A phosphor composition that emits in a wavelength range of 1600 to 2200 nm, and a short-wavelength infrared radiation PCLED

Abstract

A wavelength converting structure is provided. The wavelength converting structure comprises a SWIR phosphor having an emission wavelength in the range of 1600-2200 nm, the SWIR phosphor comprising a structurally disordered garnet material, a sensitizer ion, and at least one rare earth emitter ion. Also provided is a luminescent material having an emission wavelength in the range of 1600-2200 nm. The luminescent material comprises (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u ) [Sc 2-a-b Lu a Cr b Ga d Al e ]{Ga 3-c Al c}O 12 where RE=La, Y, Yb, Nd, Er, Ce, and 0≦u≦2, 0

Description

Technical Field

[0001] This application claims priority to (i) U.S. Patent Application No. 17 / 844,171, entitled "Phosphor Composition Emitting in the Wavelength Range of 1600 - 2200 nm, and Short-Wavelength Infrared Emitting PCLED," filed on June 20, 2022, and (ii) U.S. Patent Application No. 63 / 235,523, entitled "Phosphor Composition Emitting in the Wavelength Range of 1600 - 2200 nm, and Short-Wavelength Infrared Emitting PCLED," filed on August 20, 2021, both of which are incorporated herein by reference in their entirety.

[0002] This application generally relates to phosphor compositions used in phosphor-converted light-emitting devices, and more particularly to phosphor compositions that exhibit broadband infrared emission in the wavelength range of 1600 - 2200 nm.

Background Art

[0003] Semiconductor light-emitting diodes and laser diodes (collectively referred to as "LEDs" in this application) are one of the most efficient light sources currently available. The emission spectrum of an LED typically exhibits a single narrow peak at a wavelength determined by the device structure and the composition of the semiconductor material of which the LED is composed. By suitable selection of the device structure and material system, an LED can be designed to operate at ultraviolet, visible, or infrared wavelengths.

[0004] An LED is combined with one or more wavelength-converting materials (commonly referred to as "phosphors"), which absorb the light emitted by the LED and in response emit light of a longer wavelength. In such a phosphor-converted LED ("pcLED"), the proportion of the light emitted by the LED and absorbed by the phosphor depends on the amount of phosphor material in the optical path of the light emitted by the LED, for example, the concentration of the phosphor material in a phosphor layer disposed on or around the LED, and the thickness of the layer.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The phosphor-converted LED may be designed such that all of the light emitted by the LED is absorbed by one or more phosphors. In that case, the emission from the pcLED will be entirely from the phosphor. In such a case, the phosphor may be selected, for example, to emit light in a spectral region that is not efficiently generated directly by the LED.

[0006] Alternatively, the pcLED may be designed such that only a portion of the light emitted by the LED is absorbed by the phosphor. In that case, the emission from the pcLED will be a mixture of the light emitted by the LED and the light emitted by the phosphor. By suitable selection of the LED, phosphor, and phosphor composition, such a pcLED may be designed, for example, to emit light having a desired color temperature and desired color rendering characteristics.

Means for Solving the Problem

[0007] In one embodiment, a wavelength conversion structure is provided, the wavelength conversion structure having a SWIR phosphor having an emission wavelength in the range of 1600 - 2200 nm, the SWIR phosphor having a structurally irregular garnet material, a sensitizer ion, and at least one rare earth emitter ion. The structurally irregular garnet material has a composition (Gd 3 )[Ga 2 {Ga 3}O 12 and may have 8 - coordinated Gd atoms, 6 - coordinated Ga atoms, and 4 - coordinated Ga atoms. The structurally irregular garnet material may have atoms that occupy more than two lattice sites. Gadolinium may be partially substituted by at least one rare earth element selected from the group consisting of Tm, Ho, La, Y, Yb, Nd, Er, and Ce. The rare earth emitter element may be a combination of Tm and Ho. The rare earth emitter element may be Tm. The SWIR phosphor is (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc vRE u )[Sc 2-a-b-d-e Lu a Cr b Ga d Al e {Ga 3-c Al c}O 12 comprising, wherein RE = La, Y, Yb, Nd, Er, Ce, 0 ≦ u ≦ 2, 0 < v ≦ 1, 0 < x ≦ 1, 0 < y ≦ 0.5, 0 ≦ z ≦ 0.05, 0 < a ≦ 1, 0 < b ≦ 0.3, 0 ≦ c ≦ 3, 0 < d ≦ 1.8, 0 ≦ e ≦ 1.8. The undoped host lattice of the SWIR phosphor is crystallized in a structurally irregular cubic garnet structure type (Gd,Lu,Sc) 3 [Sc,Lu,Ga,Al]) 2 {Ga,Al} 3 O 12 and may have. The SWIR phosphor is Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 , Gd 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 , Gd 2 Ho 0.013 Tm 0.2 Sc 0.67 Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12 and Gd 2.67 Ho 0.01 Tm 0.17 Sc 1.8 Lu 0.3 Ga 2 AlCr 0.05 O 12may have at least one. The wavelength conversion structure may further have an additional IR phosphor, which may emit light in the wavelength range of 1100 to 1700 nm. The additional IR phosphor emits in the range of 1000 to 1700 nm, Ni 2+ or Ni 2+ and Cr 3+ doped spinel, perovskite, and garnet-type IR phosphors may be included. For example, the composition is (Gd) 3 [Sc,Ga,Ni,Zr,Cr] 2 {Ga,Al} 3 O 12 Ni 2+ and Cr 3+ doped garnet phosphors, such as Gd 3 Ga 3.7 ScAl 0.18 Ni 0.02 Zr 0.021 Cr 0.1 O 12 and Gd 3 Ga 4.7 Al 0.18 Ni 0.02 Zr 0.021 Cr 0.1 O 12 are mentioned.

[0008] In another aspect, a luminescent material is provided that emits light having an emission wavelength in the range of 1600 to 2200 nm. The luminescent material includes a structurally irregular garnet material doped with at least one sensitizer ion and at least one rare earth emitter ion. The structurally irregular garnet material is a structurally regular gadolinium gallium garnet (Gd 3 )[Ga 2 {Ga 3}O 12has a composition derived from and has three 8 - coordinated Gd atoms, two 6 - coordinated Ga atoms, and three 4 - coordinated Ga atoms. The structurally irregular garnet material may have atoms that can occupy more than two lattice sites. Gadolinium may be partially substituted by at least one rare - earth element selected from the group consisting of at least one of Tm, Ho, La, Y, Yb, Nd, Er, and Ce. The rare - earth emitter ion may be a combination of Tm and Ho. The rare - earth emitter ion may be Tm. The SWIR phosphor is (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b-d-e Lu a Cr b Ga d Al e {Ga 3-c Al c}O 12 where RE = La, Y, Yb, Nd, Er, Ce, 0 ≦ u ≦ 2, 0 < v ≦ 1, 0 < x ≦ 1, 0 < y ≦ 0.5, 0 ≦ z ≦ 0.05, 0 < a ≦ 1, 0 < b ≦ 0.3, 0 ≦ c ≦ 3, 0 < d ≦ 1.8, 0 ≦ e ≦ 1.8. The SWIR phosphor crystallizes in a structurally irregular cubic garnet structure type (Gd,Lu) 3 (Sc,Lu) 2 (Ga,Al) 3 and may have. The SWIR phosphor is Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 , Gd 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 , Gd 2 Ho 0.013 Tm 0.2 Sc 0.67Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12 and Gd 2.67 Ho 0.01 Tm 0.17 Sc1 .8 Lu 0.3 Ga 2 AlCr 0.05 O 12 may have at least one of.

[0009] In yet another aspect, an IR radiation device is provided, the IR radiation device having a wavelength conversion structure that emits over a wavelength range of 1600 - 2200 nm and has a continuous emission spectrum over a spectral width of at least 500 nm, and a light source configured to emit primary light to the wavelength conversion structure. The SWIR phosphor has (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b-d-e Lu a Cr b Ga d Al e ){Ga 3-c Al c}O 12 where RE = La, Y, Yb, Nd, Er, Ce, 0 ≦ u ≦ 2, 0 < v ≦ 1, 0 < x ≦ 1, 0 < y ≦ 0.5, 0 ≦ z ≦ 0.05, 0 < a ≦ 1, 0 < b ≦ 0.3, 0 ≦ c ≦ 3, 0 < d ≦ 1.8, 0 ≦ e ≦ 1.8.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0011] The following detailed description should be read with reference to the drawings. In the drawings, the same reference numerals represent like elements throughout the different drawings. The drawings are not necessarily to scale and show selected embodiments, and are not intended to limit the scope of the present invention. The detailed description is presented by way of example and is not intended to limit the principles of the present invention.

[0012] In the present application, a phosphor capable of emitting infrared radiation in the short-wavelength infrared radiation range (“SWIR”), more specifically, a SWIR phosphor capable of emitting infrared radiation having a peak wavelength in the range of 1600 nm to 2200 nm, is disclosed. In particular, the SWIR phosphor described in the present application can provide a continuous emission spectrum without generating an emission gap while maintaining a high conversion efficiency in the range of 1600 nm to 2200 nm. For example, the SWIR phosphor disclosed in the present application can provide a continuous emission spectrum over a spectral width of at least 500 nm and may have a minimum spectral power that is at least 20% of the median value spectral power in this range in the emission range from 1600 nm to 2200 nm.

[0013] The SWIR phosphor disclosed in the present application may be excited by light having a wavelength in the blue spectral range. The broadband SWIR phosphor material can efficiently convert short-wavelength blue light into broadband emission of longer SWIR wavelengths. For the sake of economy of terms, infrared radiation may be referred to as “infrared light”, “IR light”, or “light”.

[0014] Also, in the present application, a light source having the SWIR phosphor disclosed in the present application is disclosed. Such a light source has a primary light source such as an LED and a wavelength conversion structure, the latter having the SWIR phosphor and emitting a wavelength in the range of 1600 to 2200 nm as disclosed in the present application, for example, a SWIR pcLED is formed. The use of the broadband SWIR phosphor in such a light source extends the wavelength emitted by the light source up to 2200 nm while providing a continuous spectral power distribution over a wide wavelength range and maintaining a high conversion efficiency.

[0015] The wavelength conversion structure within the light source may further include an additional phosphor. The additional phosphor may have, for example, other SWIR phosphors and may emit wavelengths in other parts of the infrared wavelength range, for example, in the spectral range of 1000 - 1700 nm. Also, the additional phosphor may enable more efficient excitation of the SWIR phosphor.

[0016] Also, in the present application, a wavelength conversion structure device including such a broadband SWIR phosphor is disclosed. The wavelength conversion structure device having a broadband SWIR phosphor may further have an additional phosphor.

[0017] Also, in the present application, the use of a light-emitting device having a broadband SWIR phosphor in a spectroscopic device used for IR absorption spectroscopy applications is disclosed. Instead of a conventional incandescent light source such as a tungsten filament lamp, a light-emitting device having a SWIR phosphor, such as the SWIR pcLED disclosed in the present application, is used. Currently, tungsten filament light sources having a CCT in the range of 2300K are used to cover the spectral range (e.g., from 1000 nm to 3000 μm) required for a SWIR spectrometer system. However, tungsten filament light sources are inferior in mechanical robustness, rapid modulation ability to enhance the sensitivity of the spectrometer, and compactness required for integration of an IR absorption spectrometer into, for example, a small palm-sized device and wearable devices or smartphones. The SWIR phosphors described in the present application combine a broadened emission band suitable for spectrometer applications with high conversion efficiency, which means less power is required and it can be used in miniaturized devices such as wearable devices.

[0018] Another specific use of such SWIR pcLEDs is in the medical field, namely in the area of sensors and endoscopic hyperspectral or multispectral imaging of tissues, where an efficient and high-intensity light source is particularly required (see, for example, the broadband LED light source from visible to short-wavelength-infrared wavelengths for spectral tumor diagnosis by Hayashi et al., Appl. Phys. Lett. 110, 233701 (2017)). Other uses include, for example, the detection and sensing of polymers with different macromolecular compositions that can be easily identified by their specific IR absorption patterns, as well as hyperspectral imaging applications.

[0019] The disclosed light source is efficient and enables further miniaturization and cost reduction of spectrometric systems, sensors, and hyperspectral or multispectral imaging systems that cover a wavelength range of 1600 - 2200 nm, as well as the range of 1000 nm - 2200 nm.

[0020] (SWIR phosphor composition) The SWIR phosphor compound described in the present application comprises (i) a structurally irregular garnet host lattice material; (ii) at least one sensitizer ion; and (iii) at least one rare earth emitter ion.

[0021] The structurally irregular garnet host lattice material is a garnet lattice having a plurality of chemically different doping sites. The irregular structure of the garnet lattice provides multiple hosts, which broadens the emission band of the rare earth emitter ion dopant, resulting in a broadband emission spectrum, while maintaining a sufficient crystal structure to provide high conversion efficiency. The term "structurally irregular" as used in the present application refers to a material having a regular average structure or long-range translational periodicity that can be characterized, for example, by X-ray diffraction experiments. However, the different crystallographic lattice sites are occupied by chemically different atomic species in a more statistical manner, although they are irregular, resulting in a large variation in the chemically slightly different substitutional lattice sites for the sensitizer and emitter ions, and thus inhomogeneously broadened spectral features. This is particularly desirable for the use of SWIR phosphors. The host lattice substantially affects the optical properties of the dopant, and the change in its chemical environment causes a change in the crystal field at the dopant site, resulting in inhomogeneous and thus broader emission. Therefore, the use of a structurally irregular garnet host lattice as described in the present application can assist in providing a more continuous emission spectrum. At the same time, the use of a significantly irregular host lattice may lead to a decrease in conversion efficiency, for example, due to a high concentration of optically active lattice defects. In particular, here Cr 3+ The desired broadening effect of the sensitizing converter is achieved by the addition of a relatively large amount of additive elements such as Lu, Sc, and Al to the garnet material.

[0022] The structurally irregular garnet host lattice composition used in the present application is gadolinium garnet Gd having three 8-coordinate Gd atoms, two 6-coordinate Ga atoms, and three 4-coordinate Ga atoms 3 Ga 2 Ga 3 O 12It can be obtained from. An example of a host lattice composition may include atoms that can occupy two or more lattice sites, such as, for example, Lu and Sc (which can have 8- and 6-coordination) and Al (which can have 6- and 4-coordination). This irregularity is caused by the statistical distribution of one type of element across various lattice points of the garnet structure. For example, lutetium or scandium occupies 8- and 6-coordination lattice sites, while gallium and aluminum can occupy 6- and 4-coordination lattice sites at concentrations above trace amounts or defect levels (>1 atomic %). For example, by chromium(III) and thulium, (Gd,Lu,Sc) 3 [Sc,Lu,Ga,Al,Cr] 2 {Ga,Al} 3 O 12 According to, when the host lattice is further doped, these dopants each occupy a plurality of chemically different 6- or 8-coordination sites, which results from the statistical distribution of the multiple sites occupied by the host lattice elements. As a result, this irregularity provides, for example, the desired broadening of the absorption and radiative transitions of chromium(III) and thulium, respectively. The mixed occupancy of sites results in a plurality of different radiative sites in terms of oxygen ligand charge and distance and / or coordination shape. Such a structurally irregular structure results in the broadening of the constituent radiative bands and, furthermore, a more uniform distribution of spectral power over the desired range.

[0023] An example of a structurally irregular garnet host lattice crystallizes in the cubic garnet structure type (Gd,Lu,Sc) 3 (Sc,Lu,Ga) 2 (Ga,Al) 3 O 12 is. In this example, the composition of the binary oxides forming the garnet phase is selected such that lutetium is incorporated into 8- and 6-coordination cation sites. Alternatively, another example of a structurally irregular host lattice is (Gd,Lu,Sc) 3 Sc 2 (Ga,Al) 3 O 12and it also crystallizes in a cubic garnet structure type and has Sc atoms at both 8 - and 6 - coordinate sites.

[0024] The SWIR phosphor described in the present application is doped with at least one sensitizer ion. The sensitizer ion efficiently absorbs, for example, blue or red pump light from an LED and transfers the absorbed energy to the rare - earth emitter ion, which finally emits light in the desired spectral range. In the blue or red spectral range, in order to efficiently absorb the excitation light from the primary LED light source, the host material may be doped with, for example, Cr(III) as a sensitizer ion on 6 - coordinate sites.

[0025] The SWIR phosphor described in the present application is doped with at least one rare - earth emitter ion or a combination of rare - earth emitter ions to provide emission in the desired spectral range. For example, a SWIR phosphor that provides emission in the wavelength range of 1600 - 2200 nm may have 8 - coordinate sites doped with Tm(III) and Ho(III) or Tm(III) only. Also, doping the host lattice with Er(III) can extend the emission range up to ~1500 nm. The excitation and emission characteristics can be further adjusted by substituting an additional portion of Gd with La, Y, Yb, Nd, or Ce.

[0026] The SWIR phosphor described in the present application may have a composition comprising a phosphor from a type of garnet material having the following composition: (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b-d-e Lu a Cr b Ga d Al e {Ga 3-c Al c}O 12, where RE = La, Y, Yb, Nd, Er, Ce, 0 ≦ u ≦ 2, 0 < v ≦ 1, 0 < x ≦ 1, 0 < y ≦ 0.5, 0 ≦ z ≦ 0.05, 0 < a ≦ 1, 0 < b ≦ 0.3, 0 ≦ c ≦ 3, 0 < d ≦ 1.8, 0 ≦ e ≦ 1.8. Examples of SWIR phosphors having the composition of this type of garnet material are described in more detail below, and these include Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 , Gd 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 , Gd 2 Ho 0.013 Tm 0.2 Sc 0.67 Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12 , and Gd 2.67 Ho 0.01 Tm 0.17 Sc 1.8 Lu 0.3 Ga 2 AlCr 0.05 O 12 are included.

[0027] During the manufacture of the SWIR phosphor composition, for example, during a powder-based phosphor process, a fluxing agent such as a fluoride can be applied to enhance the crystal quality of the SWIR phosphor, and as a result, elements from such a fluxing agent may be incorporated into the SWIR composition. An example of a useful flux system for the SWIR phosphor composition is gadolinium fluoride. As a result of the application of the fluoride flux, some fluoride ions can be incorporated into the final SWIR phosphor composition without degrading the desired properties. Another flux system is, for example, barium fluoride BaF 2 , or AlF 3It may be a hydrate. Another example of a flux system that can be applied includes, for example, silicon oxide, which is beneficial for the manufacture of the ceramic phosphor wavelength conversion structure described in more detail below. This is characterized as a polycrystalline sintered luminescence conversion element that includes the SWIR phosphor described in the present application as at least a part of the polycrystalline matrix. The silica flux agent is added as fine silica powder or may be added in the form of a precursor such as alkoxy tetraethyl orthosilicate that is hydrolyzed during processing, for example. Other parts of the polycrystalline matrix may be, for example, oxides such as aluminum oxide Al 2 O 3 or mixed oxides such as (Al,Ga) 2 O 3 .

[0028] Other compounds may be added to the SWIR phosphor composition if the addition amount is sufficiently small so that the desired properties of the resulting SWIR phosphor are not significantly deteriorated and advantages such as improved crystallization rate or densification are obtained. Examples of such other compounds are, for example, alkaline earth compounds such as MgO, CaO or SrO, or their respective carbonates, zirconium oxide, or hafnium oxide, niobium oxide or tantalum oxide, germanium oxide, silicon dioxide, or other rare earth oxides not explicitly listed in the above list.

[0029] (Infrared light-emitting device having a wavelength conversion structure that emits over a wavelength range of 1600 to 2200 nm) FIG. 1 shows an embodiment of an IR light emitting device that emits IR light over a wavelength range of 1600 to 2200 nm. The IR light emitting device 101 has a wavelength conversion structure 108. The wavelength conversion structure 108 includes at least one SWIR phosphor that emits in the disclosed wavelength range of 1600 to 2200 nm. In addition to the wavelength conversion structure 108, the illumination device 101 has a primary light source 100. The primary light source 100 may be an LED or other suitable light source, including, for example, a resonant cavity light emitting diode (RCLED) and a vertical cavity surface emitting laser diode (VCSEL). For example, the primary light source 100 may be a blue light emitting LED or may include a red light emitting LED. The primary light source 100 emits a first light 104. A portion of the first light 104 is incident on the wavelength conversion structure 108. The wavelength conversion structure 108 absorbs the first light 104 and emits a second light 112. Although not necessarily required, the wavelength conversion structure 108 may be structured such that little or no first light is included in a portion of the final emission spectrum from the device.

[0030] The wavelength conversion structure 108 may have, for example, any of the SWIR phosphors described in this application, and such SWIR phosphors may have a structurally irregular garnet host lattice, at least one sensitizer ion, and at least one rare earth emitting ion. For example, the wavelength conversion structure 108 may have a SWIR phosphor that has a structurally irregular garnet host lattice, Cr(III) sensitizer ions, and rare earth emitter ions of Tm(III) and Ho(III). For example, the wavelength conversion structure 108 may have a SWIR phosphor from a type of garnet material having the following composition: (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b-d-e Lu a Cr b Ga d Al e {Ga 3-c Al c}O 12, where RE = La, Y, Yb, Nd, Er, Ce, 0 ≤ u ≤ 2, 0 < v ≤ 1, 0 < x ≤ 1, 0 < y ≤ 0.5, 0 ≤ z ≤ 0.05, 0 < a ≤ 1, 0 < b ≤ 0.3, 0 ≤ c ≤ 3, 0 < d ≤ 1.8, 0 ≤ e ≤ 1.8.

[0031] The wavelength conversion structure 108 may include, for example, a SWIR phosphor that can be excited in the blue spectral range. For example, the light source 100 may be an AlInGaN and / or InGaN type emitter, and may emit the first light 104 in the wavelength range of 440 - 460 nm. Also, the light source 100 may be a light source that emits the first light 104 in the red spectral range. For example, the light source 100 may be an AlInGaP type emitter that emits wavelengths in the 600 - 650 nm wavelength range, or an InGaAs type emitter that emits wavelengths in the 700 - 1000 nm range. However, the excitation efficiency of these red light emitting light sources for the SWIR phosphor is inferior to that of the light source in the blue wavelength range.

[0032] To improve the conversion efficiency of the SWIR phosphor included in the wavelength conversion structure 108, additional phosphors such as red emitting phosphors may be included. This can be excited by a blue emitting primary LED light source. FIG. 2 shows an IR emitting device 201. The wavelength conversion structure including one or more of the disclosed SWIR phosphor materials may further be combined with a second phosphor system. In FIG. 2, the wavelength conversion structure 218 has a SWIR phosphor portion 208 including a SWIR phosphor that emits in the range of 1600 - 2200 nm described in the present application, and a second phosphor portion 202 as part of the IR emitting device 201. In FIG. 2, the light source 200 may be an LED or any other suitable light source (including, for example, a resonant cavity light emitting diode (RCLED) and a vertical cavity surface emitting laser diode (VCSEL)). The light source 200 emits the first light 204.

[0033] The first light 204 is incident on the wavelength conversion structure 218, which has a SWIR phosphor portion 208 including one or more of the SWIR phosphors described in the present application and a second phosphor system 202. A portion of the first light 204 is incident on the second phosphor portion 202 of the wavelength conversion structure 218. The second phosphor 202 absorbs the first light 204 and emits a third light 206. The third light 206 may have a wavelength range within the excitation range of the SWIR phosphors of the SWIR phosphor portion 208 of the wavelength conversion structure 218. The third light 206 is incident on the SWIR phosphor portion 208. The SWIR phosphor portion 208 absorbs all or a portion of the third light 206 and emits a fourth light 210. Also, a portion of the first light 204 may be incident on the SWIR phosphor portion 208 of the wavelength conversion structure 218. The SWIR phosphor portion 208 may absorb the first light 204 and emit a second light 212, or the first light 204 may pass through the SWIR phosphor portion 208.

[0034] Optionally, the wavelength conversion structure 218 including the SWIR phosphor 208 and the second phosphor 202 may be structured such that little or no first light or third light is present in a portion of the final emission spectrum from the device.

[0035] Examples of such second phosphor systems that may be useful for use in the IR light emitting device 201 include those disclosed in U.S. Patent Application No. 16 / 393,428, entitled "Infrared Light Emitting Device," filed on September 13, 2018. This document is hereby incorporated by reference in its entirety into the present application. In particular, the second phosphor 202 may be, for example, a Eu 2+ doped red emitting material, such as, for example, Ba 0.2 Ca 0.06 Sr 1.64 Si 4.98 Al 0.02 O 0.02 N 7.98 :Eu 0.1 such as M 2-x Si 5-y Al y O y N 8-y :Eu xBSSNE-type phosphor with a composition of (M = Ba, Sr, Ca); for example, Ca .985 SiAlN 3 :Eu 0.015 such as M 1-x SiAlN 3 :Eu x (M = Sr, Ca) composition of CASN-type or SCASN-type phosphor; or for example, (Ba 0.5 Ca 0.5 ) 0.995 LiAl 3 N 4 :Eu 0.005 (M = Ba, Sr, Ca) such as M 1-x LiAl 3 N 4 :Eu x (M = Ba, Sr, Ca); or for example, Sr 0.996 Li 2 Al 1.996 Si 0.004 O 1.996 N 2.004 :Eu 0.004 such as M 1-x Li 2 Al 2-y Si y O 2-y N 2+y :Eu x (M = Ba, Sr, Ca). These may crystallize into regular structural variants of the UCr 4 C 4 structure type, and Ba and Ca occupy specific lattice sites. Similar regular variants are known for oxides such as RbNaLi 6 Si 2 O 8 In (Ba 0.5 Ca 0.5 ) 1-x LiAl 3 N 4 :Eu x In this case, narrow-band emission at ~630 nm is obtained for Eu at the Ba site, while NIR emission at wavelengths >700 nm is obtained for Eu at the Ca site. In other examples, the second phosphor 202 has a composition of Ca 0.985 SiAlN:Eu 0.015It may also be a CASN type phosphor. The CASN type red-emitting phosphor is commercially available, for example, from Mitsubishi Chemical Corporation (BR-101 series).

[0036] The SWIR phosphor described in the present application may further have, for example, a SiO layer having a thickness in the range of 40 nm to 140 nm 2 and Nb 2 O 5 layers alternately used, and can be combined with a dielectric coating structure. A dichroic coating that reflects the primary pump LED light and transmits the phosphor emission light in the SWIR range can be a beneficial solution for enhancing the characteristics of the IR light emitting device. That is, such a dichroic coating can retroreflect blue light without changing the emission spectrum provided by the SWIR phosphor and obtain a chance to be reabsorbed by the wavelength conversion structure.

[0037] In FIG. 2, the wavelength conversion structure 218 is shown as having the SWIR phosphor 208 and the second phosphor system 202 as two separate blocks, but in other embodiments, the SWIR phosphor 208 and the second phosphor system 202 of the wavelength conversion structure may be combined or mixed. The method of forming the wavelength conversion structures 108 and 218 is described in more detail hereinafter.

[0038] (IR light emitting device having a wavelength conversion structure that emits over a wavelength range of 1100 to 2200 nm) The SWIR phosphor described in the present application can further be combined with an additional IR phosphor to broaden the wavelength range of the IR radiation emitted from the IR light emitting device. For example, the SWIR phosphor described in the present application can be combined with an additional IR phosphor that emits IR light at a short wavelength less than the wavelength range of 1600 to 2200 nm of the SWIR phosphor described in the present application, and the wavelength range of the light emitted by the IR light emitting device may be extended to a shorter wavelength.

[0039] Referring again to FIG. 1, the wavelength conversion structure 108 may have, for example, the SWIR phosphors and additional IR phosphors described in the present application. The primary light source 100 emits the first light 104. A portion of the first light 104 is incident on the wavelength conversion structure 108. In this example, the wavelength conversion structure 108 has one or more additional IR phosphors in addition to one or more of the SWIR phosphors described in the present application. The wavelength conversion structure 108 absorbs the first light 104 and emits the second light 112. Since the wavelength conversion structure 108 has both SWIR phosphors and additional IR phosphors, the second light 112 emits IR light over a broad wavelength range including the wavelength of the additional IR phosphors and the wavelength of 1600 - 2200 nm of the SWIR phosphors described in the present application.

[0040] In one example, the additional IR phosphor included is a short-wavelength IR-emitting phosphor disclosed in U.S. Patent Application No. 17 / 035,233, filed on September 23, 2020, entitled "Emission of SWIR pcLEDs and Phosphors in the Range of 1100 - 1700 nm", which application is hereby incorporated by reference in its entirety into the present application. In particular, the additional IR phosphor is one or more Ni 2+ or Ni 2+ and Cr 3+ doped spinels, perovskites, and garnet-type IR phosphors that emit in the range of 1000 - 1700 nm. For example, the additional IR phosphor may be Li 0.5-0.5x (Ga,Sc) 2.5-0.5x-y O 4 :Ni x ,Cr y (where 0 ≤ x ≤ 1, 0 < y ≤ 0.1, 0 ≤ z ≤ 1, 0 ≤ u ≤ 0.2) and may have a spinel-type additional IR phosphor. The device 101 may have an AlInGaP-type LED that emits at 620 - 630 nm within the primary light source 100. More specifically, the device 101 is Li 0.49 Sc 0.05 Ga 2.384 O 4 :Ni 0.013 ,Cr 0.05It may have a wavelength conversion structure 108 including a spinel-type additional IR phosphor, and may have an AlInGaP-type LED emitting radiation at 622 nm as the primary light source 100. By combining such an additional IR phosphor with the SWIR phosphor described in the present application, the IR radiation range of the device 101 is extended to wavelengths shorter than the range of 1600 nm to 2200 nm, and the lighting device 101 emits radiation in the range of 1100 nm to 2200 nm.

[0041] In another example, the additional IR phosphor included may require an additional second phosphor system that is used together with the SWIR phosphor in an IR light-emitting device having a broad IR radiation range similar to the aforementioned second phosphor system. Referring again to FIG. 2, the second phosphor system used with the additional IR phosphor can broaden the spectral range, enabling efficient excitation of the additional IR phosphor, and thus increasing the number of types of primary light sources 200 that can be used in the device 201. That is, the additional second phosphor system used with the additional IR phosphor 202 may or may not be included together with the aforementioned second phosphor system for use with the SWIR phosphor described in the present application. The additional second phosphor system absorbs the first light 204 from the primary light source 200 and emits light outside the wavelength range required to excite the additional IR phosphor. For example, the additional second phosphor system 202 may absorb the first light 204 emitted from a blue or green LED as the primary light source 200. Next, the second phosphor system 202 emits the third light 206 in the red spectral range. The third light 206 emitted from the second phosphor system 202 excites the additional IR phosphor portion 208.

[0042] For example, the device 201 may include a green-to-red emitting phosphor such as Eu 2+ phosphor as the additional second phosphor system 202, and may use a blue light-emitting LED as the primary light source 200. Examples of the red-emitting phosphor used in the additional second phosphor system 202 include (Sr,Ca)AlSiN 3 :Eu and (Ba,Sr,Ca) 2 Si5 -x Al x O x N 8-x : It contains Eu.

[0043] In the exemplary device, the primary light source 200 may be an InGaN emitter that emits blue light. The wavelength conversion structure 218 is an orange - red emission (Ba,Sr) as an additional second phosphor system 202 2 Si 5 N 8 :Eu phosphor, and Li as an additional IR phosphor portion 212 0.5-0.5x (Ga,Sc) 2.5-0.5x-y O 4 :Ni x ,Cr y spinel phosphor, and may have the SWIR phosphor described in the present application. In particular, the device 201 has an InGaN emitter that emits 440 - 460 nm as the primary light source 200, and an orange - red emission phosphor (Ba 0.4 Sr 0.6 ) 2-x Si 5 N 8 :Eu 0.02 as an additional IR phosphor, and Li 0.49 Sc 0.05 Ga 2.384 O 4 :Ni 0.013 ,Cr 0.05 , and a wavelength conversion structure 218 having the SWIR phosphor described in the present application. The additional second phosphor system 202 has a Cr 3+ doped phosphor, which emits in the wavelength range of 700 - 1000 nm and can be excited in the spectral ranges from blue to green and red. The emission of such a Cr 3+ phosphor is re - absorbed by an additional IR phosphor doped with Ni 2+ . The additional second phosphor system 202 may include other Ni 2+ phosphor systems known from the literature. In one example, LaMgGa 11 O 19 :Ni, MgO:Ni, MgF 2 :Ni, Ga 2 O 3: Ni, Ge, or RE 2 AE Mg 2 TV 3 O 12 : Garnets of Ni composition (RE = Y, La, Lu, Gd, Nd, Yb, Tm, Er; AE = Ca, Sr; TV = Si, Ge) are included.

[0044] As shown in FIGS. 1 and 2, the IR light emitting device has a wavelength conversion structure, which may be used together with light sources 100, 200, for example. The light sources 100, 200 may be light emitting diodes (LEDs). In one embodiment, the light emitted by the light emitting diode is absorbed by the phosphor in the wavelength conversion structure and emitted at a different wavelength. FIG. 3 shows an example of a suitable light emitting diode, namely a group-III nitride LED that emits blue light as used in the lighting device shown with respect to FIG. 2. The SWIR phosphor and / or additional IR phosphor are combined with a second phosphor and / or an additional second phosphor that absorbs blue light and emits SWIR light.

[0045] In the following examples, the semiconductor light emitting device is a group-III nitride LED that emits blue or UV light, but semiconductor light emitting devices composed of other materials such as LEDs like laser diodes and other III-V materials, group-III phosphides, group-III arsenides, II-VI materials, ZnO, or Si-based materials can also be used, which is determined by, for example, the range of wavelengths required to excite the SWIR phosphor in the wavelength conversion structure or by the combination of the SWIR phosphor and the second phosphor.

[0046] FIG. 3 shows a group-III nitride LED 1 that can be used in embodiments of the present disclosure. Any suitable semiconductor light-emitting device may be used, and embodiments of the present disclosure are not limited to the device shown in FIG. 3. As is known in the art, the device of FIG. 3 is formed by growing a group-III nitride semiconductor structure on a growth substrate 10. The growth substrate is often sapphire, but may be any suitable substrate, such as SiC, Si, GaN, or a composite substrate. The surface of the growth substrate on which the group-III nitride semiconductor structure is grown may be patterned, roughened, or textured before growth to improve light extraction from the device. The surface of the growth substrate on the opposite side of the growth surface (i.e., the surface from which most of the light is extracted in a flip-chip configuration) may be patterned, roughened, or textured before or after growth, thereby improving light extraction from the device.

[0047] The semiconductor structure has a light-emitting region or active region sandwiched between an n-type region and a p-type region. The n-type region 16 may be grown first. The n-type region 16 has a plurality of layers of different compositions and dopant concentrations, which include, for example, a preparation layer such as a buffer layer or a nucleation layer, and / or a layer designed to facilitate removal of the growth substrate, which may or may not be n-type or intentionally doped, and an n-type or p-type device layer designed for specific optical, material, or electrical properties that are favorable for efficient light emission from the light-emitting region. The light-emitting region or active region 18 is grown on the n-type region. Examples of suitable light-emitting regions include single thick or thin light-emitting layers, or multiple quantum well light-emitting regions including multiple thin or thick light-emitting layers separated by barrier layers. Next, the p-type region 20 may be grown on the light-emitting region. Similar to the n-type region, the p-type region may include a plurality of layers of different compositions, thicknesses, and dopant concentrations, which include layers that are not intentionally doped or n-type layers.

[0048] After growth, a p-contact is formed on the surface of the p-type region. The p-contact 21 often has a plurality of conductive layers, such as a reflective metal and a guard metal, and the latter may prevent or reduce electromigration of the reflective metal. The reflective metal is often silver, but any suitable material may be used. After forming the p-contact 21, a part of the p-contact 21, the p-type region 20, and the active region 18 is removed, a part of the n-type region 16 is exposed, and an n-contact 22 is formed here. The n-contact 22 and the p-contact 21 are electrically insulated from each other by a gap 25, and the gap may be filled with a dielectric such as silicon oxide or any other suitable material. A plurality of n-contact vias may be formed. The n-contact 22 and the p-contact 21 are not limited to the arrangement shown in FIG. 3. The n-contact and the p-contact may be redistributed, and as is known in the art, bond pads having a dielectric / metal stack may be formed.

[0049] To form an electrical connection to the LED1, one or more interconnects 26 and 28 are formed on or electrically connected to the n-contact 22 and the p-contact 21. The interconnect 26 is electrically connected to the n-contact 22 in FIG. 3. The interconnect 28 is electrically connected to the p-contact 21. The interconnects 26 and 28 are electrically insulated from the n-contact and the p-contact 22, 21 and from each other by dielectric layers 24 and a gap 27. The interconnects 26 and 28 may be, for example, solder, stud bumps, gold layers, or any other suitable structure.

[0050] The substrate 10 may be thinned or completely removed. In some embodiments, the surface of the substrate 10 exposed by thinning is patterned, textured, or roughened to improve light extraction.

[0051] In embodiments of the present disclosure, any suitable light-emitting device may be used as a light source. The present invention is not limited to the specific LED shown in FIG. 3. The light source, for example, the LED shown in FIG. 3, is shown by block 1 in FIGS. 4, 5, and 6 hereinafter.

[0052] (Formation of SWIR Phosphor and Wavelength Conversion Structure Containing the SWIR Phosphor) The SWIR phosphor described in the present application can be formed using any suitable method. In one example method, an oxide containing a stable compound, for example, a garnet host, a sensitizer ion, and an element forming a rare earth element, is mixed in a suitable ratio, for example, by ball milling. Next, the mixture is intermediate ball milled and fired at a high temperature, for example, a temperature exceeding 1500 °C. Then, the obtained powder is washed, dried, and sieved, for example, with water, to form a powder of the SWIR phosphor material. This has particles having a diameter within a range defined by the sieve. For example, when using a 50 μm sieve, particles less than 50 μm are obtained. Next, the obtained SWIR phosphor powder is used to form the wavelength conversion structure described in the present application.

[0053] The wavelength conversion structure 108 described with respect to FIG. 1 has one or more SWIR phosphors, or a combination of one or more SWIR phosphors and one or more additional IR phosphors, and can be manufactured, for example, in powder form, ceramic form, or any other suitable form. The wavelength conversion structure 108 is formed in one or more structures, which are formed separately from the light source and can be handled separately from the light source. For example, it may be formed in a pre-configured glass or ceramic tile, or in a structure formed in-situ with the light source, such as a conformal or other coating formed on or above the light source.

[0054] In some embodiments, the wavelength conversion structure 108 may be a powder, for example, dispersed in a transparent matrix, a glass matrix, a ceramic matrix, or any other suitable material or structure. The SWIR phosphor dispersed in the matrix may be, for example, homogenized or formed on tiles disposed on the light source. The glass matrix may be, for example, a low melting point glass having a softening point of less than 1000 °C, or any other suitable glass or other transparent material. The ceramic matrix material may be, for example, a fluoride salt such as CaF 2 or any other suitable material.

[0055] The SWIR phosphor, or a combination of the SWIR phosphor and an additional IR phosphor, may be applied, for example, to a powder containing particles having an average diameter in the range of 3 to 50 μm to form a wavelength conversion structure. The powder may be dispersed in a curable polysiloxane-type resin and installed, for example, by means of a dispenser into a package containing a primary emission LED. The powder may also be mixed with a low melting point glass powder, heated to a temperature above the glass softening temperature, and a phosphor may be formed in a glass converter structure (PiG). Alternatively, the SWIR phosphor may be mixed with a silicone resin, molded or attached to a glass substrate, and a phosphor may be formed on the glass structure (PoG).

[0056] The wavelength conversion structure 108 may be formed, for example, by mixing a powder SWIR phosphor, or a combination of a powdered SWIR phosphor and a powdered additional SWIR phosphor, with a transparent material such as silicone, distributing it, or placing it in the optical path in other ways. In powder form, the average particle size (e.g., particle diameter) of the SWIR phosphor and the additional IR phosphor is, in certain embodiments, at least 1 μm, in certain embodiments 50 μm or less, in certain embodiments at least 5 μm, and in certain embodiments 20 μm or less. In certain embodiments, the individual SWIR phosphor particles or the powder SWIR phosphor layer are coated with one or more materials such as silicates, phosphates, and / or one or more oxides, for example, the absorption and emission characteristics are improved, and / or the functional life of the material is extended.

[0057] A wavelength conversion structure including a second phosphor system and / or an additional second phosphor system, such as the wavelength conversion structure 218 described with respect to FIG. 2, can be manufactured using a method similar to the aforementioned method for the wavelength converter 108.

[0058] The SWIR phosphor and the second phosphor, and / or the additional IR phosphor and the additional second phosphor, may be mixed with each other in a single wavelength conversion layer, or may be formed as separate wavelength conversion layers. In a wavelength conversion structure having separate wavelength conversion layers, the SWIR phosphor and the second phosphor, and / or the additional IR phosphor and the additional second phosphor, are laminated, and the second phosphor (and / or the additional second IR phosphor) is disposed between the SWIR phosphor (and / or the additional IR phosphor) and the light source, or the SWIR phosphor (and / or the additional IR phosphor) may be disposed between the second phosphor (and / or the additional second phosphor) and the light source.

[0059] Figures 4, 5, and 6 show an apparatus in which the LED 1 and the wavelength conversion structure 30 are combined. The wavelength conversion structure 30 may be, for example, the wavelength conversion structure 108 including the SWIR phosphor as shown in FIG. 1, or the wavelength conversion structure 218 having the SWIR phosphor and the second phosphor as shown in FIG. 2 according to the foregoing embodiments and examples.

[0060] In FIG. 4, the wavelength conversion structure 30 is directly connected to the LED 1. For example, the wavelength conversion structure may be directly connected to the substrate 10 shown in FIG. 3, or may be directly connected to the semiconductor structure when the substrate 10 is removed.

[0061] In FIG. 5, the wavelength conversion structure 30 is disposed in proximity to the LED 1 but is not directly connected to the LED 1. For example, the wavelength conversion structure 30 may be separated from the LED 1 by an adhesive layer 32, a small gap, or any other suitable structure. In some embodiments, the distance between the LED 1 and the wavelength conversion structure 30 may be, for example, less than 500 μm.

[0062] In FIG. 6, the wavelength conversion structure 30 is spaced apart from the LED 1. In certain embodiments, the distance between the LED 1 and the wavelength conversion structure 30 may be, for example, on the order of millimeters. Such an apparatus may be referred to as a “remote phosphor” apparatus.

[0063] The wavelength conversion structure 30 may be square, rectangular, polygonal, hexagonal, circular, or any other suitable shape. The wavelength conversion structure may be the same size as the LED 1, larger than the LED 1, or smaller than the LED 1.

[0064] Multiple wavelength conversion materials and multiple wavelength conversion structures can be used in a single apparatus.

[0065] In addition to the SWIR phosphor, the second phosphor, the additional IR phosphor, and / or the aforementioned additional second phosphor, the device may also include other wavelength-converting materials such as, for example, conventional phosphors, organic phosphors, quantum dots, organic semiconductors, II-VI or III-V semiconductors, quantum dots of II-VI or III-V semiconductors, or nanocrystals, pigments, polymers, or other light-emitting materials.

[0066] The plurality of wavelength-converting materials may be mixed with each other or formed as separate structures.

[0067] In some embodiments, other materials may be added to the wavelength-converting structure or device, such as, for example, materials that improve optical properties, materials that promote scattering, and / or materials that improve thermal properties. Examples of such materials are (Al,Ga) as a second phase in the polycrystalline ceramic of the structurally irregular cubic garnet SWIR phosphor described in this application. 2 O 3 That is.

[0068] (IR spectrometer) FIG. 7 shows a diagram of an infrared spectrometer 700. A light emitting device having one or more SWIR phosphors as described in the present application, such as 101 and 201 in FIGS. 1 and 2, may be used in a spectrometer device for IR absorption spectroscopy applications. In FIG. 7, the IR spectrometer 700 has an IR light emitting device 710, which may have one or more SWIR phosphors, such as, for example, light emitting devices 101, 201, or a combination of a SWIR phosphor and an additional IR phosphor (each with or without a second phosphor system, or an additional second phosphor system). Also, the IR light source 710 may be an IR light source array as shown below with respect to FIGS. 8A and 8B. The IR spectrometer 700 further has a sensor / detector 730 for sensing IR light, which is, for example, a photoresistor or a photodiode and can be further combined with an optical waveguide element and / or a diffraction element. In one embodiment, the sensor / detector 730 is specially formed to detect IR light, particularly in a miniaturized device, and has, for example, a lead chalcogenide (PbS, PbSe)-based photoresistor detection element formed on a thin film PbS, which may detect IR radiation over a wavelength range of 1000 to 3000 nm. To provide spectral resolution, a sensing element such as a PbS photoresistor may be combined with an array of optical filter elements, such as a bandpass filter. The IR spectrometer 700 further has, for example, a processor 740, and the data received from the sensor / detector 730 may be processed. The processor 740 includes a controller function, and the IR light emitting device 710 and / or the sensor detector 730 may be controlled. Also, as shown in FIG. 7, the IR spectrometer 700 may include the location of the sample 720 when the sample is inserted into the IR spectrometer between the IR light emitting device 710 and the sensor detector 730. However, in another example (not shown), the sensor / detector may be arranged to detect the IR light emitted from the IR light source after being reflected from the sample, for example, outside the IR spectrometer, and as a result, the sensor / detector detects the reflection spectrum.

[0069] During operation, the IR light emitting device 710 emits IR light 705, which may be broadband emission in the range of 1600 - 2200 nm, or may be broadband emission in the range of 1100 - 2200 nm, which depends on the combination of phosphors in the wavelength conversion structure of the IR light emitting device 710. The emitted light enters the sample 720 (or is reflected from the sample 720 depending on the configuration), and the IR light of the IR absorption spectrum is emitted from (or reflected from) the sample 720 and detected by the sensor / detector 730.

[0070] (IR radiation array) Figures 8A - 8B show a cross-sectional view and a top view of an array 800 of SWIR pcLEDs 810, respectively. The SWIR pcLEDs 810 are each structured as the illumination device 101, 201, or 710 as shown in FIGS. 1, 2, and 7, and have a wavelength converter, which has one or more of the SWIR phosphors described in this application contained in the phosphor pixels 806, and the semiconductor diode 812 is disposed on the substrate 802. The wavelength converter includes one or more SWIR phosphors, or a combination of SWIR phosphors and additional IR phosphors, and may or may not have the second phosphor system and / or additional second phosphor systems as described above. Such an array may have any suitable number of SWIR pcLEDs arranged in any suitable manner. In the illustrated example, the array 800 is shown to be formed monolithically on a common substrate, but alternatively, the array of SWIR pcLEDs may be formed from separate individual pcLEDs. The substrate 802 may optionally include a CMOS circuit for driving the LEDs and may be formed from any suitable material.

[0071] Figures 8A - 8B show an array of nine 3×3 pcLEDs, although such an array may include, for example, dozens, hundreds, or thousands of LEDs. Individual LEDs (pixels) may have a width (e.g., side length) of, for example, 1 millimeter (mm) or less, 500 microns or less, 100 microns or less, or 50 microns or less within the plane of the array. The LEDs in such an array are spaced apart from each other by streets or lanes, and the width of the streets or lanes within the plane of the array is, for example, hundreds of microns, 100 microns or less, 50 microns or less, 10 microns or less, or 5 microns or less. In the example shown, rectangular pixels arranged within a symmetric matrix are shown, although the pixels and the array may have any suitable shape or arrangement.

[0072] LEDs having a dimension of about 50 microns or less in the plane of the array (e.g., side length) are typically referred to as microLEDs, and an array of such microLEDs may be referred to as a microLED array.

[0073] An array of LEDs, or a portion of such an array, may be formed as a segmented monolithic structure. Individual LED pixels are electrically insulated from each other by trenches and / or insulating materials, although the electrically insulated segments remain physically connected to each other by a portion of the semiconductor structure.

[0074] Individual LEDs within the LED array may be individually addressable, may be addressable as part of a group or subset of pixels within the array, or may not be addressable. Thus, the light-emitting pixel array is beneficial for any application where fine-grain intensity, spatial and temporal control of the light distribution is required or would benefit. These applications include, but are not limited to, precise special patterning of the light emitted from pixel blocks or individual pixels. Depending on the application, the emitted light may be spectrally distinct, temporally adaptive, and / or environmentally responsive. Such a light-emitting pixel array may provide a pre-programmed light distribution in various intensities, spatial or temporal patterns. The emitted light may be based at least in part on sensor data received, and may be used for optical wireless communication. Associated electronics and optics may be separate at the pixel, pixel block, or device level.

[0075] As shown in FIGS. 9A-9B, the SWIR pcLED array 800 is attached to an electronic circuit board 900, which may have a power and control module 902, a sensor module 904, and an LED attachment region 906. The power and control module 902 receives power and control signals from an external source and receives signals from the sensor module 904, and based thereon, the power and control module 902 controls the operation of the LEDs. The sensor module 904 may receive signals from any suitable sensor, such as a temperature sensor or a light sensor. Alternatively, the SWIR pcLED array 800 may be attached to a board (not shown) separate from the power and control module and the sensor module.

[0076] Individual SWIR pcLEDs may be placed adjacent to the phosphor layer, if necessary, or introduced in combination with or placed on a lens or other optical element disposed on the phosphor layer. Such optical elements, although not shown in the figures, may be referred to as "primary optical elements". Also, as shown in FIGS. 10A-10B, the SWIR pcLED array 800 (e.g., mounted on the electronic circuit board 900) may be arranged in combination with secondary optical elements, such as waveguides, lenses, or both, for use in the intended application. In FIG. 10A, the light emitted by the SWIR pcLED 810 is collected by the waveguide 1002 and directed to the projection lens 1004. The projection lens 1004 may be, for example, a Fresnel lens. In FIG. 10B, the light emitted by the SWIR pcLED 810 is directly collected by the projection lens 1004 without using an intervening waveguide. This arrangement is particularly suitable when the SWIR pcLEDs are spaced sufficiently close to each other and can be used for various applications. In micro-LED display applications, for example, an optical arrangement similar to that shown in FIGS. 10A-10B may be used. Generally, any suitable arrangement of optical elements may be used in combination with the LED arrays described in the present application, depending on the desired application.

[0077] An array of independently operable LEDs may be used in combination with a lens, a lens system, or other optical system (such as those described above) to provide illumination adaptable to a particular purpose. For example, in such an adaptive illumination system, during operation, illumination that varies by wavelength and / or intensity may be provided across the illuminated sample or object and / or may be directed in a desired direction. The controller is configured to receive data indicative of aspects within the sample or the position and spectral characteristics of a person, and based on that information, control the LEDs in the LED array to provide illumination adapted to the scene. Such data can be provided, for example, by an image sensor, or an optical sensor (such as laser scanning) or a non-optical sensor (such as millimeter radar). Such adaptive illumination is becoming increasingly important for mobile devices, VR, and AR applications.

[0078] FIG. 11 schematically shows, as an example, a camera flash system 1100 having a SWIR pcLED array and a lens system 1102. These may be similar to or the same as the systems described above. The flash system 1100 also has a SWIR pcLED driver 1106, which may be controlled by a controller 1104 such as a microprocessor. The controller 1104 may also be coupled to a camera 1107 and a sensor 1108 and operate according to instructions and profiles stored in a memory 1110. The camera 1107 and the adaptive illumination system 1102 may be controlled by the controller 1104 such that their fields of view are adapted.

[0079] Sensor 1108 may have, for example, a position sensor (such as a gyroscope and / or an accelerometer) and / or other sensors that can be used to determine the position, velocity, and orientation of system 1100. Signals from sensor 1108 are supplied to controller 1104 and may be used to determine a suitable operating path for controller 1104 (e.g., which LEDs are currently illuminating the target and which LEDs will illuminate the target after a predetermined time).

[0080] During operation, the illumination from some or all of the pixels of the LED array at 1102 may be adjusted, deactivated, operated at full intensity, or operated at an intermediate intensity. Beam focusing or steering of the light emitted by the LED array at 1102 is electronically implemented by activating one or more subsets of the pixels, enabling dynamic adjustment of the beam shape without moving the optical system or changing the focus of the lens in the lighting device.

[0081] FIG. 12 schematically shows, by way of example, a display (e.g., AR / VR / MR) system 1200. This includes an adaptive light emitting array 1210, a display 1220, a light emitting array controller 1230, a sensor system 1240, and a system controller 1250. A control input is provided to sensor system 1240, while power and user data inputs are provided to system controller 1250. In some embodiments, the modules included in system 1200 can be compactly arranged in a single structure, or one or more elements can be separately attached and connected via wireless communication or wired communication. For example, light emitting array 1210, display 1220, and sensor system 1240 are attached to a headset or glasses, and light emitting controller and / or system controller 1250 are attached separately.

[0082] The light-emitting array 1210 has one or more adaptive light-emitting arrays as described above, and using this, for example, light can be projected in a graphic or object pattern, and an AR / VR / MR system can be supported. In certain embodiments, an array of microLEDs can be used.

[0083] System 1200 can incorporate a wide range of optics into the adaptive light-emitting array 1210 and / or the display 1220. For example, the light emitted by the adaptive light-emitting array 1210 is coupled to the display 1220.

[0084] The sensor system 1240 may have, for example, external sensors such as cameras, depth sensors, or audio sensors that monitor the environment, and internal sensors such as accelerometers or two-axis or three-axis gyroscopes that monitor the AR / VR / MR headset position. Other sensors may include, but are not limited to, barometric pressure sensors, stress sensors, temperature sensors, or any other suitable sensors required for local or remote environmental monitoring. In certain embodiments, the control input may have detected touches or taps, gesture inputs, or controls based on the headset or display position.

[0085] In response to data from the sensor system 1240, the system controller 1250 can send an image or command to the light-emitting array controller 1230. Also, changes or modifications to the image or command can also be made by user data input or automatic data input as needed. User data input may include, but is not limited to, voice commands, tactile feedback, eye or pupil placement, or that provided by a connected keyboard, mouse, or game controller.

[0086] (Ex.) In the following examples, the compositions of the SWIR phosphors described in the present application and pcLEDs containing these SWIR phosphors are described.

[0087] (Example 1) In Example 1, Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 The synthesis of the SWIR phosphor composition of will be described. By mixing 28.7 g of gadolinium oxide (Treibacher, >99.98%), 7.66 g of scandium oxide (Treibacher, 99.99%), 3.65 g of lutetium oxide (Rhodia, 99.99%), 11.6 g of gallium oxide (Dowa Electronics Materials, 4N), 0.236 g of chromium(II) oxide (Alfa Aesar, 98%), 6.22 g of aluminum oxide (Baikowski, SP-DBM), 0.128 g of holmium oxide (K. Rasmus&Co, 4N), 2.027 g of thulium oxide (Alfa Aesar, >99.9%), and 1.01 g of gadolinium fluoride (Materion, 4N), Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 The SWIR phosphor composition was synthesized. These compounds were mixed by planetary ball milling. Next, the mixture was calcined at 1540 °C for 8 hours in an air atmosphere, then ball milling was performed, and then it was calcined at 1510 °C for 8 hours in an air atmosphere. After the second calcination of the mixture, the mixture was pulverized and ball milled to obtain a powder of the SWIR phosphor. The SWIR phosphor powder was washed with water, dried at 300 °C under air, and finally sieved through a 50 μm sieve for sieving.

[0088] In FIG. 13, the Gd obtained in Example 1 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr0.04 O 12 Shows the X-ray powder pattern 1300 (copper radiation) of the SWIR phosphor. The gray line 1310 shows the position and height of the fitted reflections calculated using a cubic garnet structure model. In Example a, the cubic lattice constant of 12.266 Å and a calculated density of 6.38 g / cm 3 are shown.

[0089] Figure 14 shows Gd obtained in Example 1 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 Shows a scanning electron microscope (SEM) image 1400 of the SWIR phosphor powder.

[0090] Figure 15 shows the power reflection spectrum 1500 of Example 1 in the visible spectrum range. The reflection minimum 1510 in the visible spectrum range is in the blue spectrum region of about 450 nm.

[0091] (Example 2) Example 2 shows the formation of a SWIR pcLED containing the SWIR phosphor synthesized in Example 1. The SWIR pcLED containing the SWIR phosphor of Example 1 was formed by mixing the powder of Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0 with a thermosetting silicone resin (the phosphor / silicone weight ratio is 1.6). The mixture of the SWIR phosphor and the thermosetting silicone resin was dispensed into a medium-power LED package containing an InGaN blue emitter (emission wavelength ~450 nm).

[0092] FIG. 16 shows the normalized short-wave infrared emission spectrum 1600 of the SWIR pcLED formed in Example 2. The emission spectrum shows that the emission from the SWIR pcLED covers the range of 1610 - 2130 nm. The minimum emission power 161 and the average emission power 162 with respect to the maximum emission power for the wavelength range of 1610 - 2130 nm are greater than 12% and 53% (dotted line and dashed line), respectively.

[0093] (Example 3) In Example 3, the synthesis of the SWIR phosphor composition of Gd 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 is described. By mixing 29.56 g of gadolinium oxide (Treibacher, >99.98%), 3.39 g of scandium oxide (Treibacher, 99.99%), 3.87 g of lutetium oxide (Rhodia, 99.99%), 12.34 g of gallium oxide (Dowa Electronics Materials, 4N), 0.493 g of chromium(II) oxide (Alfa Aesar, 98%), 6.22 g of aluminum oxide (Baikowski, SP-DBM), 0.255 g of holmium oxide (K. Rasmus&Co, 4N), 2.995 g of thulium oxide (Alfa Aesar, >99.9%), and 1.04 g of gadolinium fluoride (Materion, 4N), the composition Gd 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12The SWI phosphor was synthesized. These compounds were mixed by planetary ball milling. Next, the mixture was calcined at 1540 °C for 8 hours in an air atmosphere, followed by ball milling, and then calcined at 1510 °C for 8 hours in an air atmosphere. After the second calcination of the mixture, the mixture was pulverized and ball milled to obtain a powder of the SWIR phosphor. The SWIR phosphor powder was washed with water, dried in air at 300 °C, and finally sieved through a 50 μm sieve.

[0094] Figure 17 shows the Gd formed in Example 3 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 X-ray powder pattern 1700 (copper radiation) of the SWIR phosphor composition of. The gray line 1710 represents the position and height of the fitting reflection calculated using the cubic garnet structure model. Example a shows a cubic lattice constant of 12.301 Å and a calculated density of 6.62 g / cm 3 of.

[0095] (Example 4) In Example 4, the formation of a SWIR pcLED containing the SWIR phosphor synthesized in Example 3 will be described. The SWIR pcLED containing the SWIR phosphor of Example 3 was prepared under vacuum by mixing the powder of Gd synthesized in Example 3 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 with a thermosetting silicone resin (phosphor / silicone weight ratio 1.6). The mixture of the SWIR phosphor and the thermosetting silicone resin was dispensed into a medium-power LED package containing an InGaN blue emitter (emission wavelength ~450 nm).

[0096] FIG. 18 shows the normalized short-wave infrared emission spectrum 1800 of the SWIR pcLED formed in Example 4. The emission spectrum indicates that the emission from the SWIR pcLED covers a spectral range of 1600 - 2130 nm. For the wavelength range 1610 - 2130 nm, the minimum emission power 181 and the average emission power 182 relative to the maximum emission power are greater than 12% and 46% (dotted line and dashed line), respectively.

[0097] (Example 5) Example 5 shows the formation of a wavelength conversion structure. This structure is a composite ceramic plate containing a SWIR garnet phosphor composition Gd 2 Ho 0.013 Tm 0.2 Sc 0.67 Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12 as the main polycrystalline phase, and additional (Al,Ga) 2 O 3 as a minor phase. By mixing 89.92 g of gadolinium oxide (Treibacher, >99.98%), 11.58 g of scandium oxide (Treibacher, 99.99%), 11.85 g of lutetium oxide (Rhodia, 99.99%), 37.18 g of gallium oxide (Dowa Electronics Materials, 4N), 1.512 g of chromium(II) oxide (Alfa Aesar, 98%), 40.46 g of aluminum oxide (Baikowski, SP-DBM), 0.611 g of holmium oxide (K.Rasmus&Co, 4N), and 9.57 g of thulium oxide (Alfa Aesar, >99.9%), the SWIR phosphor composition Gd 2 Ho 0.013 Tm 0.2 Sc 0.67 Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12was prepared. These compounds were mixed in 99 g of ethanol and 107 μl of tetraethyl orthosilicate (Merck, p.a.) by ball milling with the addition of a dispersant (2 wt% Maliam AKM-0531) to obtain an average particle size of 0.72 μm. After adding a polyvinyl butyral binder and a plasticizer system (Sekisui BL-5, G-260), a ceramic tape was cast, dried, laminated, and laminated. After debinding at 600 °C, the ceramic plate was sintered at 1580 °C for 8 hours in an air atmosphere. The obtained composite ceramic had a thickness of 197 μm and was mainly crystallized in a cubic garnet structure, and the lattice constant was a 0 = 12.160 Å, and a part (Al, Ga) 2 O 3 had a secondary phase.

[0098] Figure 19 shows a scanning electron micrograph 1900 of the sintered SWIR phosphor ceramic. The bright ceramic particles 1910 are the garnet phosphor phase, and the dark ceramic particles 1920 are composed of the secondary phase of (Al, Ga) 2 O 3 .

[0099] (Example 6) According to the recipe in Table 1 below, the SWIR phosphor composite ceramic of Example 5 was coated with a silica and niobia oxide layer to obtain a dichroic coating. The coating was installed on the surface of the sintered ceramic by reactive sputtering using oxygen as a reactive gas and targets of silicon and niobium metals.

[0100]

Table 1

[0101] (Example 7) The ceramic produced in Example 6 was diced into plateletlets of size 1060×1060 μm, and then the resulting converter structure (having an uncoated surface) was made 1 mm 2 in size, having a light-emitting surface of 2 , and was attached to an InGaN primary LED (LUXEON TM , Lumileds) light source that exhibits emission at 440 nm. The converter structure was attached such that the uncoated surface was disposed on the LED.

[0102] FIG. 21 shows the SWIR emission spectrum 2100 of the phosphor-converted LED formed in this example. As seen in FIG. 21, the emission spectrum indicates that the emission from the SWIR pcLED covers the spectral range of 1600 - 2130 nm. In the wavelength range of 1610 - 2130 nm, the minimum emission power 2110 and the average emission power 2120 with respect to the maximum emission power are each greater than 10% and greater than 35%, respectively. Using the devices shown in FIGS. 22A and 22B, the SWIR pcLED of Example 7 was evaluated as a light source for spectroscopy. In FIGS. 22A and 22B, the test device 2200 has the SWIR pcLED formed in this example 2210, which has a blue-emitting InGaN primary LED 1 having a wavelength conversion structure 2. A dichroic coating 3 formed in Example 6 is attached. The SWIR pcLED 2210 is disposed in proximity to the IR spectrometer optical fiber 4. FIG. 22B shows the evaluation sample (polystyrene) 5. The SWIR pcLED 2210 was brought into proximity (a distance of 10 - 20 mm) to the optical fiber of a Nanoquest (registered trademark) FT-IR spectrometer 4 (Ocean Inside), and a reference spectrum was first recorded (FIG. 22) before placing the polystyrene evaluation sample 5 in the optical path. FIG. 23 shows the FT-IR spectrum of the polystyrene evaluation sample.

[0103] (Example 8) Example 8 shows the formation of a light source for a spectrometer. This includes two different phosphors formed in two different wavelength conversion structures, and the emission of the light source is extended to shorter wavelengths. The light source in this example includes the following two wavelength conversion structures: (1) The first wavelength conversion structure is the SWIR phosphor Gd 2.32 Tm 0.18 Sc 1.5 Lu 0.3 Ga 1.81 Al 1.81 Cr 0.1 O 12 as described in the present application. (2) The second ceramic wavelength conversion structure has a garnet structure described in U.S. Patent Application No. 17 / 035,233, entitled "SWIR pcLED and Emission of Phosphors in the Range of 1100 - 1700 nm", filed on September 23, 2020, which has a composition of Gd 3 Ga 3.7 ScAl 0.18 Ni 0.02 Zr 0.021 Cr 0.1 O 12 and a lattice constant of a 0 = 12.32222 Å. The first wavelength conversion structure is formed as a ceramic plate, and the SWIR garnet phosphor composition Gd 2.32 Tm 0.18 Sc 1.5 Lu 0.3 Ga 1.81 Al 1.81 O 12It has and was manufactured using the method described in Example 5. For example, 78.251 g of gadolinium oxide (Treibacher, 3N5), 19.451 g of scandium oxide (Treibacher, 4N), 11.114 g of lutetium oxide (Rhodia, 4N), 31.54 g of gallium oxide (Dowa Electronics Materials, 4N), 1.41 g of chromium(III) oxide (Alfa Aesar, 99%), 17.17 g of gallium oxide (Baikowski, SP-DBM), 6.445 g of thulium oxide (Treibacher, 4N), and 110 μl of tetraethyl orthosilicate (Merck, p.a.) were ground in ethanol to obtain an average particle size of 0.87 μm. After the forming and firing steps as described in Example 5, a ceramic SWIR phosphor ceramic is obtained. This has a unit cell constant a 0 = 12.293 Å. The second wavelength conversion structure was formed according to the description of US Patent Application No. 17 / 035,233, entitled "Emission of SWIR pcLEDs and Phosphors in the Range of 1100 - 1700 nm", filed on September 23, 2020. The first and second ceramic converter structures each have Gd 3 Ga 3.7 ScAl 0.18 Ni 0.02 Zr 0.021 Cr 0.1 O 12 and Gd 2.32 Tm 0.18 Sc 1.5 Lu 0.3 Ga 1.81 Al 1.81 Cr 0.1 O 12 phosphors, are attached to a primary LED light source of 440 nm emission, and an illumination system having a spectral power distribution in the SWIR wavelength range 2400 shown in FIG. 24 is obtained. In FIG. 24, the dashed line 2410 shows Gd 3 Ga 3.7 ScAl 0.18 Ni 0.02 Zr 0.021 Cr 0.1 O 12Shows the spectral power distribution of an illumination system having only a phosphor material. The dotted line 2420 shows Gd excited by a blue-emitting primary LED light source 2.32 Tm 0.18 Sc 1.5 Lu 0.3 Ga 1.81 Al 1.81 Cr 0.1 O 12 Shows the spectral power distribution of an illumination system having only a phosphor material.

[0104] This disclosure is an example and not limiting. In light of this disclosure, further modifications will be apparent to those skilled in the art and are intended to be within the scope of the appended claims.

Claims

1. A wavelength conversion structure comprising a SWIR phosphor having an emission wavelength in the range of 1600 to 2200 nm, wherein the SWIR phosphor has a structurally irregular garnet material, a sensitizer ion, and at least one rare earth emitter ion, the SWIR phosphor has (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b Lu a Cr b Ga d Al e ]{Ga 3-c Al c}O 12, where RE = La, Y, Yb, Nd, Er, Ce, 0 ≦ u ≦ 2, 0 < v ≦ 1, 0 < x ≦ 1, 0 < y ≦ 0.5, 0 ≦ z ≦ 0.05, 0 < a ≦ 1, 0 < b ≦ 0.3, 0 ≦ c ≦ 3, 0 < d ≦ 1.8, 0 ≦ e ≦ 1.8, a wavelength conversion structure.

2. The wavelength conversion structure according to claim 1, wherein the structurally irregular garnet material has a cubic garnet host lattice having an 8-coordinate Gd atom, a 6-coordinate Ga atom, and a 4-coordinate Ga atom.

3. The wavelength conversion structure according to claim 1, wherein the structurally irregular garnet material has one or more atoms selected from the group of Sc, Lu, Ga, and Al, which can occupy two or more lattice sites at a concentration exceeding 1 atomic %.

4. The wavelength conversion structure according to claim 1, wherein the rare earth emitter ions are composed of Tm and Ho.

5. The wavelength conversion structure according to claim 1, wherein the rare earth emitter ion is composed of Tm.

6. The SWIR phosphor is Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr0.04O 12 、Gd 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 、Gd 2 Ho 0.013 Tm 0.2 Sc 0.67 Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12 、およびGd 2.67 Ho 0.01 Tm 0.17 Sc 1.8 Lu 0.3 Ga 2 AlCr 0.05 O 12 The wavelength conversion structure according to claim 1, having at least one of

7. Furthermore, the wavelength conversion structure according to claim 1, having an additional IR phosphor having emission in the wavelength range of 1100 to 1700 nm.

8. The additional IR phosphor emits in the range of 1000 to 1700 nm, and is Ni 2+ or Ni 2+ doped with Cr 3+ The wavelength conversion structure according to claim 7, comprising one or more of spinel, perovskite, and garnet-type IR phosphors doped with

9. A luminescent material that emits light having an emission wavelength in the range of 1600 to 2200 nm, having a structurally irregular garnet material doped with at least one sensitizer ion and at least one rare earth emitter ion, The luminescent material has (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b Lu a Cr b Ga d Al e ]{Ga 3-c Al c}O 12, where RE = La, Y, Yb, Nd, Er, Ce, 0 ≦ u ≦ 2, 0 < v ≦ 1, 0 < x ≦ 1, 0 < y ≦ 0.5, 0 ≦ z ≦ 0.05, 0 < a ≦ 1, 0 < b ≦ 0.3, 0 ≦ c ≦ 3, 0 < d ≦ 1.8, 0 ≦ e ≦ 1.

8.

10. The structurally irregular garnet material has a cubic garnet host lattice having 8-coordinate Gd atoms, 6-coordinate Ga atoms, and 4-coordinate Ga atoms. The luminescent material according to claim 9.

11. The structurally irregular garnet material can occupy two or more lattice sites at a concentration exceeding 1 atomic %. The luminescent material according to claim 9, having one or more atoms selected from the group consisting of Sc, Lu, Ga, and Al.

12. The rare earth emitter ions are composed of Tm and Ho. The luminescent material according to claim 9.

13. The rare earth emitter ions are composed of Tm. The luminescent material according to claim 9.

14. The luminescent material is Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 、 Gd 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 、 Gd 2 Ho 0.013 Tm 0.2 Sc 0.67 Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12 、 and Gd 2.67 Ho 0.01 Tm 0.17 Tm 0.8 Lu 0.3 Ga 2 AlCr 0.05 O 12 The luminescent material according to claim 9, having at least one of them.

15. An IR radiation device, A wavelength conversion structure, A wavelength conversion structure having a SWIR phosphor, wherein the SWIR phosphor has emission over a wavelength range of 1600 - 2200 nm and has a continuous emission spectrum over a spectral width of at least 500 nm. A wavelength conversion structure, A light source configured to emit radiation to the wavelength conversion structure, Having, The SWIR phosphor has (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b Lu a Cr b Ga d Al e ]{Ga 3-c Al c}O 12, where RE = La, Y, Yb, Nd, Er, Ce, 0 ≦ u ≦ 2, 0 < v ≦ 1, 0 < x ≦ 1, 0 < y ≦ 0.5, 0 ≦ z ≦ 0.05, 0 < a ≦ 1, 0 < b ≦ 0.3, 0 ≦ c ≦ 3, 0 < d ≦ 1.8, 0 ≦ e ≦ 1.

8. An IR radiation device.

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