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EP-4649259-B1 - LASER-PHOSPHOR BASED STAGE LIGHTING ENGINE WITH A HIGHLY EFFICIENT POLARIZATION MAINTAINING DIFFUSER CONFIGURATION

EP4649259B1EP 4649259 B1EP4649259 B1EP 4649259B1EP-4649259-B1

Inventors

  • HIKMET, RIFAT, ATA, MUSTAFA
  • VAN BOMMEL, TIES

Dates

Publication Date
20260513
Application Date
20240109

Claims (15)

  1. A light generating system (1000) comprising (i) one or more light generating devices (100), (ii) a luminescence conversion arrangement (2000), and (iii) a diffuser arrangement (4000), wherein: - the one or more light generating devices (100) are configured to generate device light (101); wherein the one or more light generating devices (100) comprises a solid state light source (10), wherein the solid state light source (10) comprises one or more of a laser diode and a superluminescent diode; wherein the light generating system (1000) is configured such that, in an operational mode of the light generating system (1000), (a) at least part of the device light (101) propagates to the luminescence conversion arrangement (2000), and (b) at least part of the device light (101) propagates to the diffuser arrangement (4000); wherein the at least part of the device light (101) propagating to the diffuser arrangement (4000) is polarized light comprising one of a first linear polarization and a second linear polarization; - the luminescence conversion arrangement (2000) comprises a luminescent material (200) configured to convert at least part of the device light (101) received by the luminescent material (200) into luminescent material light (201); wherein the luminescent material (200) is configured in the reflective mode relative to device light (101) irradiating the luminescent material (200); - the diffuser arrangement (4000) is configured to generate diffused device light (401) from at least part of the device light (101) received by the diffuser arrangement (4000); wherein the diffuser arrangement (4000) comprises a polarizing beam splitter (410), a quarter wave plate (420), a polarization maintaining diffuser (430), and a specularly reflective mirror (440), wherein the mirror (440) comprises a metallic mirror (440); - the polarizing beam splitter (410) is (i) transmissive for one of the light having the first linear polarization and light having the second linear polarization and (ii) reflective for the other one of the light having the first polarization and the light having the second linear polarization; - the quarter wave plate (420) is configured between the polarizing beam splitter (410) and the polarization maintaining diffuser (430); the polarization maintaining diffuser (430) is configured between the quarter wave plate (420) and the specularly reflective metallic mirror (440); wherein the polarization maintaining diffuser (430) is configured as a diffusor for device light (101) having a polarization imposed by the quarter wave plate (420) to the device light (101); - one or more second optical elements (460) are configured to collimate device light (101), wherein one or more of the following applies: (i) a primary second optical element (460) is configured between the one or more light generating devices (100) and the luminescent material (200), and (ii) a secondary second optical element (460) is configured between the waveplate (420) and the diffuser (430); and - the light generating system (1000) is configured to generate system light (1001) comprising in the operational mode of the light generating system (1000) (i) the diffused device light (401) and (ii) the luminescent material light (201).
  2. The light generating system (1000) according to claim 1, wherein the mirror (440) comprises a planar mirror, wherein the diffuser arrangement (4000) comprises a first optical element (450), wherein the first optical element (450) is configured between the polarization maintaining diffuser (430) and the mirror (440), wherein the first optical element (450) is configured to collimate at least part of the diffused device light (401) into a beam perpendicular to the mirror (440), wherein the first optical element (450) comprises a lens.
  3. The light generating system (1000) according to claim 1, wherein the mirror (440) comprises a curved mirror (440), wherein at least part of the diffused device light (401) is perpendicularly reflected off the curved mirror (440).
  4. The light generating system (1000) according to any one of the preceding claims, wherein polarized light comprising the first polarization is linearly polarized light, wherein polarized light comprising the first polarization comprises one of p-polarization and s-polarization, and wherein the polarized light comprising the second polarization is linearly polarized light, wherein polarized light comprising the second polarization comprises the other one of p-polarization and s-polarization.
  5. The light generating system (1000) according to any one of the preceding claims, wherein the polarization maintaining diffuser (430) comprises an optically isotropic material.
  6. The light generating system (1000) according to any one of the preceding claims, wherein one of the following applies: (i) the polarizing beam splitter (410) is configured to transmit the device light (101) having the first linear polarization; the quarter wave plate (420) is configured to convert transmitted device light having the first linear polarization into first circularly polarized light having a first handedness; the specularly reflective metallic mirror (440) is configured to reflect the first circularly polarized light having the first handedness into second circularly polarized light having a second handedness; the quarter wave plate (420) is configured to convert second circularly polarized light having the second handedness into device light having a second linear polarization, wherein the device light having the second linear polarization is 90° rotated with respect to the device light having the first linear polarization; the polarizing beam splitter (410) is configured to reflect the device light having the second linear polarization; (ii) the polarizing beam splitter (410) is configured to reflect the device light having the first linear polarization; the quarter wave plate (420) is configured to convert reflected device light having the first linear polarization into first circularly polarized light having a first handedness; the specularly reflective metallic mirror (440) is configured to reflect the first circularly polarized light having the first handedness into second circularly polarized light having a second handedness; the quarter wave plate (420) is configured to convert second circularly polarized light having the second handedness into device light having the second linear polarization, wherein the device light having the second linear polarization is 90° rotated with respect to the device light having the first linear polarization; and the polarizing beam splitter (410) is configured to transmit the device light having the second linear polarization.
  7. The light generating system (1000) according to any one of the preceding claims, wherein the luminescence conversion arrangement (2000) further comprises a dichroic reflector (240) configured downstream of one or more of the light generating devices (100), wherein the dichroic reflector (240) is configured to transmit device light (101) and to reflect luminescent material light (201), and wherein the primary second optical element (460) is configured between the dichroic reflector (240) and the luminescent material (200).
  8. The light generating system (1000) according to any one of the preceding claims, wherein the one or more light generating devices (100) comprise a first light generating device (110) and a second light generating device (120), wherein the first light generating device (110) is configured to generate first device light (111), wherein the second light generating device (120) is configured to generate second device light (121), wherein the luminescence conversion arrangement (2000) is configured in a light-receiving relationship with the first light generating device (110), wherein the diffuser arrangement (4000) is configured in a light-receiving relationship with the second light generating device (120).
  9. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) further comprises a rotatable device (250), wherein the rotatable device (250) is configured to support the luminescent material (200); wherein the rotatable device (250) comprises a thermally conductive material.
  10. The light generating system (1000) according to any one of the preceding claims, wherein the device light (101) at least comprises blue light; wherein the luminescent material (200) comprises a first luminescent material (210) configured to generate first luminescent material light (211) having spectral power at one or more wavelengths in the green-yellow wavelength range; wherein the first luminescent material (210) is of the type A 3 B 5 O 12 :Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc.
  11. The light generating system (1000) according to claim 10, wherein the light generating system (1000) comprises a second luminescent material (220) configured to convert at least part of the device light (101) into second luminescent material (221) having a spectral power distribution different from the first luminescent material light (211); wherein the second luminescent material light (221) has spectral power at one or more wavelengths in the orange-red wavelength range.
  12. The light generating system (1000) according to any one of the preceding claims, wherein luminescence conversion arrangement (2000) comprises two or more luminescent materials (210, 220, ...), wherein the two or more luminescent materials (210, 220, ...) are selected from the group comprising a yellow luminescent material, a red luminescent material, and a green luminescent material.
  13. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprises a first diffuser arrangement (4100) and a second diffuser arrangement (4200), wherein: - the one or more light generating devices (100) comprise a first light generating device (110), a second light generating device (120), and a third light generating device (130), wherein the first light generating device (110) is configured to generate first device light (111), wherein the second light generating device (120) is configured to generate second device light (121), wherein the third light generating device is configured to generate third device light (131); - the luminescence conversion arrangement (2000) is configured in a light-receiving relationship with the first light generating device (110), and configured to provide the luminescent material light (201); - the first diffuser arrangement (4100) is configured in a light-receiving relationship with the second light generating device (120), and configured to provide the diffused device light (401); - the second diffuser arrangement (4200) is configured in a light-receiving relationship with the third light generating device (130); wherein the second diffuser arrangement (4200) is configured to generate diffused third device light (401') from at least part of the second device light (121) received by the second diffuser arrangement (4200); - the light generating system (1000) is configured to generate system light (1001) comprising in the operational mode of the light generating system (1000) (i) the diffused device light (401), (ii) the luminescent material light (201), and (iii) the diffused third device light (401').
  14. The light generating system (1000) according to any one of the preceding claims, wherein the system light (1001) comprises in the operational mode of the light generating system (1000) white light having a correlated color temperature in a range from 2000 K to 10000 K and a color rendering index of at least 80; and wherein the solid state light source (10) comprises a laser diode.
  15. A lighting device (1200) selected from the group of a lamp (1), a luminaire (2), a projector device (3), and a stage-lighting device, comprising the light generating system (1000) according to any one of the preceding claims.

Description

FIELD OF THE INVENTION The invention relates to a light generating system. The invention further relates to a lighting device comprising such light generating system. BACKGROUND OF THE INVENTION Laser-phosphor based stage lighting engines are known in the art. For instance, WO2022143318 describes a light emitting device, comprising a first light source, a second light source, a dichroic mirror, a wavelength conversion apparatus, a first light path adjusting apparatus or a second light path adjusting apparatus, and a first scattering optical system. In the present invention, the light mixing effect of emergent light can be improved by using the first scattering optical system. The color temperature of the emergent light of the light emitting device can be freely adjusted by independently adjusting the power of the first light source and the power of the second light source. A laser capable of emitting light of different dominant wavelengths can be used in the second light source to improve the color rendering index of the emergent light of the light emitting device. Light emitted by the first light source in the present invention is all used for exciting the wavelength conversion apparatus. Compared with existing technical solutions, the light emitting device provided by the present invention can achieve output of higher light flux in the case that an optical expansion amount is not increased, and if a polarization selection element is used in the first light source in a matching mode, the output of light flux of the light emitting device can be further improved. SUMMARY OF THE INVENTION High brightness light sources can be used in various applications including spots, stage-lighting, headlamps, home and office lighting, and automotive lighting. For this purpose, laser-phosphor technology can be used, wherein a laser provides laser light and a remote phosphor converts laser light into converted light. A relatively straightforward way to produce white light using lasers is to use blue laser light in combination with phosphor converted light to produce white light. However, current laser lighting fixtures may be unable to produce a safe and high-performance strong beam of light. For instance, a damage of optics may lead to outcoupling of high intensity light. Other problems associated with such laser light sources may come with the desire to create compact high-power devices. Hence, it is an aspect of the invention to provide an alternative light generating system, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. According to a first aspect, the invention provides a light generating system according to claim 1. With the invention, high intensity white light may be provided. Furthermore, the invention may enable generation of high intensity light with a reduced risk that such light escapes from the system when an optical component is broken or damaged. Hence, with the proposed system it may be possible to improve the safety of the laser light generating system. In this way, the invention may provide a laser-phosphor based stage lighting engine with a highly efficient polarization maintaining diffuser configuration. As mentioned before, the invention provides a light generating system comprising, in embodiments, one or more light generating devices, a luminescence conversion arrangement, and a diffuser arrangement. Here below, embodiments of these elements are described in more detail. Herein, the luminescent material light may especially have a different wavelength from the device light, e.g. the luminescent material light may have a wavelength in the yellow wavelength range and the device light may have a wavelength in the blue wavelength range. Furthermore, in embodiments, the luminescent material may especially be configured in the reflective mode relative to device light irradiating the luminescent material. Herein, when an element is indicated to be operated in a transmissive mode this may, in embodiments, imply that at one or more wavelengths the part of the radiation that is transmitted may be larger than the part of the radiation that is reflected or absorbed. Herein, when an element is indicated to be operated in a reflective mode this may in embodiments imply that at one or more wavelengths the part of the radiation that is reflected may be larger than the part of the radiation that is transmitted or absorbed. Note that when the luminescent material would be damaged or deteriorated, device light will still not directly escape from the system, which may contribute to safety. The polarized light may for example have p-polarization or s-polarization, see also further below. In embodiments, the polarization of the device light may be controllable. In embodiments, the polarizing beam splitter may be configured d