Tunable beam combiner laser phosphor engine

Abstract

The present invention provides a light generation system (1000) comprising a first light generating device (110), a second light generating device (120), a light emitting material (200), a diffuser element (710), and an optical device (500); wherein: - the optical device (500) comprises: (a) a first beam splitter device (1500) disposed between the first light generating device (110) and the light emitting material (200); and (b) a second beam splitter device (2500) disposed between the second light generating device (120) and the diffuser element (710); - the first light generating device (110) is configured to generate first device light (111) having a first peak wavelength of λ1; the second light generating device (120) is configured to generate second device light (121) having a second peak wavelength of λ2; - wherein one of the beam splitter devices (1500, 2500) is configured to split the light emitting material light (201) and the light emitting material light (200) by the beam splitter device (500) into two beams. The received diffused second device light (711) is combined; - the optical device (500) includes: (c) a first lens assembly (1510) disposed between the first beam splitter assembly (1500) and the luminescent material (200); and (d) a second lens assembly (1520) disposed between the second beam splitter assembly (2500) and the diffuser element (710); - the optical device (500) includes: (e) a primary angle stretcher (TD11) disposed between the first light generating device (110) and the first lens assembly (1510); and (f) a secondary angle stretcher (TD12) disposed between the second light generating device (120) and the second lens assembly (1520); - the light generating system (1000) is configured to generate system light (1001) which includes one or more of the luminescent material light (201) and the diffused second device light (711).

Description

Technical Field

[0001] This invention relates to a light generating system. It also relates to a lighting device including the light generating system. Background Technology

[0002] Stage lighting engines based on laser phosphors are known in the art. For example, WO2022143318 describes a light-emitting device including a first light source, a second light source, a dichroic mirror, a wavelength conversion device, a first or second optical path adjustment device, and a first scattering optical system. The mixing effect of the emitted light can be improved by utilizing the first scattering optical system. All the light emitted by the first light source is used to excite the wavelength conversion device. Summary of the Invention

[0003] High-brightness light sources can be used in a variety of fields, including spotlights, stage lighting, headlamps, home and office lighting, and automotive lighting. For this purpose, laser-phosphor technology can be employed, where a laser provides the light, and a remote phosphor converts the laser into converted light. A relatively simple method for generating white light using lasers is to combine the laser with a phosphor to produce converted light. Laser-phosphor systems allow for the generation of high-brightness light and are therefore suitable for projection systems, including displays such as cinema projectors, as well as projectors for home, school, and office applications, automotive headlights, searchlights, stage lighting, architectural lighting, and special lighting applications. However, such light engines may only be able to produce a single color point defined by the light-emitting converter. Developing a product family offering different color points can be challenging, as it may require designing, validating, manufacturing, and stocking multiple unique components. In other cases, such as in RGB LCD-based projection systems, maximum brightness may be limited by the components used, the engine size may be large due to the large number of components, and the system cost may be high due to the numerous dedicated components. One method for combining pump and emitted light is to use a polarization beamsplitter to reflect a portion of the pump light to the emitting material and transmit a portion to a diffuser. However, in general, the diffused light appears to be largely depolarized, resulting in relatively high loss of the diffused blue light at the combiner where it is combined with the emitted light to form the white output light.

[0004] Therefore, one aspect of the present invention is to provide an alternative light-generating system, which preferably overcomes at least partially one or more of the aforementioned disadvantages. The object of the present invention may be to overcome or improve at least one disadvantage of the prior art, or to provide a useful alternative.

[0005] According to a first aspect of the present invention, a light generation system (“system”) is provided, comprising a first light generating device, a second light generating device, a light-emitting material, a diffuser element, and optical devices. Furthermore, the light generation system may also include a control system. Specifically, the optical devices may include a first beam splitter device. The first beam splitter device may be disposed between the first light generating device and the light-emitting material. Furthermore, the optical devices may also include a second beam splitter device. The second beam splitter device may be disposed between the second light generating device and the diffuser element. Furthermore, the first light generating device may be configured to generate first device light. The first device light may have a first peak wavelength λ1. In an embodiment, the first light generating device includes a first solid-state light source. Furthermore, the second light generating device may be configured to generate second device light. The second device light may have a second peak wavelength λ2. In an embodiment, the second light generating device includes a second solid-state light source. In an embodiment, the optical devices and the second light generating device may be configured such that the second device light incident on the second beam splitter device includes polarized light having p-polarization or s-polarization. Furthermore, in an embodiment, the light-emitting material may be configured to convert the first device light received by the light-emitting material into light-emitting material light. However, in embodiments, the diffuser element can be configured to diffuse at least a portion of the second device light received by the diffuser element, thereby providing diffused second device light. Specifically, the diffuser element can be configured to diffuse at least a portion of the second device light received by the diffuser element, thereby providing diffused second device light while maintaining at least a portion of the polarization of the second device light incident on the diffuser element. Furthermore, the luminescent material and / or the diffuser element, especially both, are configured to be in a reflection mode. In embodiments, one of the beamsplitter devices may also be configured to combine the luminescent material light and the diffused second device light received by the beamsplitter device. Furthermore, in embodiments, the optical device may also include a first lens device. The first lens device may be disposed between the first beamsplitter device and the luminescent material. Furthermore, the optical device may also include a second lens device. The second lens device may be disposed between the second beamsplitter device and the diffuser element. In embodiments, the first lens device may include a first primary lens (L11) and a second primary lens (L12). The first primary lens (L11) and the second primary lens (L12) may have a first inter-lens distance (d1). Furthermore, in an embodiment, the second lens assembly may include a first primary lens (L21) and a second primary lens (L22). The first primary lens (L21) and the second primary lens (L22) may have a second inter-lens distance (d2). In a specific embodiment, |1-d2 / d1|≥0.1. Additionally, the optics may also include a primary angle stretcher (TD11). The primary angle stretcher (TD11) may be disposed between the first light-generating device and the first lens assembly.Furthermore, the optical components may include a secondary angle stretcher (TD12). The secondary angle stretcher (TD12) may be disposed between the second light generating device and the second lens assembly. Additionally, in an embodiment, the primary angle stretcher (TD11) may be configured to diffuse the first device light received therefrom. Furthermore, in an embodiment, the secondary angle stretcher (TD12) may be configured to diffuse the second device light received therefrom. Specifically, the light generating system may be configured to generate system light, which includes one or more of luminescent material light and / or diffused second device light. Furthermore, the control system may be configured to control the spectral power distribution of the system light.Therefore, in an embodiment, the present invention provides a light generation system comprising a first light generating device, a second light generating device, a light-emitting material, a diffuser element, an optical device, and a control system; wherein: (A) the optical device comprises: (a) a first beam splitter device disposed between the first light generating device and the light-emitting material; and (b) a second beam splitter device disposed between the second light generating device and the diffuser element; (B) the first light generating device is configured to generate first device light having a first peak wavelength λ1; wherein the first light generating device comprises a first solid-state light source; (C) the second light generating device is configured to generate second device light having a second peak wavelength λ2; wherein the second light generating device... The device includes a second solid-state light source; (D) optical components and a second light-generating device are configured such that the second device light incident on the second beamsplitter includes polarized light having p-polarization or s-polarization; (E) a light-emitting material is configured to convert the first device light received therefrom into light-emitting material light; a diffuser element is configured to diffuse at least a portion of the second device light received therefrom, thereby providing diffused second device light while maintaining at least a portion of the polarization of the second device light incident on the diffuser element; the light-emitting material and the diffuser element are configured in a reflection mode; (F) wherein one of the beamsplitter devices is configured to combine the light-emitting material light and the diffused second device light received by the beamsplitter device. (G) The optical device includes: (c) a first lens assembly disposed between the first beam splitter assembly and the light-emitting material, and (d) a second lens assembly disposed between the second beam splitter assembly and the diffuser element; (H) the first lens assembly includes a first primary lens (L11) and a second primary lens (L12), wherein the first primary lens (L11) and the second primary lens (L12) have a first inter-lens distance (d1); (I) the second lens assembly includes a first primary lens (L21) and a second primary lens (L22), wherein the first primary lens (L21) and the second primary lens (L22) have a second inter-lens distance (d2); wherein |1-d2 / d1 |≥0.1; (J) The optical device further includes: (e) a primary angle stretcher (TD11) disposed between the first light generating device and the first lens assembly, and (f) a secondary angle stretcher (TD12) disposed between the second light generating device and the second lens assembly; (K) the primary angle stretcher (TD11) is configured to diffuse the first device light received therefrom; the secondary angle stretcher (TD12) is configured to diffuse the second device light received therefrom; and (L) the light generating system is configured to generate system light, the system light including one or more of luminescent material light and / or diffused second device light; and the control system is configured to control the spectral power distribution of the system light.

[0006] This invention provides a light engine architecture comprising two different types of optical elements / functions. This enables significantly better color uniformity in a high-brightness, high-throughput laser-phosphor engine than observed from commercially available devices with only a single diffuser added, while remaining highly efficient. Furthermore, the system can provide light with controllable color and / or correlated color temperature. Additionally, the system can be relatively simple.

[0007] As described above, the light generating system may specifically include a first light generating device and a second light generating device. However, the light generating system may also include a third light generating device (see below).

[0008] Each light-generating device may include a solid-state light source. In embodiments, the solid-state light source may be selected from laser diodes, multi-junction light-emitting diodes, superluminescent diodes, and diode arrays (especially laser diode arrays). Therefore, the first solid-state light source and the second solid-state light source (and optionally a third solid-state light source) may be selected from the group consisting of laser diodes, multi-junction light-emitting diodes, superluminescent diodes, and diode arrays. The diode array may include a laser group comprising an array of multiple laser chips, a superluminescent diode array, or a multi-junction light-emitting diode array, etc. Each light source may be configured to generate light source light, such as diode laser light, superluminescent diode light, multi-junction light-emitting diode light, etc. Alternatively or additionally, the solid-state light source may include a fiber-coupled solid-state diode laser.

[0009] A light generating device can be configured to generate device light, which includes the light described above. As mentioned above, a first light generating device can be configured to generate first device light, which in particular may include one or more light sources, such as diode laser light, superluminescent diode light, multijunction light-emitting diode light, etc. Similarly, a second light generating device can be configured to generate second device light, which in particular may include one or more light sources, such as diode laser light, superluminescent diode light, multijunction light-emitting diode light, etc. Furthermore, assuming the existence of another (e.g., a third) light generating device, the other (e.g., a third) light generating device can be configured to generate another (e.g., a third) device light, which in particular may include one or more light sources, such as diode laser light, superluminescent diode light, multijunction light-emitting diode light, etc. The light sources can all be of the same type, but are not required to be. For example, the first light generating device may include a solid-state laser, the second light generating device may include a solid-state laser (an optional third light generating device may include a solid-state laser).

[0010] Therefore, the first light-generating device may include a first solid-state light source. Furthermore, the first device light may have a first peak wavelength λ1. Specifically, the first peak wavelength may be selected from the blue wavelength range (see below). Furthermore, the second light-generating device may include a second solid-state light source. Furthermore, the second device light may have a second peak wavelength λ2. The luminescent material (see below) may be excited by UV light or blue light. In this document, the invention will be further explained in conjunction with blue light. Therefore, in embodiments, both the first device light and the second device light may include blue light. Specifically, both the first device light and the second device light are blue light. Therefore, in embodiments, the first peak wavelength λ1 and the second peak wavelength λ2 may each be selected from the wavelength range of 430-490 nm. Specifically, the second peak wavelength may be selected from the blue wavelength range. In embodiments, |λ1-λ2|≤10 nm, more specifically, |λ1-λ2|≤5 nm. Therefore, in certain embodiments, λ1=λ2 may be applicable. Specifically, when the first light-generating device and the second light-generating device can be selected from the same sub-range, the same spectral power distribution can be obtained. Therefore, the peak wavelengths can be substantially the same. However, in other embodiments, 10nm < |λ1-λ2| ≤ 60nm, such as 15nm ≤ |λ1-λ2| ≤ 50nm.

[0011] However, the optional third device light (see below) may have a third peak wavelength λ3. Specifically, the third peak wavelength may be selected from the blue wavelength range. In embodiments, |λ1-λ3|≤10nm, more specifically, |λ1-λ3|≤5nm, and |λ2-λ3|≤10nm, more specifically, |λ2-λ3|≤5nm. When the third light generating device and one or more of the first and second light generating devices are selected from the same range, the same spectral power distribution can be obtained. Therefore, the peak wavelengths may be substantially the same. In other embodiments, one or more of the following may be applicable: (i) 10nm < |λ1-λ3|≤60nm, such as 15nm ≤ |λ1-λ3|≤50nm, and (ii) 10nm < |λ2-λ3|≤60nm, such as 15nm ≤ |λ2-λ3|≤50nm.

[0012] Furthermore, the light-generating system may include a luminescent material (see below). Specifically, the luminescent material may be configured to convert the first device light received therefrom into luminescent material light. Additionally, in embodiments, the spectral power of the luminescent material light may be located in one or more of the following spectral ranges: green, yellow, orange, and red. It should be noted that the term "luminescent material" may also refer to a variety of different luminescent materials.

[0013] However, this light-generating system includes optical devices. The term "optical device" can specifically refer to one or more optical devices. Therefore, the terms "optical device" and "optical element" can refer to the same object. Optical devices can include one or more mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffraction elements, gratings, dichroic mirrors, arrays of one or more of the above, etc. Alternatively or additionally, the term "optical device" can also refer to holographic elements or mixing rods. In embodiments, optical devices can include one or more of beam expander optics and zoom lens optics. Examples of optical devices are given above. In embodiments, optical devices can include integrators, such as "Köhler integrators" (or "Köhler integrators"). The optical devices included in this light-generating system can include multiple optical elements, such as lenses and mirrors. Specific optical elements will be described in more detail herein.

[0014] The optical system may, in particular, include a first beamsplitter device. Specifically, the first beamsplitter device may be configured to: (i) receive light from a first device and direct it to a light-emitting material; and (ii) receive light from the light-emitting material and direct it to other locations in the system, such as a light exit point, optionally using other optical elements. Specifically, the first beamsplitter device may "split" the first device light and the light-emitting material light, wherein the first device light is transmitted through the first beamsplitter device while the light-emitting material is reflected by the first beamsplitter device; or the first device light is reflected by the first beamsplitter device while the light-emitting material light is transmitted through the first beamsplitter device. In a specific embodiment, the first beamsplitter device includes a dichroic beamsplitter (or a dichroic beam combiner). Furthermore, in an embodiment, the optical axis of the first device may be incident along a first direction, while the optical axis of the light-emitting material emanating from the first beamsplitter device may be along a second direction, which may be perpendicular to the first direction. Specifically, the first beamsplitter device may be disposed between the first light-generating device and the light-emitting material. The phrase "the first beam splitter device may be configured between the first light generating device and the light-emitting material" specifically indicates that the light from the first device can reach the light-emitting material through optical devices, including at least through the first beam splitter device (reflection or transmission). Specifically, the light-emitting material is configured in a reflection mode, but this document does not exclude a transmission mode.

[0015] Examples of such dichroic beam splitters include short-pass cutoff dichroic plates or long-pass cutoff dichroic plates. In a specific embodiment, the first dichroic beam splitter is designed for a 45° incident angle of the (first) device light.

[0016] The optical device may, in particular, include a second beamsplitter device. Specifically, the second beamsplitter device may be configured to: (i) receive second device light and guide it to a diffuser element; (ii) receive diffused second device light and guide it to other locations in the system, such as a light exit, and optionally use other optical devices. Specifically, the second beamsplitter device may “split” the second device light and the diffused second device light, wherein the second device light is transmitted by the second beamsplitter device and the diffused second device light is reflected by the second beamsplitter device; or the second device light is reflected by the second beamsplitter device and the diffused second device light is transmitted by the second beamsplitter device. In a particular embodiment, the second beamsplitter device includes a polarization beamsplitter (or polarization combiner). Furthermore, in an embodiment, the incident optical axis of the second device light may be incident along a first direction, while the optical axis of the diffused second device light escaping from the second beamsplitter device may be along a second direction, which may be perpendicular to the first direction. Specifically, the second beamsplitter device may be disposed between the second light generating device and the diffuser element. The phrase “the second beam splitter device can be configured between the second light generating device and the diffuser element” specifically indicates that the light from the second device can reach the diffuser element through the optical device, including at least via the second beam splitter device (reflection or transmission).

[0017] In the embodiments, the first beam splitter device and the second beam splitter device are physically separate optical elements. However, this document does not preclude the use of integrated optical devices that simultaneously possess the functions of the first beam splitter device and the second beam splitter device.

[0018] Therefore, in specific embodiments, the light generating system may further include a dichroic element configured to transmit or reflect light, and configured to reflect or transmit light from a luminescent material. The dichroic element may be an embodiment of a color-separating element, such as that described in US7070300 (the contents of which are incorporated herein by reference). Specifically, the color-separating element may be selected from the group consisting of dichroic mirrors, dichroic cubes, and diffractive optics. Optionally, the color-separating element may be provided using a hologram. Specifically, the dichroic element may be a dichroic mirror or a reflector.

[0019] Therefore, in a light generation system including a light source (e.g., a light source including a solid-state light source), the light source emits light having a first wavelength range along a first optical path, and a wavelength conversion element can be disposed in the first optical path. In embodiments, the wavelength conversion element can be physically separated from the light source. Furthermore, the wavelength conversion element can be configured to convert at least a portion of the light having the first wavelength range into light having a second wavelength range along a second optical path. Specifically, in embodiments, a color separation element, particularly a dichroic element, can be disposed between the light source and the wavelength conversion element. In embodiments, the color separation element can be configured to block almost all light having the second wavelength range from incident on the light source. Therefore, in embodiments, the color separation element can be configured to: (a) transmit at least a portion of the light having the first wavelength range and reflect at least a portion of the light having the second wavelength range, or (b) reflect at least a portion of the light having the first wavelength range and transmit at least a portion of the light having the second wavelength range.

[0020] Therefore, for a dichroic beam splitter, the following can be applied: for a first wavelength range, its average wavelength transmittance can be higher than that of the second wavelength range, for example, at least 10%, such as at least 20%, or even at least 30%. Similarly, for a first wavelength range, its average wavelength reflectance can be lower than that of the second wavelength range, for example, at least 10%, such as at least 20%, or even at least 30%. Specifically, in embodiments, the dichroic beam splitter can be configured to direct at least 60% of the light in the first wavelength range in a first direction and at least 60% of the light in the second wavelength range in a second direction, wherein, in embodiments, the two directions can have an angle between them selected from the range of 45° to 135°, for example, about 90°. The percentage of light can refer to (e.g., in watts) spectral power.

[0021] Therefore, for a polarization beamsplitter, the following can be applied: for the first polarization, its transmittance can be higher than that of the second polarization, for example, at least 10%, at least 20%, or even at least 30%. Similarly, for the first polarized light, its reflectance can be lower than that of the second polarization, for example, at least 10%, at least 20%, or even at least 30%. Specifically, in an embodiment, a dichroic beamsplitter can be configured to direct at least 60% of the first polarized light in a first direction and at least 60% of the second polarized light in a second direction, wherein, in an embodiment, the two directions can have a mutual angle selected from the range of 45° to 135°, for example, about 90°. The percentage of light can refer to (e.g., in watts) spectral power. Specifically, the first and second polarizations can include linear polarizations, such as those selected from s-polarization and p-polarization. Optionally, the first and second polarizations can also be selected from different elliptically polarized light. In an embodiment, the polarization beamsplitter described herein can be selected from a reflective polarization beamsplitter (reflective polarizer).

[0022] As described above, a polarization beamsplitter (or "first polarization beamsplitter") can be applied to the second beamsplitter device. This also means that the second device radiation received by the second beamsplitter device is polarized light. This can be achieved in one or more ways: (i) using a second light-generating device that produces polarized light, such as a solid-state laser; (ii) using polarization optics to provide the desired polarization to the second device light. Specifically, the polarization can be selected from s-polarization and p-polarization. Thus, the optics and the second light-generating device can be configured such that the second device light incident on the second beamsplitter device comprises polarized light having p-polarization or s-polarization.

[0023] Examples of such polarization beamsplitters include thin-film polarization beamsplitter plates, polarization beamsplitter cubes, etc., which reflect s-polarized light and transmit p-polarized light relative to the incident surface onto the beamsplitter. Furthermore, polarization beamsplitter plates that partially transmit and partially reflect orthogonally polarized light can also be used, for example, having a specific reflection / transmission splitting ratio for a particular polarization. In a specific embodiment, the polarization beamsplitter is designed for (second) device light to be incident at a 45° angle.

[0024] Returning to the diffuser element, the luminescent material light generated by converting at least a portion of the first device light can, by definition, be diffuse light. However, the (second) device light, which is mixed with the luminescent material light for color purposes (e.g., color tuning), is not necessarily diffuse light, or at least has a low degree of diffuseness, if no measures are taken. Therefore, light generation systems can, in particular, include diffuser elements. Thus, the diffuser element can be configured to diffuse at least a portion of the second device light received therefrom, thereby providing diffused second device light.

[0025] Since the second beam splitter device can be used to separate different polarizations, ideally, the diffused second device light is also polarized. Therefore, the diffuser element can be configured to diffuse at least a portion of the second device light received therefrom, thereby providing diffused second device light (see below) while maintaining at least a portion of the polarization of the second device light incident on the diffuser element.

[0026] Specifically, the diffuser element is configured to be in reflective mode. More specifically, both the luminescent material and the diffuser element are configured to be in reflective mode.

[0027] When luminescent material light and diffused second device light are generated simultaneously, ideally they can be combined into a single beam. For this purpose, a beam combiner can be applied. Specifically, one of the beam splitters can (also) be configured to combine the luminescent material light and diffused second device light received therefrom. Thus, in one embodiment, the first beam splitter can be configured to receive light from the second beam splitter and can also function as a beam combiner; in other embodiments, the second beam splitter can be configured to receive light from the first beam splitter and can also function as a beam combiner. The beam combiner can receive the luminescent material light and diffused second device light in orthogonal directions, transmit one of the luminescent material light and diffused second device light, and reflect the other of the luminescent material light and diffused second device light, thereby combining them. Since the second device light mixed in with the luminescent material light is diffuse, the (diffuse) second device light and the luminescent material light can be uniformly distributed in the beam comprising both.

[0028] Furthermore, the optical system may include: (c) a first lens assembly disposed between the first beam splitter assembly and the luminescent material; and (d) a second lens assembly disposed between the second beam splitter assembly and the diffuser element. The first lens assembly may be configured to: (i) provide a desired first device light spot on the luminescent material; and (ii) collect luminescent material light. Therefore, in an embodiment, the first lens assembly may be configured to focus the first device light onto the luminescent material and collect the luminescent material light emitted from the luminescent material. Similarly, the second lens assembly may be configured to: (i) provide a desired second device light spot on the diffuser element; and (ii) collect diffused second device light. Therefore, in an embodiment, the second lens assembly may be configured to focus the second device light onto the diffuser element and collect the diffused second device light emitted from the diffuser element.

[0029] In one embodiment, the first lens device may include two lenses. In other embodiments, the first lens device may include three lenses; however, the use of more lenses is not excluded. Similarly, in one embodiment, the second lens device may include two lenses. In other embodiments, the second lens device may include three lenses; however, the use of more lenses is not excluded. However, in one embodiment, the first lens device and the second lens device may have the same number of lenses.

[0030] In an embodiment, the first lens device may include a first primary lens (L11) and a second primary lens (L12). Specifically, the first primary lens (L11) and the second primary lens (L12) may have a first inter-lens distance (d1). Similarly, the second lens device may include a first secondary lens (L21) and a second secondary lens (L22). Specifically, the first secondary lens (L21) and the second secondary lens (L22) may have a second inter-lens distance (d2). The inter-lens distance may be the shortest distance between two adjacent lenses.

[0031] Especially in an embodiment, the inter-lens distances may be different. For example, this may allow a larger light spot to be provided on the diffuser element than on the luminescent material. In a specific embodiment, |1 - d2 / d1| ≥ 0.1 (where applicable). Thus, the first primary lens (L11) and the second primary lens (L12) may be configured to have a non-zero distance (from each other), such as at least 1 mm, at least 5 mm, such as at least 10 mm, such as at least 15 mm, or even at least 30 mm. Similarly, the first secondary lens (L21) and the second secondary lens (L22) may also be configured to have a non-zero distance (from each other), such as at least 5 mm, such as at least 10 mm, such as at least 15 mm, or even at least 30 mm.

[0032] In an embodiment, d1 > d2; in other embodiments, d1 < d2. Especially in an embodiment, d2 < d1. Additionally, in an embodiment, d2 / d1 ≤ 0.9. However, embodiments where d1 = d2 are also contemplated herein. In an embodiment, for two substantially identical lens devices and x1 = x2, making the two inter-lens distances unequal can provide a way to correct for different reflections of the reflective diffuser or the luminescent material. In these embodiments, d2 < d1 can be particularly applied because then d1 can be selected to focus the luminescent material (the smallest light spot), and then a smaller d2 can be selected to enlarge the light spot on the reflective diffuser while also limiting the losses caused by the reduced collection efficiency due to the larger inter-lens distance. In other embodiments, the lens devices may not be exactly the same, and thus x1 and x2 may not be the same either. In these embodiments, for example, d2 > d1 can be selected.

[0033] For example, if three lenses are selected, both lens devices can be composed of three lenses. At this time, there can be three types of lenses: L1, L2, and L3. This can mean that in their respective lens devices, the distances between the first lens and the second lens are d11 and d12 respectively, and the distances between the second lens and the third lens are d21 and d22 respectively. In such an embodiment, for example, the condition d21 < d11 or d22 < d12 may apply.

[0034] Furthermore, for example, to homogenize the light from the luminescent material and the diffused light from the second device, an angle stretcher can be applied upstream of the optical element used to combine the light from the luminescent material and the diffused light from the second device. Therefore, in an embodiment, the optical element may (f) include: (e) a primary angle stretcher (TD11) disposed between the first light-generating device and the first lens assembly, and / or (f) a secondary angle stretcher (TD12) disposed between the second light-generating device and the second lens assembly. Specifically, the primary angle stretcher (TD11) may be configured to diffuse the first device light received therefrom. Furthermore, specifically, the secondary angle stretcher (TD12) may be configured to diffuse the second device light received therefrom. This also contributes to improving the homogenization of the system light (see below).

[0035] Please note that the diffuser element can be configured in a reflective mode, while the primary and secondary angle stretchers can be configured in a transmissive mode.

[0036] The primary and secondary angle broadeners can, in particular, be flat-top diffusers. Furthermore, their diffusion angles (defined by the full width at half maximum (FWHM)) can be relatively small, for example, selected from the range of 0.5° to 20° respectively, and more specifically, from the range of 1° to 15° respectively. Specifically, the value of the diffusion angle can refer to the average diffusion angle (since diffusion can be angle-dependent). The average diffusion angle can be defined as the FWHM angle of the intensity-weighted rotational integral angle diffusion distribution of an incident pencil beam at a specific wavelength when incident perpendicularly (at an angle of zero). In this paper, the pencil beam can be a narrow beam with a small divergence angle, for example, less than 0.5°.

[0037] The primary angle stretcher (TD11) may have a first diffusion angle θ1, defined by a full width at half maximum (FWHM), which is particularly selectable from the range of 1-15°, and more particularly from the range of 1-10°. Furthermore, the secondary angle stretcher (TD12) may have a second diffusion angle θ2, defined by a full width at half maximum (FWHM), which is particularly selectable from the range of 1-15°, and more particularly from the range of 1-10°. Furthermore, since it may be necessary to ensure that the diffusion of light from the second device is at least equal, or particularly greater, in embodiments, θ2 / θ1 ≥ 1, for example, θ2 / θ1 > 1. Furthermore, in embodiments, θ2 / θ1 ≥ 1.1. Furthermore, in embodiments, θ2 / θ1 ≤ 2.

[0038] Specifically, a master-level angle stretcher (TD11) can be configured in the optical path between the first light-generating device and the light-emitting material. To diffuse the light from the first device (rather than further diffusing the light from the light-emitting material), the master-level angle stretcher (TD11) can be configured between the first light-generating device and the first beam splitter device (e.g., it may not be configured between the first beam splitter device and the light-emitting material, although such embodiments are not excluded herein). Similarly, a second angle stretcher (TD12) can be configured between the second light-generating device and the second beam splitter device.

[0039] Specifically, the light generation system is configured to generate system light, which includes one or more of luminescent material light and / or diffused second device light. Whether the system light includes luminescent material light and diffused second device light can depend on the control of the light generating devices. Assuming only a first light generating device and a second light generating device are present, the system light may include only luminescent material light when only the first light generating device is operational. Similarly, when only the second light generating device is operational, the system light may include only diffused second device light. In this way, the spectral power distribution of the system light can be controlled. Therefore, the light generation system may also include a control system. Specifically, the control system can be configured to control the spectral power distribution of the system light. For example, in an embodiment, the control system can control the color rendering index and / or correlated color temperature of the system light. Furthermore, the control system can control the spectral power distribution of the system light by controlling the first light generating device, the second light generating device, and optional other light generating devices (e.g., an optional third light generating device). Further descriptions of the control options for the spectral power distribution will follow in other parts of this document. In an embodiment, the control system can also control the radiative flux of system light by controlling the first light generating device, the second light generating device, and optional other light generating devices (such as an optional third light generating device).

[0040] In one embodiment, the first primary lens (L11) and the first secondary lens (L21) may be substantially identical in material, size, and effective focal length. However, this is not mandatory. Alternatively or additionally, in another embodiment, the second primary lens (L12) and the second secondary lens (L22) may be substantially identical in material, size, and effective focal length. However, this is also not mandatory. Substantially identical first and second primary lenses, and / or substantially identical second and secondary lenses, can provide a relatively simple structure. However, this is also not mandatory.

[0041] Specifically, in an embodiment, the angular spread of the light rays exiting from the second primary lens (L12) towards the light-emitting material can be greater than the angular spread of the light rays exiting from the first primary lens (L11) towards the light-emitting material (similarly, the applicable angular spread of the incident light rays of the light-emitting material along the direction away from the light-emitting material). Similarly, especially in an embodiment, the angular spread of the light rays exiting from the second secondary lens (L22) towards the diffuser element can be greater than the angular spread of the light rays exiting from the first secondary lens (L21) towards the diffuser element (similarly, the applicable angular spread of the incident light rays of the diffused second device light along the direction away from the diffuser element). Therefore, in an embodiment, the first primary lens (L11) has a first primary optical power P11, the second primary lens (L12) has a second primary optical power P12, the first secondary lens (L21) has a first secondary optical power P21, and the second secondary lens (L22) has a second secondary optical power P22, where in a specific embodiment, P12 > P11 and / or P22 > P21. In other specific embodiments, P12 / P11 ≥ 1.1 and / or P22 / P21 ≥ 1.1. Additionally, in an embodiment, for example, in an embodiment P12 / P11 ≤ 5, such as at most 3 in an embodiment, and / or P22 / P21 ≤ 5, such as at most 3 in an embodiment. Specifically, the optical power can refer to the degree to which an optical element such as a lens, a mirror, or other optical elements converges or diverges light rays. It can especially be equal to the reciprocal of the focal length of the optical element: P = 1 / f.

[0042] In addition, the first primary lens (L11) can have a first primary numerical aperture N11, the second primary lens (L12) can have a second primary numerical aperture N12, the first secondary lens (L21) can have a first secondary numerical aperture N21, and the second secondary lens (L22) can have a second secondary numerical aperture N22. In an embodiment, especially when the first primary lens (L11) and the first secondary lens (L21) are substantially the same, and the second primary lens (L12) and the second secondary lens (L22) are substantially the same, one or more of the following can apply: (i) N12 > N11; (ii) N22 > N21. Additionally, in a specific embodiment, 0.9 ≤ N11 / N21 ≤ 1.1 and 0.9 ≤ N21 / N22 ≤ 1.1. However, other values may also hold. For example, N12 < N11 and / or N22 < N21 are not excluded here and can be selected according to the type of lens chosen.

[0043] Furthermore, the luminescent material and the first lens assembly may have a first shortest distance (x1), and the diffuser element and the second lens assembly may have a second shortest distance (x2). Specifically, x1 is the shortest distance between the second primary lens and the surface of the luminescent material, and x2 is the shortest distance between the second primary lens L22 and the surface of the reflective diffuser. In an embodiment, x2 = x1. However, in other embodiments, x2 ≠ x1. In a specific embodiment, x2 / x1 ≤ 0.9 or x2 / x1 ≥ 1.1. However, in an embodiment, 0.2 ≤ x2 / x1 ≤ 5.

[0044] As described above, the second beamsplitter device can distinguish light based on polarization. Therefore, in these embodiments, it is ideal that the second device light and the diffused second device light have different polarizations. This can be well achieved when a polarization-changing element is arranged between the second beamsplitter device and the diffuser element, in the optical path of the second device light (and the diffused second device light). Specifically, such a polarization-changing element may include a λ / 4 waveplate. Thus, in embodiments, the system may include a polarization-changing element comprising a λ / 4 waveplate, wherein the polarization-changing element is arranged between the second beamsplitter device and the second lens device. Specifically, the λ / 4 waveplate is an λ / 4 waveplate optimized for a wavelength range including the second peak wavelength.

[0045] Specifically, the polarization-changing element is configured to convert s-polarized or p-polarized light into circularly polarized light. A diffuser element can change the direction of polarized light, but circularly polarized light can remain substantially circularly polarized. At least a portion of the circularly polarized diffuse light propagates from the diffuser element to the polarization-changing element and is then converted into (diffuse) s-polarized light and / or (diffuse) p-polarized light, which can also propagate to one of the beamsplitter devices, particularly (at least) the second beamsplitter device. Therefore, in embodiments, the polarization-changing element may include a λ / 4 waveplate. By configuring the polarization-changing element between the second beamsplitter device and the second lens device, p-polarized light can be converted into diffuse s-polarized light, and vice versa.

[0046] Specifically, a polarization-changing element can be an element that produces a 90° phase shift between the two orthogonally linearly polarized components (s and p) of light. The most common method is to use birefringent materials (birefringent rotators), such as quarter-wave plates (1 / 4λ waveplates). Another method utilizes the Faraday effect, in which case the phase shift is caused by an applied magnetic field (Faraday rotator). Typically, a retarder can provide a defined phase shift between the polarization components projected along the fast and slow axes of the birefringent material. In our example, a λ / 4 phase shift might be desired. The same effect can also be achieved using multi-stage waveplates (n + λ / 4 phase shift), where n is an integer. However, Fresnel rhombus retarders can also be used to produce a λ / 4 phase shift. Faraday rotators are commonly used to rotate the direction of linearly polarized light. Combining a 45° Faraday rotator with an end reflector can form a Faraday mirror, capable of isolating the incident and back-propagating beams according to their polarization direction.

[0047] Essentially, the undiffused second device light can include, for example, light with a first linear polarization, which, upon passing through a polarization-changing element (e.g., a quarter-wave plate), is transformed into elliptically polarized light with a first rotation direction, such as right-handed circularly polarized light. A diffuser element can convert this elliptically polarized undiffused light with the first rotation direction into elliptically polarized diffuse light with a second rotation direction opposite to the first rotation direction, i.e., for example, left-handed circularly polarized light (consistent with the example above). This elliptically polarized diffuse light with the second rotation direction, upon passing again through a polarization-changing element (e.g., a quarter-wave plate), is transformed into diffuse light including a second linear polarization. The first linear polarization differs from the second linear polarization, and both are selected from s-polarization and p-polarization. Therefore, in an embodiment, the undiffused second device light can, for example, include p-polarized light that, upon passing through a quarter-wave plate (QWP), is transformed into, for example, left-handed circularly polarized light, which is diffused by a reflective diffuser into right-handed circularly polarized light, which is then transformed into s-polarized light upon passing through the QWP again. Depending on the orientation of the QWP, the incident p-polarized light can also be alternatively converted into right-handed circularly polarized light by the QWP, and then the s-polarized light is converted into left-handed circularly polarized light.

[0048] Therefore, if the undiffused second device light comprises p-polarized light, then the diffused second device light may comprise s-polarized light. Similarly, if the undiffused second device light comprises s-polarized light, then the diffused second device light may comprise p-polarized light. Thus, the phrase “maintaining at least part of the polarization of the second device light incident on the diffuser element” and similar phrases particularly indicate that the second device light, after reflection at the diffuser element, still possesses elliptically polarized light, although its rotation may have changed from left-handed elliptically polarized light to right-handed elliptically polarized light, and vice versa.

[0049] In embodiments, a third light-generating device may be applied in addition to the first and second light-generating devices. The third light-generating device can be used to increase the maximum spectral power that can be received by the luminescent material or the maximum spectral power that can be received by the diffuser element. Furthermore, if desired, the third light-generating device can also allow for further color adjustment of the system light when the spectral power distribution of the third device light generated by the third light-generating device differs from the spectral power distribution of the light-generating device configured to pump the same object (selected from the luminescent material and the diffuser element). In the embodiments described below, the third light-generating device is also used to pump the luminescent material. However, the invention is not limited to such embodiments. If the third light-generating device is also used to pump the diffuser element, diffuse third device light is generated.

[0050] The third light-generating device is configured to generate a third device light with a peak wavelength of λ3. As described above, this third device light may include blue light (see above for details). The first and second device lights may be combined before reaching the luminescent material. For this purpose, a beam combiner (or "beam splitter") may be applied, which is configured to combine the two beams into a single beam. Such a beam combiner may be a polarization beam combiner (or polarization beam splitter) based on (orthogonal) incident light with different polarizations; or it may be a dichroic beam combiner (or dichroic beam splitter) based on (orthogonal) incident light with different spectral power distributions. In embodiments, the beam combiner may be selected from a dichroic beam combiner or a polarization beam combiner.

[0051] Therefore, in embodiments, the system may further include: (i) a third light-generating device, and (ii) another beam combiner. Specifically, the third device light includes polarized light with p-polarization or s-polarization, while the first device light includes polarized light with p-polarization or s-polarization; wherein the polarizations of the first device light and the third device light are different. Alternatively or additionally, the third device light and the first device light have different spectral power distributions, particularly with peak wavelengths differing by at least about 10 nm. Furthermore, in embodiments, an additional beam combiner (such as a second polarization beam combiner or a second dichroic beam combiner) may be configured upstream of the first beam splitter device and may be configured to combine the first device light and the third device light received by the additional beam combiner and guide the combined beam to the first beam splitter device. For example, in a specific embodiment, the light generation system may further include: (i) a third light generation device, and (ii) a (second) polarization combiner, wherein: (A) the third device light includes polarized light having p-polarization or s-polarization; (B) the first device light includes polarized light having p-polarization or s-polarization; the first device light and the third device light have different polarizations; and (C) the (second) polarization combiner may be disposed upstream of the first beam splitter device and may be configured to combine the first device light and the third device light received by the second polarization combiner and guide the combined beam to the first beam splitter device.

[0052] After generating the luminescent material light and the diffused second device light, it may be necessary to combine them so that, in the operating mode of the light generation system, when both the first and second light generating devices provide device light, the system light includes the luminescent material light and the diffused second device light. There are several solutions; for example, one of the beamsplitters can be configured as a beam combiner. It should be noted that a polarization beamsplitter can also function as a polarization beam combiner; similarly, a dichroic beamsplitter can also function as a dichroic beam combiner.

[0053] Therefore, in specific embodiments, the second beamsplitter device may include polarization beam splitting and dichroic beam combining functions. The former has been described above, while the latter indicates that the second beamsplitter device can also combine the luminescent material light received therefrom with the diffused second device light. For example, in an embodiment, the polarization function is used to separate the reflected diffused device light from the non-reflective diffused device light and combine the reflected diffused device light with the luminescent light; the dichroic function is embodied in the requirement that the element transmits luminescent light but reflects s-polarized (second) device light, thereby combining the luminescent light with the s-polarized (second) device light. Specifically, in an embodiment, the second beamsplitter device may be configured to: (a) guide the second device light to the first beamsplitter device or diffuser element according to the polarization of the second device light; and (b) combine the diffused second device light received by the second beamsplitter device with the luminescent material light.

[0054] When the light generation system also includes a polarization control element, finer control can be achieved. This polarization control element can be configured to control the polarization of the second device light received by the second beamsplitter. In one embodiment, the polarization control element may include a birefringence rotator, wherein the polarization control element is disposed between the second light generation device and the second beamsplitter. Instead of or in addition to a birefringence rotator, a waveplate or polarization delay unit may also be used. In other embodiments, the polarization control element may include an actuator configured to control the second light generation device to rotate about the optical axis of its (the second device light's) output beam.

[0055] In embodiments, the polarization control element may include a rotatable birefringent rotator. More specifically, the (rotatable) birefringent rotator includes a λ / 2 waveplate. However, other phase-shift induction elements for two linearly orthogonal polarization components capable of altering the ratio of transmitted to reflected light may also be applied. Using a half-waveplate, 0-100% of s-polarized light can be converted to p-polarized light; using a quarter-waveplate, the conversion ratio may be only 0-50%; using a 3 / 8 waveplate, the conversion ratio is 0-75%; and using an 1 / 8 waveplate, the conversion ratio is 0-25%. Thus, a half-waveplate offers complete flexibility (and is unaffected by the actual polarization direction of the light source), while other options may have more limitations, both in terms of the proportion of light that can be converted to the desired polarization component and in terms of the orientation of the light source's polarization direction.

[0056] The polarization of the light from the second device can be controlled using a polarization control element. For example, using a (rotatable) λ / 2 delay unit (see below), the polarization between complete s-polarization and complete p-polarization can be selected in an embodiment. Therefore, in an embodiment, the polarization control element can be configured, in particular, to control the polarization of the light from the second device. In an embodiment, the polarization control element can be configured, in particular, to control the degree of polarization of the polarized light.

[0057] Specifically, in an embodiment, the degree of polarization can be defined as the percentage of p-polarized or s-polarized light relative to the sum of s-polarized and p-polarized light. To determine these percentages, the angular brightness of the second device light with s-polarization and the angular brightness of the second device light with p-polarization can be applied. For example, the second device light located downstream of the polarization control element can have 20% s-polarization and 80% p-polarization. Regarding angular brightness, see, for example, the paper “Towards apolarized light-emitting backlight: Micro-structured anisotropic layers” by Blom, S et al., DOI: 10.1889 / 1.1827869, *Journal of the Society for Information Display*, September 2002, pp. 209-213. In addition to angular brightness, luminance can also be applied.

[0058] However, the term "degree of polarization" is known in the art (generally). Specifically, in embodiments, the degree of polarization can be defined as the percentage of p-polarized light and / or s-polarized light relative to the sum of p-polarized light and s-polarized light. Measurements of the degree of polarization are known in the art and can be based on Stokes parameters.

[0059] The system may include an actuator configured to control a polarization control element. The control system may control the actuator to control the polarization control element.

[0060] The terms "upstream" and "downstream" refer to the arrangement of an object or feature relative to the direction of propagation of light emitted from a light-generating device (specifically, a light source). The second position in the light beam closer to the light-generating device is "upstream" relative to a first position within the light beam emitted from the light-generating device, while the third position in the light beam further away from the light-generating device is "downstream".

[0061] However, in other embodiments, the system may further include a three-stage angle broadener (TD13) configured between (i) the second beam splitter assembly and the second lens assembly. or (ii) Between the first and second beam splitter devices. This allows for further control of the beam width. The third-stage angle broadener can, in particular, be a flat-top diffuser. Furthermore, the diffusion angle defined by the full width at half maximum (FWHM) can be relatively small, for example, selected individually from a range of 0.5° to 20°, and more specifically, from a range of 1° to 15°. Specifically, the value of the diffusion angle can refer to the average diffusion angle (since diffusion can be angle-dependent) (see also above). In the embodiment, the third-stage angle broadener (TD13) has a third diffusion angle (θ3) selectable from a range of 1° to 15°, and more specifically, from a range of 1° to 10°.

[0062] Angle stretchers, such as primary angle stretchers, secondary angle stretchers, and tertiary angle stretchers, can be selected from the group consisting of transmissive diffusers, lens arrays, and compound eye lens array pairs, respectively. Therefore, in embodiments, reference TD can refer to a transmissive diffuser, but in other embodiments, it can refer to a lens array or a compound eye lens array pair. An angle stretcher can also be represented as an integrator. An angle stretcher is particularly useful for: (i) reducing hot spots projected onto diffuser elements (and similarly, luminescent materials) (potentially improving lifetime); and (ii) defining the angular range of light at the spot, which is the spatial range of light converted by the converging lens system onto the target plane (diffuser or luminescent material) (i.e., the defined spot size), for a desired irradiance distribution at that spot. The diffuser can therefore have the function of defining an initial spread of the emitted light, which is related to the final spread of the system light.

[0063] As mentioned above, whether the system light includes both luminescent material light and diffused second device light depends on the control method of the light generating device. Therefore, in a specific embodiment, when the light generating system is in operating mode, the system light includes both luminescent material light and diffused second device light. Furthermore, in a specific embodiment, the correlated color temperature of the system light can be selected from the range of 1500-12000K, for example, 1600-10000K. Alternatively or additionally, in a specific embodiment, the color rendering index of the system light can be at least 65, for example, at least about 70.

[0064] The control system can be configured to control a first light-generating device and a second light-generating device. When a third light-generating device is present, the control system can be configured to control the first, second, and third light-generating devices. Specifically, such control in embodiments may include controlling spectral power (i.e., including up-dimming and down-dimming). Furthermore, the control system may control optional polarization control elements. In these ways, the spectral power distribution of the system light can be controlled. However, if a rotatable element (for supporting one or more of the luminescent material and diffuser elements) is present (see below), the control system may also be configured to control the rotation (speed) of the rotatable element (in the operating mode of the light-generating system).

[0065] Therefore, in embodiments, the rotatable element includes one or more of a luminescent material and / or a diffuser element. This allows for the distribution of device light over a larger cooling area, thereby allowing for better heat dissipation. Phosphor wheels are known in the art. Therefore, the rotatable element may include a phosphor wheel having annularly distributed luminescent material and / or annularly distributed diffuser elements. The rotatable element may support the luminescent material.

[0066] In one aspect, the present invention also provides a light generating system, the system comprising a first light generating device, a second light generating device, a light-emitting material, a diffuser element, optical devices, and a control system; wherein:

[0067] - The optical device includes: (a) a first beam splitter device disposed between a first light generating device and a light emitting material; and (b) a second beam splitter device disposed between a second light generating device and a diffuser element;

[0068] - A first light generating device is configured to generate first device light having a first peak wavelength λ1; wherein the first light generating device includes a first solid-state light source; a second light generating device is configured to generate second device light having a second peak wavelength λ2; wherein the second light generating device includes a second solid-state light source;

[0069] - The luminescent material is configured to convert first device light received by the luminescent material into luminescent material light; the diffuser element is configured to diffuse at least a portion of the second device light received by the diffuser element, thereby providing diffused second device light while maintaining at least a portion of the polarization of the second device light incident on the diffuser element; the luminescent material and the diffuser element are configured to be in a reflection mode;

[0070] - One of the beam splitter devices is also configured to combine the light from the luminescent material received by the beam splitter device with the diffused light from the second device;

[0071] - The optical device further includes: (c) a first lens assembly disposed between the first beam splitter assembly and the light-emitting material; and (d) a second lens assembly disposed between the second beam splitter assembly and the diffuser element;

[0072] The first lens assembly includes a first primary lens (L11) and a second primary lens (L12), wherein the first primary lens (L11) and the second primary lens (L12) have a first inter-lens distance (d1); the second lens assembly includes a first primary lens (L21) and a second primary lens (L22), wherein the first primary lens (L21) and the second primary lens (L22) have a second inter-lens distance (d2).

[0073] - The optical device further includes: (e) a primary angle stretcher (TD11) disposed between the first light generating device and the first lens assembly; and (f) a secondary angle stretcher (TD12) disposed between the second light generating device and the second lens assembly;

[0074] - The primary angle stretcher (TD11) is configured to diffuse the first device light received by the primary angle stretcher (TD11); the secondary angle stretcher (TD12) is configured to diffuse the second device light received by the secondary angle stretcher (TD12);

[0075] - The primary angle stretcher (TD11) has a first diffusion angle θ1, which is defined by half-height full width and is selected from the range of 1-15° (especially from the range of 1-10°); wherein the secondary angle stretcher (TD12) has a second diffusion angle θ2, which is defined by half-height full width and is selected from the range of 1-15° (especially from the range of 1-10°).

[0076] - The luminescent material has a first shortest distance (x1) with the first lens device, and the diffuser element has a second shortest distance (x2) with the second lens device.

[0077] - The light generation system is configured to generate system light, which includes one or more of luminescent material light and / or diffused second device light; and the control system is configured to control the spectral power distribution of the system light; and

[0078] - One or more of the following apply: (i) |1-d2 / d1|≥0.1, (ii) θ2 / θ1≥1 (such as θ2 / θ1>1), and (iii) x2≠x1 (such as x2 / x1≤0.9).

[0079] Furthermore, as described above, in particular the optical device and the second light generating device are configured such that the second device light (in which it is incident on the second beam splitter device) comprises polarized light having p-polarization or s-polarization.

[0080] Some other embodiments will be described below.

[0081] The term "light source" can, in principle, refer to any light source known in the art. In a specific embodiment, the light source includes a solid-state LED light source (e.g., an LED or a laser diode (or "diode laser")). The term "light source" can also refer to multiple light sources, such as 2-2000 (solid-state) LED light sources. Therefore, the term "LED" can also refer to multiple LEDs.

[0082] Furthermore, in embodiments, the term "light source" may also refer to a so-called chip-on-board (COB) light source. The term "COB" specifically refers to an LED chip that exists as a semiconductor chip, neither packaged nor connected, but directly mounted on a substrate (e.g., a PCB). Therefore, multiple light-emitting semiconductor light sources can be configured on the same substrate. In embodiments, a COB combines multiple LED chips to form a single lighting module. The term "light source" may also refer to a chip-scale package (CSP). A CSP may include a single solid-state die with a layer comprising a light-emitting material. The term "light source" may also refer to a medium-power package. A medium-power package may include one or more solid-state dies. These dies may be covered by a layer comprising a light-emitting material. The die size may be equal to or less than 2 mm, such as, for example, in the range of 0.2-2 mm. Therefore, in embodiments, the light source includes a solid-state light source. Furthermore, in specific embodiments, the light source includes a chip-scale packaged LED. Herein, the term "light source" may also specifically refer to a small solid-state light source, such as a light source having a miniature or micro-sized design. For example, a light source may include one or more miniature LEDs and micro-LEDs. Specifically, in the embodiments, the light source includes a microLED or “microLED” or “µLED”. Hereinafter, “mini-size” or “miniLED” specifically refers to a solid-state light source whose dimensions (e.g., die size, particularly length and width) are selected from the range of 100µm to 1mm. Hereinafter, the term “µ-size” or “microLED” specifically refers to a solid-state light source having dimensions (e.g., die size).

[0083] The term "light source" can refer to semiconductor light-emitting devices, such as light-emitting diodes (LEDs), laser diodes, resonant cavity light-emitting diodes (RCLEDs), vertical cavity laser diodes (VCSELs), edge-emitting lasers (EELs), photonic crystal surface-emitting lasers (PCSELs), and vertical external cavity surface-emitting lasers (VECSELs). In specific embodiments, the light source includes solid-state light sources (e.g., LEDs or laser diodes). In an embodiment, the light source includes LEDs (light-emitting diodes). The term "light source" or "solid-state light source" can also refer to superluminescent diodes (SLEDs).

[0084] The term "LED" can also refer to multiple LEDs.

[0085] The term "light source" can also refer to multiple (substantially identical or different) light sources, such as 2-2000 solid-state light sources. In embodiments, a light source may include one or more micro-optical elements (microlens arrays) downstream of a single solid-state light source (e.g., an LED), or micro-optical elements downstream of multiple solid-state light sources (i.e., shared by multiple LEDs). In embodiments, a light source may include an LED with on-chip optics. In embodiments, a light source includes pixelated individual LEDs (with or without optics) (provided with on-chip beam control in embodiments).

[0086] The light source can be configured to generate light with an optical axis (O), beam shape, and spectral power distribution. In embodiments, the light source may include one or more wavelength bands having bandwidths known to the laser.

[0087] The term "light source" can refer to the light-generating element itself, such as a solid-state light source; it can also refer to the package of the light-generating element, such as a solid-state light source, and one or more of the elements that include luminescent material and (other) optical devices (such as lenses, collimators). A light-converting element ("converter element" or "converter") can include an element having luminescent material. For example, a solid-state light source itself, such as a blue LED, is a light source. A combination of a solid-state light source (as a light-generating element) and a light-converting element (optically coupled to the solid-state light source) (e.g., a blue LED and a light-converting element) can also be a light source (but can also be called a light-generating device). Therefore, a white LED is a light source (but can also be called, for example, a (white) light-generating device).

[0088] The term "light source" in this article may also refer to light sources including solid-state light sources, such as LEDs, laser diodes, or superluminescent diodes.

[0089] The term "light generating device" can be used to refer to light sources as well as other (optical devices), such as optical filters and / or beam shaping elements.

[0090] In embodiments, the phrase "different light sources" or "multiple different light sources" and similar phrases may refer to multiple solid-state light sources selected from at least two different tiers. Similarly, in embodiments, the phrase "identical light sources" or "multiple identical light sources" and similar phrases may refer to multiple solid-state light sources selected from the same tier.

[0091] The terms "solid-state light source" or "solid-state material light source" and similar terms particularly refer to semiconductor light sources, such as light-emitting diodes (LEDs), laser diodes, or superluminescent diodes. Specifically, in embodiments, the term "laser" may refer to a solid-state laser. In specific embodiments, the terms "laser" or "laser source" or similar terms refer to a laser diode (or diode laser). In embodiments, the terms "laser," "solid-state laser," or "solid-state material laser" may refer to one or more of the following: semiconductor laser diodes, such as GaN, InGaN, AlGaInP, AlGaAs, InGaAsP, lead salts, vertical-cavity surface-emitting lasers (VCSELs), quantum cascade lasers, hybrid silicon lasers, etc. In embodiments, laser light sources may be arranged as laser groups (see also above). In embodiments, laser groups may include heat sinks and / or optics, such as lenses for collimating lasers. Therefore, in embodiments, lasers in a laser group (or "laser array group") may share the same optics.

[0092] A laser source is configured to generate laser light (or "laser"). This light primarily consists of laser light. It may also include laser light from two or more (different or identical) laser sources. For example, laser light from two or more (different or identical) laser sources can be coupled into a light guide to provide a single beam of light comprising laser light from two or more (different or identical) laser sources. In a particular embodiment, this light is specifically collimated. In another embodiment, this light is specifically (collimated) laser light.

[0093] In embodiments, the laser source light may include one or more wavelength bands having a bandwidth known to the laser. In specific embodiments, these wavelength bands may be relatively sharp spectral lines, for example, with a full width at half maximum (FWHM) of less than 20 nm at RT, such as equal to or less than 10 nm. Therefore, the source light has a spectral power distribution (intensity on an energy scale as a function of wavelength), which may include one or more (narrow) wavelength bands.

[0094] The term "solid-state material laser" and similar terms may refer to solid-state lasers based on crystals or glasses doped with transition metal ions and / or lanthanide ions, or they may refer to fiber lasers, photonic crystal lasers, semiconductor lasers (such as, for example, vertical cavity surface-emitting lasers (VCSELs)).

[0095] The term "solid-state light source" and similar terms may in particular refer to semiconductor light sources, such as light-emitting diodes (LEDs), laser diodes, or superluminescent diodes.

[0096] The spectral power distributions may be different or the same. For example, the spectral power distributions of the first device light and the second device light may be different or the same. In a specific embodiment, the colors or color points of the first type of light and the second type of light may be different when their respective color points differ by at least 0.01 with respect to u' and / or at least 0.01 with respect to v', or even more specifically, when they differ by at least 0.02 with respect to u' and / or at least 0.02 with respect to v'. In a more specific embodiment, the respective color points of the first type of light and the second type of light differ by at least 0.03 with respect to u' and / or at least 0.03 with respect to v'. Here, u' and v' are the color coordinates of the light in the CIE 1976 UCS (Uniform Chromaticity Scale) diagram. The spectral power distributions of different light sources with a centroid wavelength difference of at least 10 nm (e.g., at least 20 nm, or even at least 30 nm) can be considered different spectral power distributions, e.g., different colors. Typically, the difference in centroid wavelength will not exceed about 400 nm, e.g., no more than 350 nm. In other specific embodiments, the colors or color points of the first and second types of light can be substantially the same when the respective color points of the first and second types of light differ by at most 0.03 with respect to u' and / or at most 0.03 with respect to v', or even more particularly when they differ by at most 0.02 with respect to u' and / or at most 0.02 with respect to v'. In a more specific embodiment, the respective color points of the first and second types of light differ by at most 0.01 with respect to u' and / or at most 0.01 with respect to v'. Here, u' and v' are the color coordinates of light in the CIE 1976 UCS (Uniform Chromaticity Scale) diagram. The color points represented by u' and v' specifically refer to the CIE 1976 color points (see ISO CIE 11664-5: Colorimetry - Part 5: CIE 1976 L). u v Color space and u', v' uniform chromaticity scale diagram).

[0097] Furthermore, the light-generating system includes a luminescent material. The term "luminescent material" specifically refers to a material capable of converting a first radiation (particularly one or more of UV radiation and / or blue light radiation) into a second radiation. Typically, the first and second radiations have different spectral power distributions. Therefore, in addition to the term "luminescent material," the terms "luminescent converter" or "converter" can also be used. Generally, the spectral power distribution wavelength of the second radiation is longer than that of the first radiation; this is a case of so-called downconversion. However, in specific embodiments, the second radiation has a spectral power distribution at a shorter wavelength than the first radiation; this is a case of so-called upconversion.

[0098] In embodiments, "luminescent material" can specifically refer to a material capable of converting radiation into visible light and / or infrared light. For example, in embodiments, the luminescent material is capable of converting one or more of UV radiation and / or blue light radiation into visible light. In specific embodiments, the luminescent material can also convert radiation into infrared radiation (IR). Therefore, when excited by radiation, the luminescent material emits radiation. Typically, the luminescent material is a down-converter, that is, radiation with shorter wavelengths is converted into radiation with longer wavelengths (λ). ex <λ em However, in specific embodiments, the luminescent material may include an up-converter luminescent material, that is, longer wavelength radiation is converted into shorter wavelength radiation (λ). ex >λ em ).

[0099] In embodiments, the term "luminescence" may refer to phosphorescence. In embodiments, the term "luminescence" may also refer to fluorescence. In addition to the term "luminescence," the term "emission" may also be used. Therefore, the terms "first radiation" and "second radiation" may refer to excitation radiation and emission (radiation), respectively. Similarly, in embodiments, the term "luminescent material" may refer to phosphorescence and / or fluorescence.

[0100] The term "luminescent material" can also refer to a variety of different luminescent materials. Examples of some possible luminescent materials are listed below. Therefore, in specific embodiments, the term "luminescent material" can also refer to a luminescent material composition. Furthermore, the term "phosphorus" may be used instead of "luminescent material." These terms are known to those skilled in the art.

[0101] In the embodiments, the luminescent material is selected from garnet and nitride, particularly garnet and nitride doped with trivalent cerium or divalent europium, respectively. The term "nitride" may also refer to oxynitride or nitrogen silicate, etc. Alternatively or additionally, the luminescent material may also be selected from silicates, particularly silicates doped with divalent europium.

[0102] In a specific embodiment, the luminescent material includes A3B5O. 12 Ce-type luminescent materials, wherein A in embodiments comprises one or more of Y, La, Gd, Tb, and Lu, particularly (at least) one or more of Y, Gd, Tb, and Lu, and B in embodiments comprises one or more of Al, Ga, In, and Sc. Specifically, A may comprise one or more of Y, Gd, and Lu, for example, particularly one or more of Y and Lu. Specifically, B may comprise one or more of Al and Ga, more specifically, at least Al, for example, almost entirely Al. Therefore, cerium-containing garnet materials are particularly suitable luminescent materials. Examples of garnet particularly include A3B5O. 12Garnets, wherein A comprises at least yttrium or lutetium, and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), praseodymium (Pr), or a combination of cerium and praseodymium; in particular, they may be doped with cerium. B may particularly comprise aluminum (Al); however, in addition to aluminum, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), particularly up to about 20% of B, more specifically up to about 10% of B (i.e., the B ions mainly consist of 90% or more in mole % of aluminum and 10% or less in mole % of one or more of gallium, scandium, and indium); B may particularly comprise up to about 10% of gallium. In another variant, B and O may be at least partly replaced by Si and N. Element A may particularly be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb), and lutetium (Lu). In addition, the content of Gd and / or Tb usually only accounts for about 20% of A. In a specific embodiment, the garnet luminescent material comprises , where x is greater than or equal to 0 and less than or equal to 1. The term ":Ce" means that part of the metal ions in the luminescent material (i.e., in the garnet: part of the "A" ions) are replaced by Ce. For example, in 's case, part of Y and / or Lu is replaced by Ce. This is known to those skilled in the art. The amount of Ce replacing A usually does not exceed 10%; generally, the concentration of Ce (relative to A) will be in the range of 0.1% to 4%, particularly in the range of 0.1% to 2%. Assuming the Ce content is 1% and the Y content is 10%, the complete chemical formula is . As known to those skilled in the art, Ce in the garnet is basically or only in the trivalent state.

[0103] In an embodiment, the luminescent material (therefore) comprises A3B5O 12 , where in a specific embodiment, at most 10% of B - O may be replaced by Si - N.

[0104] In a specific embodiment, the luminescent material comprises , where x1 + x2 + x3 = 1, where x3 > 0, where 0 < x2 + x3 ≤ 0.2, where y1 + y2 = 1, where particularly 0 ≤ y2 ≤ 0.2, where A' comprises one or more elements selected from the group consisting of lanthanide elements, and where B' comprises one or more elements selected from the group consisting of Ga, In, and Sc. In an embodiment, x3 is selected from the range of 0.001 - 0.1. In the present invention, particularly x1 > 0, such as > 0.2, such as at least 0.8. Garnets with Y may provide a suitable spectral power distribution.

[0105] In a specific embodiment, up to 10% of B-O can be replaced by Si-N. Here, B in B-O refers to one or more of Al, Ga, In, and Sc (and O refers to oxygen); in a specific embodiment, B-O can refer to A1-O. As described above, in a specific embodiment, x3 can be selected from the range of 0.001 - 0.04. In particular, such a luminescent material can have a suitable spectral distribution (however, see below), have a relatively high efficiency, have a relatively high thermal stability, and allow for a high CRI (optionally in combination with the light of other light sources as described herein). Thus, in a specific embodiment, A can be selected from the group consisting of Lu and Gd. Alternatively or additionally, B can include Ga. Thus, in an embodiment, the luminescent material comprises , where Lu and / or Gd are available. Even more particularly, x3 is selected from the range of 0.001 - 0.1, where 0 < x2 + x3 ≤ 0.1, and where . Further, in a specific embodiment, up to 1% of B-O can be replaced by Si-N. Here, the percentage refers to the number of moles (as known in the art); also see, for example, EP3149108. In yet another specific embodiment, the luminescent material comprises , where x1 + x3 = 1, and where 0 < x3 ≤ 0.2, such as 0.001 - 0.1.

[0106] In a specific embodiment, the light generating device can only comprise a luminescent material selected from cerium-containing garnets. In a more specific embodiment, the light generating device comprises a single type of luminescent material, such as . Thus, in a specific embodiment, the light generating device comprises a luminescent material, where at least 85 wt%, more specifically at least about 90 wt.%, such as more specifically at least about 95 wt% of the luminescent material comprises . Here, where A' includes one or more elements selected from the group consisting of lanthanide elements, and where B' includes one or more elements selected from the group consisting of Ga, In, and Sc, where x1 + x2 + x3 = 1, where x3 > 0, where 0 < x2 + x3 ≤ 0.2, where y1 + y2 = 1, where 0 ≤ y2 ≤ 0.2. In particular, x3 is selected from the range of 0.001 - 0.1. Note that in an embodiment, x2 = 0. Alternatively or additionally, in an embodiment, y2 = 0.

[0107] In a specific embodiment, A can particularly include at least Y, and B can particularly include at least Al.

[0108] Alternatively or additionally, the luminescent material can comprise type luminescent material, where A includes one or more of Y, La, Gd, Tb, and Lu, for example, in an embodiment, A includes one or more of La and Y.

[0109] In embodiments, the luminescent material may alternatively or additionally include one or more of the following: MS:Eu 2+ And / or M2Si5N8:Eu 2+ and / or MAlSiN3:Eu 2+ And / or Ca2AlSi3O2N5:Eu 2+ The luminescent material may include, etc., where M includes one or more of Ba, Sr, and Ca, particularly including at least Sr in the embodiments. Therefore, in the embodiments, the luminescent material may include one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu, and (Ba,Sr,Ca)2Si5N8:Eu. In these compounds, europium (Eu) is present essentially or only in a divalent state, replacing one or more of the divalent cations shown. Typically, the content of Eu does not exceed 10% of the cations. Its content is typically between 0.5% and 10%, and more specifically, the content is typically between 0.5% and 5% relative to the cations it replaces. The term ":Eu" indicates that a portion of the metal ion is replaced by Eu (Eu in this example). 2+ ( ) substitution. For example, assuming the Eu content in CaAlSiN3:Eu is 2%, the correct chemical formula could be (CaO). 98 Eu0. 02AlSiN3. Divalent europium typically substitutes for divalent cations, such as the aforementioned divalent alkaline earth cations, particularly Ca, Sr, or Ba. The material (Ba,Sr,Ca)S:Eu can also be represented as MS:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca); specifically, M in the compound includes calcium or strontium, or calcium and strontium, particularly calcium. Eu is introduced here and substitutes for at least a portion of M (i.e., one or more of Ba, Sr, and Ca). Furthermore, the material (Ba,Sr,Ca)2Si5N8:Eu can also be represented as M2Si5N8:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca); specifically, M in this compound includes Sr and / or Ba. In another specific embodiment, M is composed of Sr and / or Ba (regardless of the presence of Eu), particularly comprising 50% to 100%, more specifically 50% to 90% Ba and 50% to 0%, particularly 50% to 10% Sr, for example Ba1.5Sr0.5Si5N8:Eu (i.e., 75% Ba; 25% Sr). Eu is introduced herein and replaces at least a portion of M (i.e., one or more of Ba, Sr, and Ca). Similarly, the material (Ba,Sr,Ca)AlSiN3:Eu can also be represented as MAlSiN3:Eu, wherein M is selected from one or more of the group consisting of barium (Ba), strontium (Sr), and calcium (Ca); specifically, M in this compound comprises calcium or strontium, or calcium and strontium, more specifically, comprising calcium. Eu is introduced herein and replaces at least a portion of M (i.e., one or more of Ba, Sr, and Ca). Eu is essentially or only in a divalent state, as is known to those skilled in the art.

[0110] In embodiments, the red luminescent material may include one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu, and (Ba,Sr,Ca)2Si5N8:Eu. In these compounds, europium (Eu) is present primarily or only in a divalent state, replacing one or more of the divalent cations shown. Typically, the content of Eu does not exceed 10% of the total cations; its content is particularly in the range of about 0.5% to 10%, and more specifically, its content is in the range of about 0.5% to 5% relative to the cations it replaces. The term ":Eu" indicates that a portion of the metal ion is replaced by Eu (Eu in these examples). 2+ ( ) substitution. For example, assuming the Eu content in CaAlSiN3:Eu is 2%, the correct chemical formula might be (Ca... 0.98 Eu 0.02 AlSiN3. Divalent europium often substitutes for divalent cations, such as the aforementioned divalent alkaline earth cations, especially Ca, Sr, or Ba.

[0111] The material (Ba,Sr,Ca)S:Eu can also be represented as MS:Eu, where M is selected from one or more elements in the group consisting of barium (Ba), strontium (Sr), and calcium (Ca); specifically, M in the compound includes calcium or strontium, or calcium and strontium, more specifically, including calcium. Eu is introduced herein and replaces at least a portion of M (i.e., one or more of Ba, Sr, and Ca).

[0112] Furthermore, the material (Ba,Sr,Ca)2Si5N8:Eu can also be represented as M2Si5N8:Eu, where M is selected from one or more elements in the group consisting of barium (Ba), strontium (Sr), and calcium (Ca); in particular, M in this compound includes Sr and / or Ba. In another specific embodiment, M is composed of Sr and / or Ba (regardless of the presence of Eu), particularly including 50% to 100%, more specifically 50% to 90% Ba and 50% to 0%, particularly 50% to 10% Sr, such as Ba1.5Sr0.5Si5N8:Eu (i.e., 75% Ba; 25% Sr). Eu is introduced herein and replaces at least a portion of M, i.e., replaces one or more of Ba, Sr, and Ca.

[0113] Similarly, the material (Ba,Sr,Ca)AlSiN3:Eu can also be represented as MAlSiN3:Eu, where M is selected from one or more elements in the group consisting of barium (Ba), strontium (Sr), and calcium (Ca); specifically, M in this compound includes calcium or strontium, or calcium and strontium, more specifically, including calcium. Eu is introduced here to replace at least a portion of M (i.e., one or more of Ba, Sr, and Ca).

[0114] The Eu in the aforementioned luminescent materials exists primarily or exclusively in a divalent state, as is known to those skilled in the art.

[0115] The term "luminescent material" in this article specifically refers to inorganic luminescent materials.

[0116] Alternatively or additionally, other luminescent materials may be applied. For example, quantum dots and / or organic dyes may be applied and selectively embedded in a transmissive matrix, such as, for example, polymers, such as PMMA or polysiloxanes, etc.

[0117] Quantum dots are tiny crystals of semiconductor materials, typically only a few nanometers wide or in diameter. When excited by incident light, quantum dots emit light of a color determined by the size and material of the crystal. Therefore, a specific color of light can be produced by adjusting the size of the dot. Most known quantum dots that emit light in the visible light range are based on cadmium selenide (CdSe) with a shell such as cadmium sulfide (CdS) and zinc sulfide (ZnS). Cadmium-free quantum dots, such as indium phosphide (InP), copper indium sulfide (CuInS2), and / or silver indium sulfide (AgInS2), can also be used. Quantum dots exhibit very narrow emission bands, thus displaying saturated colors. Furthermore, the emission color can be easily tuned by adjusting the size of the quantum dot. Any type of quantum dot known in the art can be used in this invention. However, for environmental safety and concerns, cadmium-free quantum dots or at least quantum dots with very low cadmium content are preferred.

[0118] In addition to quantum dots, other quantum confinement structures can be used. In this application, the term "quantum confinement structure" should be understood to mean, for example, quantum wells, quantum dots, quantum rods, tripods, quadrupoles, or nanowires.

[0119] In the embodiments, the body includes a luminescent material, such as a ceramic body, a glass body, or a polymer body, particularly a ceramic body.

[0120] In particular, the term "linearly s-polarized light" may be used instead of "s-polarized light" and similar terms. Furthermore, the term "linearly p-polarized light" may be used instead of "p-polarized light" and similar terms.

[0121] The terms “visible,” “visible light,” or “visible emission,” and similar terms, refer to one or more types of light with wavelengths in the range of about 380–780 nm. In this document, UV may in particular refer to wavelengths selected from the 190–380 nm range, for example, the 200–380 nm range.

[0122] In this document, the terms “light” and “radiation” are used interchangeably unless the context clearly indicates that the term “light” refers only to visible light. Therefore, the terms “light” and “radiation” can refer to UV radiation, visible light, and IR radiation. In specific embodiments, particularly for lighting applications, the terms “light” and “radiation” (at least) refer to visible light.

[0123] The terms "violet light" or "violet emission" and similar terms specifically refer to light with wavelengths in the range of about 380-440 nm. In specific embodiments, the centroid wavelength of violet light may be in the range of 380-440 nm. The terms "blue light" or "blue emission" and similar terms specifically refer to light with wavelengths in the range of about 440-490 nm (including some violet and cyan). In specific embodiments, the centroid wavelength of blue light may be in the range of 440-490 nm. The terms "green light" or "green emission" and similar terms specifically refer to light with wavelengths in the range of about 490-560 nm. In specific embodiments, the centroid wavelength of green light may be in the range of 490-560 nm. The terms "yellow light" or "yellow emission" and similar terms specifically refer to light with wavelengths in the range of about 560-590 nm. In specific embodiments, the centroid wavelength of yellow light may be in the range of 560-590 nm. The terms "orange light" or "orange emission" and similar terms specifically refer to light with wavelengths in the range of about 590-620 nm. In specific embodiments, the centroid wavelength of the orange light may be in the range of 590-620 nm. "Red light" or "red emission" and similar terms particularly refer to light with wavelengths in the range of about 620-750 nm. In specific embodiments, the centroid wavelength of the red light may be in the range of 620-750 nm. "Cyan light" or "cyan emission" and similar terms particularly refer to light with wavelengths in the range of about 490-520 nm. In specific embodiments, the centroid wavelength of cyan light may be in the range of 490-520 nm. "Amber light" or "amber emission" and similar terms particularly refer to light with wavelengths in the range of about 585-605 nm, for example, about 590-600 nm. In specific embodiments, the centroid wavelength of amber light may be in the range of 585-605 nm. The phrase "light having one or more wavelengths within a wavelength range" and similar phrases particularly indicate that the spectral power distribution of light (or radiation) has at least a certain intensity at one or more wavelengths within the wavelength range. For example, the spectral power distribution of a blue light-emitting solid-state light source has a certain intensity at one or more wavelengths in the wavelength range of 440-490nm.

[0124] The term "control" and similar terms specifically refer to at least determining the behavior of an element or monitoring the operation of an element. Therefore, "control" and similar terms as used herein can, for example, refer to applying behavior to an element (determining behavior or monitoring the operation of the element), such as, for example, measuring, displaying, actuating, opening, shifting, changing temperature, etc. In addition, the term "control" and similar terms can also include monitoring. Therefore, the term "control" and similar terms can include applying behavior to an element and applying behavior to an element and monitoring the element. Control of an element can be accomplished using a control system, which can also be referred to as a "controller." The control system and the element can therefore be functionally coupled, at least temporarily or permanently. The element may include a control system. In embodiments, the control system and the element may not be physically coupled. Control can be accomplished via wired and / or wireless control. The term "control system" can also refer to multiple different control systems, which are particularly functionally coupled, and where, for example, one control system may be a master control system, while one or more other control systems may be slave control systems. The control system may include or may be functionally coupled to a user interface.

[0125] The control system can also be configured to receive and execute commands from a remote control. In an embodiment, the control system can be controlled via an app on a device, such as a portable device like a smartphone, iPhone, or tablet. Therefore, the device does not necessarily need to be coupled to the lighting system, but can be (temporarily) functionally coupled to it.

[0126] Therefore, in embodiments, the control system can (also) be configured to be controlled by an app on a remote device. In such embodiments, the control system of the lighting system can be a slave control system or controlled in a slave mode. For example, the lighting system can be identified by a code, specifically a unique code for each individual lighting system. The control system of the lighting system can be configured to be controlled by an external control system that accesses the lighting system based on knowledge of the (unique) code entered through a user interface with optical sensors (e.g., a QR code reader). The lighting system may also include means for communicating with other systems or devices, such as those based on Bluetooth, Thread, WiFi, LiFi, ZigBee, BLE, or WiMAX, or other wireless technologies.

[0127] A system, apparatus, or device may perform actions in a “mode” or “operating mode” or “working mode” or “operable mode”. The term “operable mode” may also be referred to as “operating mode”. Similarly, in a method, actions, stages, or steps may be performed in a “mode” or “operating mode” or “working mode” or “operable mode”. This does not preclude the system, apparatus, or device from being adapted to provide another control mode or multiple other control modes. Likewise, this does not preclude the possibility of performing one or more other modes before and / or after performing a mode.

[0128] However, in embodiments, the control system may be available and is adapted to provide at least a control mode. If other modes are available, the selection of such modes can be performed, in particular, via a user interface, although other options, such as performing modes based on sensor signals or (time) schemes, are also possible. In embodiments, an operating mode may also refer to a system, apparatus, or device that can only operate in a single operating mode (i.e., “on”, without further tunability).

[0129] Therefore, in this embodiment, the control system can be controlled based on one or more of the following: input signals from the user interface, sensor signals (from the sensors), and timers. The term "timer" can refer to a clock and / or a predetermined timing scheme.

[0130] Furthermore, in the embodiments, the luminescent material or diffuser element, or both, may be configured to be in thermal contact with a thermally conductive material. For example, the luminescent material may be configured to be in thermal contact with a thermally conductive element. The thermally conductive element may in particular include a thermally conductive material. The thermally conductive material may in particular have a thermal conductivity of about 20 W / (m²). K), for example, at least about 30 W / (m K), for example, at least about 100 W / (m K), especially at least about 200W / (m The thermal conductivity is approximately 10 W / (m²). In other specific embodiments, the thermally conductive material may in particular have a thermal conductivity of at least about 10 W / (m²). The thermal conductivity of K). In embodiments, the thermally conductive material may include one or more of the following: copper, aluminum, silver, gold, silicon carbide, aluminum nitride, boron nitride, aluminum silicon carbide, beryllium oxide, silicon carbide composites, aluminum silicon carbide, copper-tungsten alloys, copper molybdenum carbide, carbon, diamond, and graphite. Alternatively or additionally, the thermally conductive material may include or be composed of alumina. In embodiments, the thermally conductive element may include one or more of a heat sink, a heat diffuser, and a two-phase cooling device. In other embodiments, the thermally conductive element may be configured to be in thermal contact with one or more of a heat sink, a heat diffuser, and a two-phase cooling device, and, for example, heat may be transferred to such a heat sink, heat diffuser, or two-phase cooling device by another thermally conductive element. If an element can exchange energy with another element through a thermal process, the element is considered to be in a state of "thermal contact" with the other element. Therefore, the elements can be thermally coupled. In embodiments, thermal contact may be achieved through physical contact. In embodiments, thermal contact may be achieved through a thermally conductive material, such as a thermally conductive adhesive (or thermally conductive glue). Thermal contact can also be achieved when the distance between two elements relative to each other is equal to or less than about 10 µm, although larger distances (e.g., up to 100 µm) are also possible. The shorter the distance, the better the thermal contact. In particular, distances of 10 µm or less, such as 5 µm or less, like 1 µm or less, are desirable. This distance can be the distance between the two corresponding surfaces of the individual elements. This distance can be an average distance. For example, two elements may be in physical contact at one or more locations, but not at one or more other locations.

[0131] The light-generating system may be part of or applied to, for example, the following: office lighting systems, home application systems, shop lighting systems, residential lighting systems, accent lighting systems, spotlighting systems, theater lighting systems, fiber optic application systems, projection systems, self-illuminating display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, directional sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, greenhouse lighting systems, horticultural lighting, digital projection, or LCD backlighting. The light-generating system (or luminaire) may be part of, for example, an optical communication system or a disinfection system, or may be applied to, for example, an optical communication system or a disinfection system.

[0132] In another aspect, the invention also provides a lamp or luminaire that includes a light-generating system as defined herein. The luminaire may further include a housing, optical elements, a light-shielding grid, etc. The lamp or luminaire may also include a housing surrounding the light-generating system. The lamp or luminaire may include a light window or a housing opening in the housing through which system light can escape from the housing. In another aspect, the invention also provides a projection device that includes a light-generating system as defined herein. Specifically, a projection device, or "projector" or "image projector," can be an optical device that projects an image (or moving image) onto a surface (such as, for example, a projection screen). The projection device may include one or more light-generating systems as described herein. Thus, in one aspect, the invention also provides a lighting device selected from the group consisting of lamps, luminaires, projector devices, disinfection devices, photochemical reactors, and optical wireless communication devices, which includes a light-generating system as defined herein. The lighting device may include a housing or carrier configured to house or support one or more elements in the light-generating system. For example, in an embodiment, the lighting device may include a housing or carrier configured to house or support one or more of a first light generating device, a second light generating device, an optical device, etc. Attached Figure Description

[0133] Embodiments of the present invention are described below by way of example only, with reference to the accompanying drawings, wherein corresponding reference numerals denote corresponding parts, and in the drawings:

[0134] Figures 1-3 Some embodiments are illustrated schematically;

[0135] Figure 4 The diffusion profile of the flat-top diffuser is schematically depicted;

[0136] Figures 5A-5B Some measurement results are shown;

[0137] Figure 6 Some application examples are illustrated schematically.

[0138] The diagram is not necessarily drawn to scale. Detailed Implementation

[0139] Laser phosphor systems are renowned for their ability to generate high-brightness light and are therefore increasingly used in projection systems, including displays such as cinema projectors, as well as projectors for home, school, and office applications, automotive headlights, searchlights, stage lighting, architectural lighting, and special lighting applications. In many cases, the lighting engine can only produce a single color point defined by the light-emitting converter. In such cases, developing a product family offering different color points is costly because it requires designing, validating, manufacturing, and stocking multiple unique components. In other cases, such as in RGB LCD-based projection systems, maximum brightness is limited by the components used, resulting in a large engine size due to the numerous components and a high system cost due to the large number of specialized parts. One method of combining pump light and emitted light is to use a polarization beamsplitter that applies the pump light, through which a portion of the light is reflected to the emitting material and a portion is transmitted to a diffuser. However, in general, the diffused light appears to be largely depolarized, resulting in relatively high loss of diffused blue light at the combiner where it is combined with the emitted light to form the white output light.

[0140] Since the engine output light in operating mode is likely a superposition of diffused device light and emitted light (converted from device light), its color uniformity depends on the relative spatial and angular brightness distribution of the individual virtual light sources. The actual brightness distribution of the emitted light differs from that of a pure diffuser in principle due to differences in absorption and scattering coefficients, as well as the effective diffusion length. This difference can be reduced by applying additional scattering to one or both of the two color channels. However, not only may the full width at half maximum (FWHM) of the two distributions differ, but the overall shape of the spatial (and angular) distributions may also differ. These two aspects cannot be independently adjusted using a single type of incident optics, therefore color inhomogeneity still exists in the beam because efficiency requirements significantly limit the applicable degree of diffusion and the minimum portion / proportion of the beam emitted from the engine.

[0141] In this embodiment, the present invention provides a light engine architecture comprising two different types of optical devices / functions. Compared to commercial devices that only add a single diffuser, this architecture can achieve superior color uniformity in high-brightness, high-throughput laser-phosphor engines while still maintaining high efficiency.

[0142] This paper proposes, among other things, the use of a first transmissive diffuser to provide sufficient homogenization and beam shaping for the device light (laser) beam directed to the light-emitting converter and the reflective diffuser, so as to obtain the desired spot size and light source extension of the main emitting spot in conjunction with the converging lens; providing an optional second transmissive diffuser to obtain the device beam projected onto the reflective diffuser; providing a first set of two converging lenses to project the device light onto the light-emitting converter; providing a second set of two converging lenses to project the device light onto the reflective diffuser, wherein the effective numerical apertures of the converging lenses in the first and second sets are different, and wherein the lenses in the two sets are identical, but the inter-lens distance in the two sets of converging lenses and the optional distance from the lens to the target (i.e., the diffuser or the emitting material) are also different. By carefully selecting the optimal distance between the two converging lenses in the second lens group (which is less than the optimal distance between the two converging lenses in the first lens group), and optionally combining this with the scattering characteristics of a selected second transmission diffuser (where the diffusion degree of the optional second transmission diffuser is less than that of the first transmission diffuser), it is possible to improve color uniformity while maintaining the same system efficiency compared to a system with two identical optical branches, or to improve both color uniformity and system efficiency simultaneously.

[0143] like Figures 1-3 As shown, an embodiment of a light generation system 1000 is schematically depicted, which includes a first light generation device 110, a second light generation device 120, a light-emitting material 200, a diffuser element 710, an optical device 500, and a control system 300.

[0144] Optical device 500 may include: (a) a first beamsplitter device 1500 (particularly including a dichroic beamsplitter) disposed between the first light generating device 110 and the light emitting material 200; and (b) a second beamsplitter device 2500 (particularly including a polarizing beamsplitter) disposed between the second light generating device 120 and the diffuser element 710. The first beamsplitter device 1500 may include a dichroic beamsplitter, and the second beamsplitter device 2500 includes the first polarizing beamsplitter.

[0145] A first light generating device 110 may be configured to generate first device light 111 having a first peak wavelength λ1. The first light generating device 110 may include a first solid-state light source 10, such as a laser diode. A second light generating device 120 may be configured to generate second device light 121 having a second peak wavelength λ2. The second light generating device 120 may include a second solid-state light source 20, such as a laser diode. In an embodiment, the first peak wavelength λ1 and the second peak wavelength λ2 may be selected from wavelengths in the range of 430-490 nm.

[0146] Specifically, the optical device 500 and the second light generating device 120 are configured such that the second device light 121 (which is incident on the second beam splitter device 2500) includes polarized light having p-polarization or s-polarization.

[0147] Furthermore, the light-emitting material 200 can be configured to convert the first device light 111 received by the light-emitting material 200 into light-emitting material light 201. Additionally, the diffuser element 710 can be configured to diffuse at least a portion of the second device light 121 received thereon, thereby providing diffused second device light 711 while maintaining at least a portion of the polarization of the second device light 121 incident on the diffuser element 710. However, the light-emitting material 200 and the diffuser element 710 can be configured in a reflection mode, as schematically described.

[0148] Furthermore, one of the beam splitter devices 1500 and 2500 can also be configured to combine the light-emitting material light 201 received by the beam splitter device with the diffused second device light 711.

[0149] However, the optical device 500 may further include: (c) a first lens device 1510 disposed between the first beam splitter device 1500 and the light-emitting material 200; and (d) a second lens device 1520 disposed between the second beam splitter device 2500 and the diffuser element 710. The first lens device 1510 may include a first primary lens L11 and a second primary lens L12. The first primary lens L11 and the second primary lens L12 have a first inter-lens distance d1. The second lens device 1520 may include a first primary lens L21 and a second primary lens L22. The first primary lens L21 and the second primary lens L22 have a second inter-lens distance d2. In an embodiment, |1-d2 / d1|≥0.1.

[0150] The optical device 500 may further include a primary angle stretcher TD11 disposed between the first light generating device 110 and the first lens assembly 1510, and a secondary angle stretcher TD12 disposed between the second light generating device 120 and the second lens assembly 1520. Specifically, the primary angle stretcher TD11 may be configured to diffuse the first device light 111 received therefrom, and the secondary angle stretcher TD12 may be configured to diffuse the second device light 121 received therefrom. The primary angle stretcher TD11 may have a first diffusion angle θ1, defined by a full width at half maximum (FWHM), selected from the range of 1° to 15°, such as from 1° to 10°. The secondary angle stretcher TD12 may have a second diffusion angle θ2, defined by a full width at half maximum (FWHM), selected from the range of 1° to 15°, such as from 1° to 10°. In an embodiment, θ2 / θ1 ≥ 1.

[0151] Specifically, the primary angle stretcher TD11 can be configured between the first light generating device 110 and the first beam splitter device 1500, and the secondary angle stretcher TD12 can be configured between the second light generating device 120 and the second beam splitter device 2500.

[0152] Specifically, the light generating system 1000 is configured to generate system light 1001, which includes one or more of luminescent material light 201 and / or diffused second device light 711. The control system 300 can be configured to control the spectral power distribution of the system light 1001, particularly by controlling the light generating device, although other alternatives are also described herein.

[0153] The first solid-state light source 10 and the second solid-state light source 20 can be selected from the group consisting of laser diodes, multi-junction light-emitting diodes, superluminescent diodes, and (laser) diode arrays, respectively. In an embodiment, a laser diode can be used.

[0154] Specifically, the first primary lens L11 has a first primary optical power P11, and the second primary lens L12 has a second primary optical power P12. In this embodiment, P12 > P11. Furthermore, specifically, the first primary lens L21 has a first primary optical power P21, and the second primary lens L22 has a second primary optical power P22. In this embodiment, P22 > P21.

[0155] Specifically, the luminescent material 200 and the first lens device 1510 have a first shortest distance x1, and the diffuser element 710 and the second lens device 1520 have a second shortest distance x2. In one embodiment, x2 ≠ x1, but in other embodiments, x2 = x1.

[0156] As shown in the figure, system 1000 may further include a polarization changing element 810. In an embodiment, polarization changing element 810 may include a λ / 4 waveplate. Specifically, polarization changing element 810 may be disposed between the second beam splitter device 2500 and the second lens device 1520.

[0157] The reference numeral IL refers to an optional integrated optics element, such as an integrating lens, which can be included in optics 500. The reference numeral EL refers to an exit lens, which can be included in optics 500. The reference numeral AP refers to an exit opening or aperture, which can be included in optics 500. The reference numeral M refers to a reflecting mirror, which can be included in optics 500. Multiple reflecting mirrors can be included in optics 500.

[0158] like Figures 2-3As shown, the light generation system 1000 may also include (i) a third light generation device 130 and (ii) a third beam combiner 3500, such as a second polarization beam combiner 3525.

[0159] The third light generating device 130 may be configured to generate third device light 131 having a third peak wavelength λ3. The third light generating device 130 may include a third solid-state light source 30 selected from laser diodes, multi-junction light-emitting diodes, multi-junction light-emitting diodes, superluminescent diodes, and diode arrays.

[0160] In an embodiment, the third device light 131 may include polarized light with p-polarization or s-polarization. Specifically, the first device light 111 may include polarized light with p-polarization or s-polarization, but the polarizations of the first device light 111 and the third device light 131 are different. The second polarization beam combiner 3525 may be disposed upstream of the first beam splitter device 1500 and configured to combine the first device light 111 and the third device light 131 received by the second polarization beam combiner 3525 and guide the combined beam to the first beam splitter device 1500.

[0161] Alternatively, when the wavelength difference between the first device light 111 and the third device light 131 is sufficiently large, the beam combiner 3500 can be a dichroic beam combiner.

[0162] like Figures 2-3 As shown, the second beam splitter device 2500 may include polarization beam splitting and dichroic beam combining functions.

[0163] like Figure 3 As shown, the light generation system 1000 may further include a polarization control element 610. In an embodiment, the polarization control element 610 may include a birefringent rotator. Other embodiments, such as waveplates, delayers, or actuators configured to rotate a third light generation device, have also been described above.

[0164] A polarization control element 610 may be disposed between the second light generating device 120 and the second beam splitter device 2500, and may be configured to control the polarization of the second device light 121 received by the second beam splitter device 2500. Specifically, the second beam splitter device 2500 may be configured to: (a) guide the second device light 121 to the first beam splitter device 1500 or the diffuser element 710 according to the polarization of the second device light 121; and (b) combine the diffused second device light 711 received by the second beam splitter device 2500 with the luminescent material light 201.

[0165] like Figure 2 As shown, the light generation system 1000 may also include a three-stage angle stretcher TD13, which is configured in (i) Figure 2The second beam splitter device 2500 and the second lens device 1520 shown, or (ii) the first beam splitter device 1500 and the second beam splitter device 2500 not shown in the figure. Specifically, the third diffuse angle θ3 of the three-stage angle broadener TD13 is selected from the range of 1-15°, such as the range of 1-10°.

[0166] In the operating mode of the light generation system 1000, the system light 1001 may include both luminescent material light 201 and diffused second device light 711. For example, the correlated color temperature of the system light 1001 can be selected from the range of 1500-12000K, and the color rendering index is at least 65.

[0167] like Figures 1-3 As shown, the rotatable element 1200 may include one or more of the light-emitting material 200 and / or the diffuser element 710, with an embodiment shown in which both are included by the rotatable element 1200. The control system 300 may be configured to control the rotation of the rotatable element 1200 in an operating mode of the light generating system 1000.

[0168] In a specific embodiment, such as Figures 1-2 As schematically depicted, the first beam splitter device 1500 can be configured to have an optical receiving relationship with the second beam splitter device 2500, and can also have the function of a beam combiner.

[0169] In a specific embodiment, for example Figure 3 As schematically depicted, the second beam splitter device 2500 can be configured to receive light from the first beam splitter device 1500 and can also function as a beam combiner. Specifically, the dichroic function can be embodied in the requirement that the element transmits emitted light and reflects light from the s-polarized (second) device, thereby combining the emitted light with the s-polarized (second) device light.

[0170] Transmissive diffusers can be, in particular, transmissive flat-top diffusers with the diffusion angles described above. Similarly, this can also be applied to other angle broadeners. The transmissive diffuser functions primarily in two or three ways: 1. homogenizing the device beam, which may comprise multiple independent collimated laser diode beams (from the laser array), i.e., reducing hot spots in the overall beam; 2. increasing the beam divergence angle to achieve the target spot diameter, such as the target full width at half maximum (FWHM) value, on the reflective diffuser and the luminescent material; 3. optionally, adjusting the spatial (or radial) beam profile on the target plane (i.e., at the reflective diffuser and the luminescent material) to achieve the target radial profile by adjusting the angular profile of the device beam. This can be achieved through engineered diffusers, diffractive diffusers, volumetric and / or surface texture diffusers, or through regular or irregular lens arrays, which can be a single lens array or a pair of lens arrays, such as the well-known compound eye lens array pair or the Köhler integrator.

[0171] The optional third angle stretcher typically has small-angle diffusion characteristics, with an average diffusion angle θ3 that may be smaller than that of the first and second angle stretchers, especially possibly only 50% or even 25% of the latter. The precise function (or type of influence) of TD13 may depend on its location in the system. Depending on the diffusion profile, it may have different effects on the spatial distribution of device light at the reflective diffuser. For example, it can be used to change the slope of the radial irradiance distribution while keeping the beam width (e.g., FWHM) approximately constant. Additionally, it can also diffuse the diffused light reflected from the reflective diffuser, thereby increasing the diameter of the image on the aperture, which is typically located outside the laser phosphor engine but inside the luminaire providing the final output beam (with adjustable beam angle, beam shape, etc.).

[0172] Figure 4 The diffusion process of a flat-top diffuser is schematically depicted. The diffusion angle (θ in this case) is indicated on the x-axis, and the relative intensity is indicated on the y-axis. The arrows indicate the FWHM (full width at half maximum) value of the diffusion angle.

[0173] To achieve high system efficiency and controllable system size (e.g., increased diameter of constrained optical components and beam diameter within a constrained light engine), the device spot projected onto the reflective diffuser and luminescent material can be relatively small, and the light collection angle of the lens in front of these surfaces can be relatively large (e.g., >70°, such as >80°). The numerical aperture of the converging lens assembly may not be achievable by a single lens; therefore, the converging lens assembly typically includes two or even three (converging) lenses. Typically, at least one lens is an aspherical lens, e.g., L1. For L11 and L21 lenses, the absorptivity of blue laser light passing through 10 mm of glass material can be less than 2%, and the coefficient of thermal expansion of the glass material can be less than 1E.-5 For L21 and L22 lenses, the absorptivity of a 10mm thick material can be less than 1%, for example, less than 0.5%, and the coefficient of thermal expansion can be less than 5E. -6 For example, less than 1E -6 Suitable glass materials for one or both lenses, such as N-BK7, H-K9L, or fused silica.

[0174] Reflective diffusers are typically made of surface-textured metal or metallized substrate materials that can substantially maintain polarization. That is, incident linearly polarized light can remain substantially linearly polarized while maintaining its polarization plane; circularly polarized light will remain substantially circularly polarized, although in the opposite direction (i.e., incident left-handed circularly polarized light will return as right-handed circularly polarized light after reflection). However, other reflective diffuser implementations that substantially maintain polarization are also possible.

[0175] The luminescent material can be configured as a static or dynamic converter, such as a rotating disk (“phosphor wheel”) that includes annular (whole / monolithic or segmented) luminescent conversion elements.

[0176] like Figures 2-3 As shown, in an alternative embodiment, the device beam used to excite the luminescent material can consist of two device beams with orthogonal polarization. These two device beams are provided by two device light sources, each typically comprising multiple laser diodes with corresponding collimator lenses, and combined by a polarization beam combiner (or polarization beam splitter, PBS). An additional reflector is introduced so that the three device light sources can be mounted on a shared heat diffuser to disperse and transfer heat to another heat sink, ultimately dissipating it into the environment. In this configuration, when a third device light source is used as the blue light channel, the required power output of this third light source is significantly reduced (typically, for a color temperature of approximately 7000 K, its power is in a 1:4 ratio to the power of the pump device light used to excite the luminescent converter). Therefore, to effectively disperse the thermal power onto the heat diffuser plate, it is preferable to position the second device light between the two first device light sources to achieve the lowest possible laser diode temperature.

[0177] Figure 2The diagram illustrates the configuration achieved experimentally, and the measurement results obtained from it. To optimize the system, the position of the exit lens for a given aperture location needs to be determined first. Both the power output and irradiance profile at the aperture need to be optimized. Measurements have been performed to determine the relationship between luminous flux power and the inter-lens distance d1, with the exit lens position as a parameter. In recreational applications, a requirement is that the irradiance at the edges is not less than 70% of the central irradiance. This requirement can be met by selecting a suitable exit lens position and an inter-lens distance d1 of approximately 3.15 mm, in which case the efficiency remains close to its maximum. Therefore, a setting of d1 = 3.15 mm can be used as a reference.

[0178] The first and second angle broadeners can typically be flat-top diffusers with substantially the same diffusion profile, such as a 4-degree or 5-degree half-height full width (HWHM) profile (sometimes referred to as the diffusion half-angle). Figure 5a illustrates the effect of changing the diffusion angle of the flat-top diffuser TD12 in the blue channel on the illuminance profile. In the figure, the dashed line Ty TH5 represents the illuminance profile of the luminescent material at the exit aperture AP when using the TD11 diffuser with HWHM=5°—the reference profile; Tz TH5 represents the illuminance profile of the blue channel at AP when using the TD12 diffuser with HWHM=5°; and Tz TH4 represents the illuminance profile of the blue channel at AP when using the TD12 diffuser with HWHM=4°.

[0179] As can be clearly seen from Figure 5a, when the HWHM flat-top diffuser is changed from 4° (TH4) to 5° (TH5), the width (e.g., FWHM) of the blue profile (“tristimulus value Z”, Tz) increases. The dashed curve represents the profile of the emission channel (“tristimulus value Y”, Ty) when using the 5° HWHM flat-top diffuser, which is also the target profile of the blue channel. Therefore, some additional spatial broadening of the blue spot may be desirable, but there may also be some desired adjustments to the profile sides to achieve an improved match of good color uniformity in the module's white light output beam.

[0180] To quantify color uniformity, an achromatic lens is used to image the light distribution at the exit aperture (i.e., the light focused onto the aperture AP by the exit lens EL, which is typically located outside the laser-phosphor light engine but inside the luminaire providing the final beam) on a screen. Using a luminance camera, an image of the resulting beam profile can be captured, and the X, Y, and Z tristimulus values ​​can be extracted. Color uniformity is improved by matching the Z tristimulus value profile, primarily influenced by the blue channel, with the Y tristimulus value profile (a measure of the beam profile for the emission channel). The blue channel profile can be adjusted as follows:

[0181] - Use an additional diffuser, and / or

[0182] - Change the inter-lens distance d2, and / or

[0183] – Change the distance from the lens to the reflective diffuser by x2.

[0184] Figure 5B The effects of the first two types of adaptive methods on the output beam profile of the diffused device light are shown. The figure displays cross-sections of normalized tristimulus values ​​extracted from camera measurements, illustrating the effects of different d2 distances (left panel) and different types of added diffusers and their positions (right panel). The tristimulus value Y-map is used as a target for the tristimulus value Z-map. Two channels TH4 (i.e., flat-top diffusers with HWHM of 4°) are used, with an aperture diameter of 6 mm. In the left panel, Ty refers to the illuminance profile distribution of the luminescent material light at AP; Tz 2.50 mm refers to the illuminance profile distribution of the blue channel at AP, where d2 = 2.5 mm; Tz 3.15 mm refers to the illuminance profile distribution of the blue channel at AP, where d2 = 3.15 mm; and Tz 1.5 mm refers to the illuminance profile distribution of the blue channel at AP, where d2 = 1.5 mm. Figure 5B On the right, Ty represents the illuminance profile distribution of the luminescent material light at AP; Tz A represents the illuminance profile distribution of the blue channel at AP with an additional H1 type TD13 diffuser; Tz B represents the illuminance profile distribution of the blue channel at AP without an additional TD13 diffuser; and Tz C represents the illuminance profile distribution of the blue channel at AP with an additional TH1.5 type TD13 diffuser. Figure 5B In all cases, the position of the TD13 diffuser is consistent with... Figure 2 The positions are consistent.

[0185] Here, H1 refers to a Gaussian diffuser with a WHM of 1 degree, TH1 refers to a flat-top diffuser with a WHM of 1 degree, TH1.5 refers to a flat-top diffuser with a WHM of 1.5 degrees, and so on. Tristimulus Y-profile ( Figure 5BThe dashed line Ty in the diagram shows the emission distribution and acts as the target for the blue distribution. The effect of changing the inter-lens distance on the blue channel profile differs from the effect of adding a diffuser. While the FWHM changes with the inter-lens distance, adding a small-angle diffuser has little or no effect on the FWHM. This latter phenomenon can be understood because adding a diffuser can be modeled as a convolution of two diffuser profiles, which, for a combination of flat-top diffusers, affects the slope at the tail but not the FWHM. For a combination of (generalized) Gaussian diffusers, both the FWHM and the slope of the radial profile are affected, and the FWHM can be determined by quadratically summing the individual contributions. In this case, if one contribution is smaller than the other, the change in FWHM is small (e.g., H5×H1→sqrt(25+1)). In the preferred case of using a flat-top diffuser, changing (i.e., reducing) the d2 distance to 2.0 mm yields a very desirable color uniformity (color variation along the beam cross-section). du'v' (≤0.01), and no additional diffuser is required. However, other glowing profiles may exist, requiring the addition of a diffuser to change the shape or slope of the profile.

[0186] Several parameters of interest, as functions of inter-lens distance and diffuse level, have been tested. Results show that the FWHM of the blue channel increases as the inter-lens distance d2 decreases. Furthermore, it was found that the FWHM is essentially independent of the diffuse level of the additional diffuser. The slope of the brightness profile was found to decrease as the inter-lens distance d2 decreases, but decreases as the diffuse level of the additional diffuser increases. Since the deformation of the brightness profile caused by changing d2 or changing the diffuse level is drastically different (i.e., not opposite but complementary), a combination of these two operations can be used to achieve the desired color uniformity.

[0187] Good color uniformity can be achieved when du'v' < 0.010 (related to acceptable color deviation requirements within 5 SDCM). However, good blue channel efficiency is also required. Observations show that better color uniformity than adding a diffuser can be achieved simply by changing the inter-lens distance, while also achieving relatively higher luminous flux. This can be understood as adding a diffuser causing tail widening, which is blocked by the aperture in the luminaire that defines the beam edge. When d1 = 3.15 mm, we found that d2 needs to be set to a value between 1.5 and 2.0 mm, preferably around 1.7 mm. By combining d2 values ​​in the range of 1.75 to 2.25 mm, and combining it with an additional small-angle TD13 lens with a flat-top profile, the overall performance may be further improved.

[0188] As mentioned earlier, the third parameter that can be adjusted to achieve optimal color uniformity of the white light output at the exit aperture is the distance x2 between the reflective diffuser and the converging lens L22. Currently, good results have been achieved when x2 = x1. Several ray tracing simulations have been performed to examine the effect of changing x2. In the first ray tracing modeling experiment, the blue light power at the exit aperture as a function of x2 was measured, with the inter-lens distance d2 used as a parameter.

[0189] In the emission channel, xl = 0.8 mm and d1 = 3.15 mm provide a good emission irradiance profile at the exit aperture, combined with good efficiency. It was found that the blue channel efficiency was optimal at x2 = 0.9 mm when d2 = 2.0 mm. Therefore, optimizing system efficiency may be the reason for choosing x2 > x1, as we observed the best overall performance when d2 is much smaller than d1.

[0190] In the second ray-tracing modeling experiment, with the lens-to-lens distance d2 = 2.0 mm, the blue irradiance profiles at the exit aperture have been measured for multiple x2 values while keeping other parameters constant. In addition, the tristimulus value Z profiles of the ray-tracing simulations mainly corresponding to the blue irradiance profiles at the exit aperture have been performed, with multiple different values taken for the distance x2 between the reflective diffuser RD 710 and the converging lens L22 located only directly in front of the RD, where the lens-to-lens distance d2 = 2.0 mm. In this configuration, TD11 and TD12 are flat-top diffusers (TH4) with HWHM = 4°, there is no TD13 diffuser, and the diameter of the exit aperture is 6 mm. As a reference, the design parameters of the light-emitting channel are x1 = 0.8 mm and d1 = 3.15 mm. From these modeling results, it can be seen that for the selected lens-to-lens distance d2 (close to the preferred value determined when x2 = x1), the change in x2 deviating from x1 results in a decrease in the slope and the FWHM of the blue irradiance profile at the exit aperture. In other words, the distribution becomes sharper and the degree of the flat-top profile decreases. However, if d2 ≈ d1 is chosen, the effect of the change in x2 may be different. For this case, ray-tracing modeling has also been performed. Multiple different values have been taken for the distance x2 between the reflective diffuser RD 710 and the converging lens L22 located directly in front of the RD, where the lens-to-lens distance d2 = 3.25 mm, and the tristimulus value Z profiles of the ray-tracing simulations mainly corresponding to the blue irradiance profiles at the exit aperture have been performed. In this configuration, TD11 and TD12 are flat-top diffusers (TH4) with HWHM = 4°, there is no TD13 diffuser, and the diameter of the exit aperture is 6 mm. As a reference, the design parameters of the light-emitting channel are x1 = 0.8 mm and d1 = 3.15 mm. In this case, it is found that the effect of choosing x2 > x1 is opposite to that of choosing x2 < x1; in the former case, a trend similar to the previous one is observed: the profile becomes sharper and the slope of the irradiance profile decreases. However, in the latter case, the profile becomes more flat-topped and the slope of the irradiance profile increases.

[0191] Therefore, it is found that when using the same lens in the converging lens assembly of the blue diffusing channel and the light-emitting channel, changing x2 relative to x1 (substantially) can be a very viable solution. This allows the adjustment of the blue irradiance profile to match the light-emitting irradiance profile, thereby optimizing color uniformity and system efficiency.

[0192] At Figure 1In an alternative embodiment depicted schematically, an additional beam-shaping angle broadener can be placed between the second beam splitter assembly 2500 (PBS) and the first beam splitter assembly 1500 (DBS) in the blue channel. The advantage of this is that the collection efficiency at the reflective diffuser is not affected because the spot size on the reflective diffuser remains unchanged. Simultaneously, this provides the opportunity to modify the projected diameter of the (blue) diffuser light on the exit aperture, which is typically positioned downstream of the exit lens, independently of the emission projection on that aperture. In this way, the additional small-angle transmission diffuser can substantially have no impact on the size of the device spot projected onto the reflective diffuser, but only on the size of the diffused device spot on the (outer) aperture, independent of the emission projection on that aperture.

[0193] exist Figure 1 In an alternative embodiment depicted schematically, an additional beam-shaping angle broadener may be placed between the second light-generating device 120 (providing a device beam to be diffused by a reflective diffuser) and the PBS (transforming the reflected diffused device light from the unreflected diffused device light projected onto the reflective diffuser). In this configuration, the diffuser broadens the spot projected onto the reflective diffuser and may alter the radial profile as previously described, but in this case, it has no effect on the diffused device light. Matching the projection of the luminescent material and the device light onto the (external) aperture is achieved by optimizing the brightness distribution on the reflective diffuser and the luminescent material. Therefore, an additional transmissive small-angle diffuser may affect the size and / or irradiance profile of the device light spot projected onto the reflective diffuser, but will not affect the projection of the diffused device light onto the (external) aperture.

[0194] In fact, the configuration shown in the attached figure appears to provide relatively good results in balancing system efficiency, irradiation profile, and color uniformity at the exit aperture (given the limited set of components we can use for our experiments).

[0195] Figure 6 An embodiment of a luminaire 2 is schematically depicted, which includes the light generating system 1000 as described above. Reference numeral 301 indicates a user interface that is functionally coupled to a control system 300, which is included in or functionally coupled to the light generating system 1000. Figure 3 An embodiment of lamp 1 is also schematically depicted, which includes a light generating system 1000. Reference numeral 3 indicates a projector device or projector system that can be used to project images (such as projecting onto a wall), which may also include the light generating system 1000. Therefore, Figure 6An embodiment of a lighting device 1600 is schematically depicted, selected from the group consisting of lamp 1, luminaire 2, projector device 3, disinfection device, photochemical reactor, and optical wireless communication device. The lighting device 1600 includes the light generating system 1000 described herein. In embodiments, this lighting device may be lamp 1, luminaire 2, projector device 3, disinfection device, or optical wireless communication device. Lighting light emanating from the lighting device 1600 is indicated by reference numeral 1201. Lighting light 1201 is primarily composed of system light 1001, and therefore may be system light 1001 in specific embodiments. Reference numeral 1300 refers to a space, such as a room. Reference numeral 1305 refers to the floor, reference numeral 1310 refers to the ceiling, and reference numeral 1307 refers to a wall. Other embodiments of the lighting device 1600 may be recreational lighting devices, (recreational) spotlights, stage lighting fixtures, searchlights, etc.

[0196] The term “multiple” refers to two or more. The terms “substantially” or “essentially” and similar terms used herein will be understood by those skilled in the art. “Substantially” or “essentially” may also include embodiments using expressions such as “completely,” “thoroughly,” “all,” etc. Therefore, in embodiments, adjectives such as “substantially” or “essentially” may be omitted. Where applicable, “substantially” or “essentially” may also refer to 90% or higher, such as 95% or higher, particularly 99% or higher, even more particularly 99.5% or higher, including 100%. The term “comprising” also includes embodiments in which the term “comprising” means “consisting of.” The term “and / or” specifically refers to one or more items mentioned before or after “and / or.” For example, “item 1 and / or item 2” and similar phrases may refer to one or more of items 1 and 2. The term “comprising” in one embodiment may mean “consisting of,” but in another embodiment it may also mean “comprising at least the defined kinds and optionally including one or more other kinds.” The use of the verb “comprising” and its various variations does not exclude the presence of other elements or steps not listed in the claims. Unless the context explicitly requires otherwise, the words "comprising," "including," etc., in the specification and claims should be interpreted as inclusive, not exclusive or exhaustive; that is, they should be interpreted as "including but not limited to." The article "a" or "an" preceding an element does not exclude the existence of multiple such elements.

[0197] Furthermore, the terms "first," "second," "third," etc., used in the specification and claims are used to distinguish similar elements and are not necessarily used to describe an order or chronological sequence. It should be understood that these terms can be used interchangeably where appropriate, and the embodiments of the invention described herein may operate in a different order than that described or shown herein.

[0198] This document describes the condition of a device, apparatus, or system during operation. Those skilled in the art will understand that this invention is not limited to the method of operation or the device, apparatus, or system in operation.

[0199] It should be noted that the above embodiments are merely illustrative of the present invention and not limiting, and those skilled in the art can devise many alternative embodiments without departing from the scope of the appended claims.

[0200] In the claims, any reference symbols placed in parentheses should not be construed as limiting the claims.

[0201] This invention can be implemented by hardware comprising multiple different elements and a suitably programmed computer. In the device, apparatus, or system claims listing various means, several means can be implemented by the same hardware. The fact that certain measures are described in mutually different dependent claims does not mean that these measures cannot be effectively combined. In another aspect, this invention provides a software product that, when run on a computer, enables the implementation (one or more embodiments) of the methods described herein.

[0202] The present invention also provides a control system that can control a device, apparatus, or system, or can perform the methods or processes described herein. Furthermore, the present invention provides a computer program product that, when run on a computer functionally coupled to or composed of a device, apparatus, or system, can control one or more controllable elements of the device, apparatus, or system.

[0203] The present invention is also applicable to devices, apparatuses, or systems that include one or more characterizing features described in the specification and / or drawings. The present invention also relates to methods or processes that include one or more characterizing features described in the specification and / or drawings.

[0204] The various aspects discussed in this patent can be combined to provide additional advantages. Furthermore, those skilled in the art will understand that these embodiments can be combined, or more than two embodiments can be combined. Moreover, certain features can form the basis of one or more divisional applications.

Claims

1. A light generating system (1000), comprising a first light generating device (110), a second light generating device (120), a light-emitting material (200), a diffuser element (710), an optical device (500), and a control system (300); wherein: - The optical device (500) includes: (a) A first beam splitter device (1500) is disposed between the first light generating device (110) and the light emitting material (200); (b) a second beam splitter device (2500) is disposed between the second light generating device (120) and the diffuser element (710); - The first light generating device (110) is configured to generate first device light (111) having a first peak wavelength λ1; wherein the first light generating device (110) includes a first solid-state light source (10). - The second light generating device (120) is configured to generate a second device light (121) having a second peak wavelength λ2; wherein the second light generating device (120) includes a second solid-state light source (20). - The optical device (500) and the second light generating device (120) are configured such that when the light from the second device (121) is incident on the second beam splitter device (2500), it includes polarized light having p-polarization or s-polarization; - The luminescent material (200) is configured to convert first device light (111) received by the luminescent material (200) into luminescent material light (201); the diffuser element (710) is configured to diffuse at least a portion of the second device light (121) received by the diffuser element (710), thereby providing diffused second device light (711) while maintaining at least a portion of the polarization of the second device light (121) incident on the diffuser element (710); the luminescent material (200) and the diffuser element (710) are configured in a reflection mode; - One of the beam splitter devices (1500, 2500) is configured to combine the light from the luminescent material (201) received by the beam splitter device and the diffused second device light (711); - The optical device (500) includes: (c) a first lens device (1510) disposed between the first beam splitter device (1500) and the light-emitting material (200); and (d) a second lens device (1520) disposed between the second beam splitter device (2500) and the diffuser element (710); The first lens device (1510) includes a first primary lens (L11) and a second primary lens (L12), wherein the first primary lens (L11) and the second primary lens (L12) have a first inter-lens distance (d1). - The second lens assembly (1520) includes a first-stage lens (L21) and a second-stage lens (L22), wherein the first-stage lens (L21) and the second-stage lens (L22) have a second inter-lens distance (d2); wherein |1-d2 / d1|≥0.1; - The optical device (500) includes: (e) a primary angle stretcher (TD11) disposed between the first light generating device (110) and the first lens device (1510); and (f) a secondary angle stretcher (TD12) disposed between the second light generating device (120) and the second lens device (1520); - The primary angle stretcher (TD11) is configured to diffuse the first device light (111) received by the primary angle stretcher (TD11); the secondary angle stretcher (TD12) is configured to diffuse the second device light (121) received by the secondary angle stretcher (TD12). - The light generating system (1000) is configured to generate system light (1001), the system light (1001) including one or more of luminescent material light (201) and / or diffused second device light (711); and the control system (300) is configured to control the spectral power distribution of the system light (1001).

2. The light generation system (1000) according to claim 1, wherein d2 / d1≤0.9; wherein the first solid-state light source (10) and the second solid-state light source (20) are respectively selected from the group consisting of: laser diode, multi-junction light-emitting diode, superluminescent diode and diode array.

3. The light generation system (1000) according to any one of the preceding claims, wherein the first primary lens (L11) has a first primary optical power P11, the second primary lens (L12) has a second primary optical power P12, and wherein P12>P11; wherein the first primary lens (L21) has a first primary optical power P21, the second primary lens (L22) has a second primary optical power P22, and wherein P22>P21.

4. The light generation system (1000) according to any one of the preceding claims, wherein the primary angle stretcher (TD11) has a first diffusion angle θ1 defined at half-width at half-height in the range of 1° to 15°; wherein the secondary angle stretcher (TD12) has a second diffusion angle θ2 defined at half-width at half-height in the range of 1° to 15°; and wherein θ2 / θ1 ≥ 1.

5. The light generation system (1000) according to claim 4, wherein θ2 / θ1 ≥ 1.

1.

6. The light generating system (1000) according to any one of the preceding claims, wherein the light-emitting material (200) and the first lens device (1510) have a first shortest distance (x1), wherein the diffuser element (710) and the second lens device (1520) have a second shortest distance (x2), wherein x2 ≠ x1.

7. The light generation system (1000) according to claim 6, wherein x2 / x1 ≤ 0.

9.

8. The light generation system (1000) according to any one of the preceding claims includes a polarization changing element (810), wherein the polarization changing element (810) includes a λ / 4 waveplate, and wherein the polarization changing element (810) is disposed between the second beam splitter device (2500) and the second lens device (1520).

9. The light generation system (1000) according to any one of the preceding claims, wherein the first beam splitter device (1500) includes a dichroic beam splitter, and wherein the second beam splitter device (2500) includes a polarizing beam splitter; wherein the first peak wavelength λ1 and the second peak wavelength λ2 are respectively selected from the wavelength range of 430 nm to 490 nm.

10. The light generating system (1000) according to any one of the preceding claims further includes: (i) a third light-generating device (130), and (ii) a polarization combiner (3525), wherein: - The third light generating device (130) is configured to generate third device light (131) having a third peak wavelength λ3; wherein the third device light (131) includes polarized light having p-polarization or s-polarization; wherein the third light generating device (130) includes a third solid-state light source (30) selected from laser diodes, multi-junction light-emitting diodes, multi-junction light-emitting diodes, superluminescent diodes and diode arrays. - Wherein the first device light (111) includes polarized light with p-polarization or s-polarization; wherein the first device light (111) and the third device light (131) have different polarizations; - The polarization combiner (3525) is positioned upstream of the first beam splitter device (1500) and is configured to combine the first device light (111) and the third device light (131) received by the second polarization beam splitter (3525) and guide them to the first beam splitter device (1500).

11. The light generating system (1000) according to any one of the preceding claims, wherein the second beam splitter device (2500) includes polarization beam splitting and dichroic beam combining functions; wherein the light generating system (1000) further includes a polarization control element (610), wherein the polarization control element (610) includes a birefringence rotator, wherein the polarization control element (610) is disposed between the second light generating device (120) and the second beam splitter device (2500), and is configured to control the polarization of the beam splitter device (2500). The polarization of the second device light (121) received by the second beam splitter device (2500); wherein the second beam splitter device (2500) is configured to: (a) guide the second device light (121) to the first beam splitter device (1500) or the diffuser element (710) according to the polarization of the second device light (121); and (b) combine the diffused second device light (711) received by the second beam splitter device (2500) and the luminescent material light (201).

12. The light generation system (1000) according to any one of the preceding claims, wherein the primary angle stretcher (TD11) is disposed between the first light generation device (110) and the first beam splitter device (1500), and wherein the secondary angle stretcher (TD12) is disposed between the second light generation device (120) and the second beam splitter device (2500).

13. The light generation system (1000) according to any one of the preceding claims further includes a third-stage angle stretcher (TD13) configured between (i) the second beam splitter device (2500) and the second lens device (1520) or (ii) the first beam splitter device (1500) and the second beam splitter device (2500); wherein the third-stage angle stretcher (TD13) has a third diffusion angle (θ3) selected from the range of 1° to 10°.

14. A light generating system (1000) according to any one of the preceding claims, wherein in the operating mode of the light generating system (1000), the system light (1001) comprises both the light emitting material light (201) and the diffused second device light (711), having a correlated color temperature selected from the range of 1500K to 12000K and a color rendering index of at least 65; wherein the first device light (111) and the second device light (121) are blue light; wherein the rotatable element (1200) comprises one or more of the light emitting material (200) and the diffuser element (710); wherein the control system (300) is configured to control the rotation of the rotatable element (1200) in the operating mode of the light generating system (1000); and wherein the light emitting material (200) comprises at least A3B5O. 12 Ce-type luminescent materials, wherein A includes one or more of Y, La, Gd, Tb and Lu, and wherein B includes one or more of Al, Ga, In and Sc.

15. A lighting device (1600) selected from the group consisting of: lamps (1), luminaires (2), projection devices (3), stage lighting devices, headlamps, and optical wireless communication devices, said lighting device (1600) comprising a light generating system (1000) according to any one of the preceding claims.

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