light (46), or (ii) transmissive for the converted light (46), depending on the polarization of the converted light, whereinthe beam combining element (40) further is arranged at or downstream of the fifth dichroic element (44) and is configured to combine the converted first diffuse light (17), the converted second diffuse light (18), the converted light (46), and, where a third light source (28) is provided, the converted third diffuse light (34), and whereinin an operational mode of the light generating system, the system light (2) comprises at least the converted first diffuse light (17), the converted second diffuse light (18), the converted light (46), and, where a third light source (28) is provided, the converted third diffuse light (34).

9. A light generating system according to claim 8, wherein the fifth dichroic element (44) and the beam combining element (40) are one and the same element, or2024PF8040333wherein the fifth dichroic element (44) and the beam combining element (40) are arranged in a distance from one another, and wherein the beam combining element (40) is a dichroic element.

10. A light generating system according to claim 8 or 9, and further comprising a fifth optical element (47) arranged downstream of the luminescent element (45) and upstream of the fifth dichroic element (44), the fifth optical element (47) being configured to: (i) focus the part of the fourth light source light (43) on the luminescent element (45) and (ii) collimate the converted light (46).

11. A light generating system according to any one of the above claims, and further comprising a controller (54) configured to individually control the first solid state light source (3), the second solid state light source (5), where provided the third solid state light source (28), and where provided the fourth solid state light source (42) in order to vary the spectral power distribution of the system light.

12. A light generating system according to any one of the above claims, wherein in an operational mode the system light (2) is white light having one or more of a correlated color temperature, CCT, in a range of 2000 K to 9000 K, and a color rendering index of at least 80.

13. A light generating system according to claim 11 or 12, wherein the controller is configured to change a correlated color temperature of the system light (2) by an amount being in a range of at least 500 K.

14. A light generating system according to any one of the above claims, wherein the light generating system further comprises a depolarizer (55) configured to depolarize one or more of the converted first diffuse light (17), the converted second diffuse light (18), and, when provided, the third diffuse light (33), and, when provided, the converted light (46) in order to generate unpolarized system light.

15. A lamp, a luminaire, a vehicle light, projection device, a search light, or a stage lighting device comprising a light generating system (1) according to any one of the above claims.

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