WO2025006259A1

WO2025006259A1 - Ultra-broadband infrared emitter

Info

Publication number: WO2025006259A1
Application number: PCT/US2024/034449
Authority: WO
Inventors: Pieter Johannes Quintus Van Voorst Vader; Erik ROELING; Nicola Bettina Pfeffer
Original assignee: Lumileds LLC
Current assignee: Lumileds LLC
Priority date: 2023-06-27
Filing date: 2024-06-18
Publication date: 2025-01-02
Anticipated expiration: 2025-12-27

Abstract

An illumination device, system, and method of fabricating the device are described. The device includes a light emitting diode (LED) structure having an LED that emits blue light. A phosphor layer of the LED structure partially absorbs a portion of the blue light and emits near infrared light. A plate that is separated from the LED structure absorbs the blue light and transmits the near infrared light. The plate heats up due to absorption of the blue light and emits blackbody radiation with a peak emission larger than the near infrared light. The plate is separated by an air gap or using a non-conductive layer. For a portable spectroscopic device, one or more sensors detect the emitted light impinging on a target.

Description

ULTRA-BROADBAND INFRARED EMITTER

PRIORITY CLAIM

[0001] This application claims the benefit of priority to United States Provisional Patent Application Serial No. 63/523,480, filed June 27, 2023, which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] The present disclosure relates to light emitting diode (LED) structures. In particular, embodiments are directed to LED structures that emit in both the visible and infrared (IR) ranges.

BACKGROUND OF THE DISCLOSURE

[0003] Light emitters are used in a wide variety of applications. For example, the use of solid state light emitters in spectroscopy -based applications has been of increasing interest due to the portability and relatively low cost. Despite this, cost and size issues, among others, still abound for such devices as multiple different emitters in different wavelengths may be incorporated into such devices to provide a desired emission range to enable detection of multifarious materials.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] FIG. 1 shows an example apparatus, in accordance with some examples.

[0005] FIG. 2 illustrates an example of a general device in accordance with some embodiments.

[0006] FIG. 3 illustrates an example LED array, in accordance with some examples.

[0007] FIG. 4 illustrates a cross-section of a single LED from an LED array, in accordance with some examples.

[0008] FIG. 5 illustrates a cross-sectional view of a single-die package architecture, in accordance with some examples. [0009] FIG. 6A illustrates an example spectrum emitted by the lightconverting layer, according to some embodiments.

[0010] FIGS. 6B-6E illustrate example spectrums emitted by the apparatus, according to some embodiments.

[0011] FIGS. 7A-7D illustrate example lighting structures according to some embodiments.

[0012] FIG. 8 illustrates an example system, according to some embodiments.

[0013] FIG. 9 illustrates a top plan view of an example array suitable for implementing embodiments described herein.

[0014] FIG. 10 illustrates an example method of fabricating an illumination device, according to some embodiments.

DETAILED DESCRIPTION

[0015] Material spectroscopy may use one or more light sources covering a diverse wavelength range. In some examples, such wavelength ranges may generally include light in the near- and mid-IR range, respectively about 0.8 pm to about 2.5 pm and up to about 8 pm. LEDs may be preferred as light sources in mobile devices because of the small dimensions of the LEDs. Solid state IR sources mostly emit in the wavelength range between about 0.8 pm and about 2.5 pm. The solid state IR sources include direct emitters and phosphor-converted emitters.

[0016] A phosphor-converted emitter may include an LED that emits light having a shorter (e.g., blue) wavelength, which then pumps a thin layer of a photon-converting material on the LED. The photon-converting material converts the blue photons from the LED to photons with a mostly lower wavelength. With phosphor conversion, wavelengths of up to about 2.5 pm may be produced. The phosphor can be dispersed in an organic carrier (such as Silicone rubber) or a ceramic carrier, such as A12O3.

[0017] In addition, a limited portion of the blue light produced by the LED is converted, with the excess being emitted as the blue light or dissipated via heat. The heat limits for dissipation may be dependent on the material; organic-based carrier materials may be able to withstand temperatures up to about 300 to about 350 degrees C without damage, while inorganic carriers may be able to withstand much higher temperatures (up to several thousand degrees C).

[0018] For spectroscopy applications, for example, mobile spectroscopy applications it may be desirable to use IR wavelengths up to 10 pm. In general, IR radiation is emitted by an object when above absolute zero (0 Kelvin). A perfect emitter is a “black body”, having a dominant wavelength described by Wien’s law, which is approximately 2898 pm /T(K). At room temperature (293 K), the wavelength emitted is about 10 pm. Using Wien’s law, to emit a peak wavelength of about 2.5 pm an object is heated to about 900°C by direct heating. Thus, the peak wavelength may shift with temperature change, which may be used in embodiments in which not only may a steady-state peak wavelength allow the object to act as a radiation source, but in addition use the object as a radiation source during heating up and/or cooling down of the object.

[0019] FIG. 1 shows an example apparatus 100, in accordance with some examples. In some embodiments, other components may be present, while in other embodiments not all of the components may be present. The apparatus 100 may be, for example, a smart phone or portable spectroscopic device. The apparatus 100 may include both a light source 110 and a sensor 120. The sensor 120 may detect radiation associated with a target 104, such as one or more gases. A processor 130 may be used to control various functions of the light source 110 and the sensor 120, including whether or not a shutter is open in an opening 108 of a housing 140 of the apparatus 100. The processor 130 may be configured to determine a concentration of at least one gas based on an output of the at least one sensor. In other embodiments, the processor 130 may be configured to provide an element analysis of a sample (solid, liquid, or gaseous) based on an output of the at least one sensor.

[0020] The apparatus 100 may include one or more LED arrays 112. Each of the one or more LED arrays 112 may include a plurality of LEDs 114 that may produce light as described herein. Each of the one or more LED arrays 112 may be a segmented structure in which the LEDs 114 are divided into a grid of light emitting areas (the LED 114) and non-light emitting areas (between the LEDs 114).

[0021] In general, the LEDs 114 may be formed from one or more inorganic materials (e.g., binary compounds such as gallium arsenide (GaAs), ternary compounds such as aluminum gallium arsenide (AlGaAs), quaternary compounds such as indium gallium phosphide (InGaAsP), gallium nitride (GaN), or other suitable materials), usually either III-V materials (defined by columns of the Periodic Table) or II- VI materials. Each of the LEDs 114 may emit light in the visible spectrum (about 400nm to about 800 nm) or may emit light in the infrared spectrum (above about 800nm). In other embodiments, LEDs that emit in other wavelengths, such as ultraviolet (UV) wavelengths. [0022] The LEDs 114 may be formed by combining n- and p-type semiconductors on a substrate, for example, of sapphire aluminum oxide (A12O3) or silicon carbide (SiC), among others. In particular, various layers are deposited and processed on the substrate during fabrication of the LEDs 114. The surface of the substrate may be pretreated to anneal, etch, polish, etc. the surface prior to deposition of the various layers.

[0023] In general, the various LED layers may be fabricated using epitaxial semiconductor deposition (e.g., by metal organic chemical vapor deposition) to deposit one or more semiconductor layers, metal deposition (e.g., by sputtering), oxide growth, as well as etching, liftoff, and cleaning, among other operations. The substrate may be removed from the LED structure after fabrication and after connection to contacts on a backplane via metal bonding such as via wire or ball bonding. The backplane may be a printed circuit board or wafer containing integrated circuits (ICs), such as a CMOS IC wafer. The semiconductor deposition operations may be used to create an LED with an active region in which electron-hole recombination occurs and the light from the LED 114 is generated. The active region may be, for example, one or more quantum wells. Metal contacts may be used to drive provide current to the n- and p-type semiconductors from the ICs (such as drivers) of the backplane on which the LED 114 is disposed. Methods of depositing materials, layers, and thin films may include, for example: sputter deposition, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma enhanced atomic layer deposition (PEALD), plasma enhanced chemical vapor deposition (PECVD), and combinations thereof, among others.

[0024] In some embodiments, one or more other layers, such as a phosphor-converting layer 112a that contains phosphor particles, may be disposed on each of the LEDs 114 or the one or more LED arrays 112 to convert at least a portion of the light from the LEDs 114 to light of a different wavelength. For example, blue light from GaN LEDs may be converted into near infrared light or white light by the phosphor-converting layer 112a.

[0025] Each of the one or more LED arrays 112 may be a microLED or miniLED array, for example. A microLED array contains thousands to millions of microscopic microLEDs that emit light and that may be individually controlled or controlled in groups of pixels (e.g., 5x5 groups of pixels). The microLEDs are small (e.g., < 0.01 mm on a side) and may provide monochromatic or multi-chromatic light, typically red, green, blue, or yellow using inorganic semiconductor material such as that indicated above. The LEDs may have a size, for example, of about 4 mm², 250 micron x 250 micron, or larger.

[0026] The light source 110 may include at least one lens 116 and/or other optical elements such as reflectors. In different embodiments, a single lens 116 may be disposed over all of the LED arrays 112, multiple lenses 116 may be disposed over all of the LED arrays 112 with a single lens 116 disposed over one or more of the LED arrays 112, or multiple lenses 116 may be disposed over each of the LED arrays 112 with a single lens 116 disposed over one or more of the LEDs 114 of each of the LED arrays 112. The at least one lens 116 and/or other optical elements may direct the light emitted by the one or more LED arrays 112 toward the target 104 as illumination 102.

[0027] The sensor 120 may sense light at the wavelength or wavelengths emitted by the one or more LED arrays 112 and/or radiation that is emitted by the target 104 in response to absorption of the light from the one or more LED arrays 112. Similar to the light source 110, the sensor 120 may include optics (e.g., at least one sensor lens 122) able to collect or redirect radiation 106 that is reflected from and/or emitted by the target 104. The sensor lens 122 may direct the radiation 106 onto one or more multi-pixel detectors 124 to provide data signals. The one or more multi-pixel detectors 124 may include, for example, photodiodes or one or more other detectors capable of detecting light in the wavelength range(s) of interest.

[0028] The one or more multi-pixel detectors 124 may include multiple different arrays to sense visible and/or infrared light (e.g., from the target 104). The one or more multi-pixel detectors 124 may have one or more segments (that are able to sense the same wavelength/range of wavelengths or different wavelength/range of wavelengths), similar to the LED arrays 112.

[0029] In some embodiments, instead of, or in addition to, being provided in the sensor 120, one or more multi-pixel detectors 124 may be provided in the light source 110. In some embodiments, the light source 110 and the sensor 120 may be integrated in a single module, while in other embodiments, the light source 110 and the sensor 120 may be separate modules that are disposed on a printed circuit board (PCB) or other mount. In other embodiments, the light source 110 and the sensor 120 may be attached to different PCBs or mounts.

[0030] The processor 130 may receive the data signals that represents information of the target 104. The processor 130 may additionally control and drive the LEDs 114 in the one or more LED arrays 112 via one or more drivers 132. For example, the processor 130 may optionally control one or more LEDs 114 in the one or more LED arrays 112 independent of another one or more LEDs 114 in the one or more LED arrays 112, so as to illuminate the target 104 in a specified manner. In some embodiments, if multiple detectors are used, one or more of the detectors may detect visible wavelengths and one or more of the detectors may detect infrared wavelengths; like the one or more LED arrays 112, the one or more multi-pixel detectors 124 may be individually controllable by the processor 130.

[0031] The LEDs 114 may be driven in an analog or digital manner, i.e., using a direct current (DC) driver or pulse width modulation (PWM). As shown, a drivers 132 may be used to drive the LEDs 114 in the LED arrays 112, as well as other components, such as the actuators. [0032] The illumination apparatus 100 may also include an input device, for example, a user-activated input device such as a button that is depressed. The light source 110 and sensor 120 may be disposed in a single housing 140. [0033] Inorganic LEDs and LED architectures may be used to create different types of devices. The individual LED pixels in these architectures may have an area of few square mm down to few square pm depending on the LED matrix or display size and pixel per inch characteristics. One approach is to create a monolithic array of LED pixels on an epitaxial wafer and later transfer and hybridize the LED arrays to a backplane to control individual pixels. One embodiment of such monolithic arrays uses metal (e.g., aluminum (Al)- or silver (Ag)-based) side-contacts. These contacts may serve as the electrical cathode for each pixel and also provide reflective sidewalls between the pixels to reduce light scattering and propagation in lateral directions.

[0034] FIG. 2 illustrates an example of a general device in accordance with some embodiments. The device 200 may be a mobile device such as a laptop computer (PC), a tablet PC, a smart phone, or an augmented reality (AR)/virtual reality (VR), an automotive device, or a spectroscopic device for example. Various elements may be provided on the backplane indicated above, while other elements may be local or remote. Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms.

[0035] Modules and components are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a machine readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations. [0036] Accordingly, the term “module” (and “component”) is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general -purpose hardware processor configured using software, the general -purpose hardware processor may be configured as respective different modules at different times. Software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time.

[0037] The electronic device 200 may include a hardware processor (or equivalently processing circuitry) 202 (e.g., a central processing unit (CPU), a GPU, a hardware processor core, or any combination thereof), a memory 204 (which may include main and static memory), some or all of which may communicate with each other via an interlink (e.g., bus) 208. The memory 204 may contain any or all of removable storage and non-removable storage, volatile memory or non-volatile memory. The electronic device 200 may further include a display/light source 210 such as the LEDs described above, or a video display, an alphanumeric input device 212 (e.g., a keyboard), and a user interface (UI) navigation device 214 (e.g., a mouse). In an example, the display/light source 210, input device 212 and UI navigation device 214 may be a touch screen display. The electronic device 200 may additionally include a storage device (e.g., drive unit) 216, a signal generation device 218 (e.g., a speaker), a network interface device 220, one or more cameras 228, and one or more sensors 230, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor such as those described herein. The electronic device 200 may further include an output controller, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.). [0038] The storage device 216 may include a non-transitory machine readable medium 222 (hereinafter simply referred to as machine readable medium) on which is stored one or more sets of data structures or instructions 224 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 224 may also reside, completely or at least partially, within the memory 204 and/or within the hardware processor 202 during execution thereof by the electronic device 200. While the machine readable medium 222 is illustrated as a single medium, the term "machine readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 224.

[0039] The term “machine readable medium” may include any medium that is capable of storing, encoding, or carrying instructions for execution by the electronic device 200 and that cause the electronic device 200 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine-readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of machine-readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Random Access Memory (RAM); and CD-ROM and DVD-ROM disks.

[0040] The instructions 224 may further be transmitted or received over a communications network using a transmission medium 226 via the network interface device 220 utilizing any one of a number of wireless local area network (WLAN) transfer protocols or a SPI or CAN bus. Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks. Communications over the networks may include one or more different protocols, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi, IEEE 802.16 family of standards known as WiMax, IEEE 802.16.4 family of standards, a Long Term Evolution (LTE) family of standards, a Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, a next generation (NG)/6^th generation (6G) standards among others. In an example, the network interface device 220 may include one or more physical jacks (e.g., Ethernet, coaxial, or phonejacks) or one or more antennas to connect to the transmission medium 226.

[0041] Note that the term “circuitry” as used herein refers to, is part of, or includes hardware components such as an electronic circuit, a logic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group), an Application Specific Integrated Circuit (ASIC), a field-programmable device (FPD) (e.g., a field-programmable gate array (FPGA), a programmable logic device (PLD), a complex PLD (CPLD), a high-capacity PLD (HCPLD), a structured ASIC, or a programmable SoC), digital signal processors (DSPs), etc., that are configured to provide the described functionality. In some embodiments, the circuitry may execute one or more software or firmware programs to provide at least some of the described functionality. The term “circuitry” may also refer to a combination of one or more hardware elements (or a combination of circuits used in an electrical or electronic system) with the program code used to carry out the functionality of that program code. In these embodiments, the combination of hardware elements and program code may be referred to as a particular type of circuitry.

[0042] The term “processor circuitry” or “processor” as used herein thus refers to, is part of, or includes circuitry capable of sequentially and automatically carrying out a sequence of arithmetic or logical operations, or recording, storing, and/or transferring digital data. The term “processor circuitry” or “processor” may refer to one or more application processors, one or more baseband processors, a physical central processing unit (CPU), a single- or multi-core processor, and/or any other device capable of executing or otherwise operating computer-executable instructions, such as program code, software modules, and/or functional processes. [0043] The camera 228 may sense light at least the wavelength or wavelengths emitted by the LEDs. The camera 228 may include optical elements (e.g., at least one camera lens) that are able to collect reflected light of illumination that is reflected from and/or emitted by an illuminated region. The camera lens may direct the reflected light onto a multi-pixel sensor (also referred to as a light sensor) to form an image of on the multi-pixel sensor.

[0044] The processor 202 may control and drive the LEDs via one or more drivers. For example, the processor 202 may optionally control one or more LEDs in LED arrays independent of another one or more LEDs in the LED arrays, so as to illuminate an area in a specified manner.

[0045] In addition, the sensors 230 may be incorporated in the camera 228 and/or the light source 210. The sensors 230 may sense visible and/or infrared light and may further sense the ambient light and/or variations/flicker in the ambient light in addition to reception of the reflected light from the LEDs. The sensors may have one or more segments (that are able to sense the same wavelength/range of wavelengths or different wavelength/range of wavelengths), similar to the LED arrays.

[0046] FIG. 3 illustrates an example LED array 300, in accordance with some examples. The LEDs 302, which are segmented in the LED array 300, are separated by non-emitting areas 304. Sets of the LEDs 302 that are driven in parallel may be referred to herein as emitter segments. In some examples, the LEDs 302 can be arranged in a rectilinear array along orthogonal first and second dimensions. In some examples, each of the non-emitting areas 304 can be arranged as an elongated area that extends along one of the first or second dimensions. As shown, at least one of the non-emitting areas 304 can extend in an unbroken line along a full extent of the first rectilinear array. A lens 306 and/or other optical element may be used to shape illumination from the LED array 300.

[0047] FIG. 4 illustrates a cross-section of an LED 400 in an LED array, in accordance with some examples. The LED 400 includes multiple semiconductor layers grown on a substrate 402 (e.g., a sapphire substrate) that are to be fabricated into pixels 404. The substrate 402 may be any substrate, such as Sapphire, capable of having epitaxial layers grown thereon. The substrate 402 may have patterns 402a on which the epitaxial layers are grown. The pixels 404 may be formed from gallium nitride (GaN), having an n-type semiconductor 404a adjacent to the substrate 402, a p-type semiconductor 404c, and an active region 404b between the n-type semiconductor 404a and the p- type semiconductor 404c. The active region 404b may be, for example, a multiple quantum well structure in which light is generated for emission from the pixels 404. After processing, the substrate 402 may be removed in some embodiments.

[0048] Before etching of the epitaxial GaN layers, die layers of chipscale packages (CSP) allowing uniform current distribution and optical coupling may be deposited or otherwise formed. For example, uniform current injection in the p-type semiconductor 404c may be obtained by depositing a Transparent Conductive Oxide (TCO) layer 405 (such as an Indium Tin Oxide (ITO) layer) on the p-type semiconductor 404c.

[0049] To reduce Ag absorption losses, a dielectric spacer 406, such as SiO? or SiN and/or other dielectric material or materials, is deposited or otherwise formed on the TCO layer 405. An array of openings is etched in a uniform distribution within the dielectric spacer 406 over the TCO layer 405 through, for example, lithographic processes (e.g., using a photoresist). A reflective layer 408 (or other optically reflective structure such as a Bragg reflector), such as an Ag mirror, may then be formed on the dielectric spacer 406. The material forming the reflective layer 408 may fill the openings in the dielectric spacer 406 to form eVias 406a and electrically connect the TCO layer 405 and the reflective layer 408. Thus, the eVias 406a may provide uniform current distribution over the area of the p-type semiconductor 404c. The dielectric spacer 406 may combine several different dielectrics to form a composite mirror to reduce light reflected by the Ag mirror and hence lower absorption losses by the Ag mirror. The addition of the composite mirror provides total internal reflection (TIR) at the SiCh/GaN interface to enhance reflection and, as the Ag mirror is not in contact with the p-GaN, a transparent spreading current layer (the TCO layer) is used on the p-GaN.

[0050] In various embodiments, a hard mask 410 is then deposited on the reflective layer 408. The hard mask 410 may be formed from a material substantially denser than a polymer, for example, SiCh, SiC, or aluminum nitride (AIN). The hard mask 410 may have openings to allow current injection from the p-bonding layer (p-BL) to the reflective layer 408. The hard mask 410 may have openings to allow current injection from a p-bonding layer (p-BL) to the reflective layer 408 and thus the p-type semiconductor 404c, and from an n- bonding layer (n-BL) to the n-type semiconductor 404a.

[0051] The hard mask 410 is used to permit etching of a trench, as well as connections to the n-type semiconductor 404a. Note that although (wet or dry) etching is referred to, other techniques may be used to form various layers such as laser drilling, ion-beam formation, etc. To then insulate the pixels 404, one or more sidewall dielectric layers 412, such as SiCh, may be deposited or otherwise formed on the sidewalls of the pixel 404.

[0052] A bonding layer 414 may be disposed on the hard mask 410. The bonding layer 414 may be formed from copper (Cu) and/or Al, for example. In other embodiments, a single dielectric may be used to partially or completely fill the trench. In this case of a single dielectric layer, a conductive layer may be disposed on the single dielectric layer to promote reflection into the semiconductor layers. The trench may be on the order of several microns (e.g., up to about 10 microns), while the sidewall dielectric layers may be considerably thinner, e.g., up to about a few tenths of a micron. The thickness of the sidewall dielectric layers may be dependent on the desired index of refraction created by the structure.

[0053] FIG. 5 illustrates a cross-sectional view of a single-die package architecture, in accordance with some examples. The package architecture 500 illustrates only a single LED die 510 for clarity. The LED die 510 may contain a semiconductor stack fabricated by combining n-type and p-type semiconductors (e.g., the above III-V semiconductors) on a substrate such as sapphire or silicon carbide (SiC). Various layers may be deposited and processed on the substrate during fabrication of the LED as described above. The surface of the substrate may be pretreated to anneal, etch, polish, etc. the surface prior to deposition of the various layers.

[0054] The LED die 510 may also contain contacts fabricated on the semiconductor stack to make electrical contact with different layers of the semiconductor stack. The LED die 510 may be electrically coupled to, for example, a cathode under bump metallization (UBM) (nUBM) 512a and an anode UBM (pUBM) 512b. The nUBM 512a and the pUBM 512b may be patterned and formed from a metal, such as copper (Cu), nickel (Ni), gold (Au), silver (Ag), and/or titanium (Ti), for example, which may be deposited on the LED die 510.

[0055] The nUBM 512a and the pUBM 512b may be electrically coupled to a PCB 520 through a patterned tile metallization 514 that is disposed on a tile 522 (also referred to as a submount). The electrical connection may be formed by direct contact (e.g., thermocompression bonding) or through a solder and reflow process whereby the solder wets to both metal interfaces and forms a solid joint upon cooling. The tile metallization 514 may be formed from a metal, such as Cu, which may be the same as, or different from, the material(s) used to form the nUBM 512a and the pUBM 512b. The tile metallization 514 may entirely overlap the nUBM 512a and the pUBM 512b to ensure electrical contact therebetween.

[0056] The tile 522 may be formed from FR4, a ceramic, or aluminum nitride (AIN), for example. The tile 522 may provide mechanical support for the LED die 510. The tile 522 may be disposed on a Thermal Interface Material (TIM)/electrode layer 524, which may include a metal, such as those above, and may further include thermal epoxy or thermal grease, for example. The TIM/electrode layer 524 may act as an electrode layer, connecting the tile 522 to a heat sink 526 formed, for example, from Al.

[0057] In some embodiments, a light-converting layer 530 containing phosphor particles may be disposed on or adjacent to the LED die 510. The light-converting layer 530 may convert a portion of the light emitted by the LEDs of the LED die 510 to near infrared light, for example. The lightconverting layer 530 may be a continuous layer or may be segmented to be disposed only on the LEDs.

[0058] A secondary emitter layer 534 may be separated from the LED die 510 using a thermally non-conductive structure 532. In some embodiments, the non-conductive structure 532 may be a solid structure that has a thermal conductivity to not adversely affect the layer on which the non-conductive structure 532 is disposed (e.g., less than about 2 or about 3 W/m°C) at the temperature of interest. In some embodiments, the conductive structure 532 may include non-conductive posts with an air gap between the secondary emitter layer 534 and the LED die 510. The air gap may have a thickness of, for example, between about 0.2 mm and 0.3 mm. The secondary emitter layer 534 may partially absorb light from the LED die 510 that has not been converted by the light-converting layer 530 and heat up to an elevated temperature as a result. In particular, the secondary emitter layer 534 may heat up and emit infrared light, while permitting unabsorbed light from the light-converting layer 530 to otherwise pass therethrough, as described in more detail below.

[0059] A lens 536 and/or other optical elements may be disposed over the entire LED die 510 as shown. In some embodiments, the lens 536 may not contact the secondary emitter layer 534. In other embodiments, individual lenses may be disposed over each LED or over sets of LEDs. In some embodiments, the lens 536 (and/or another lens) may also be disposed between the secondary emitter layer 534 and the LED die 510. The light from the secondary emitter layer 534 and the unabsorbed light from the light-converting layer 530 may be adjusted by the lens 536.

[0060] In some embodiments, the phosphor of the light-converting layer 530 enables emission by the LED die 510 of infrared wavelengths of up to about 2.5 pm. This light may be used as booster for infrared wavelengths emitted by the secondary emitter layer 534. FIG. 6A illustrates an example spectrum emitted by the light-converting layer 530, indicating radiant power as a function of wavelength, according to some embodiments.

[0061] FIGS. 6B-6E illustrate example spectrums emitted by the apparatus, according to some embodiments. FIGS. 6B-6E show the various spectrums emitted by the apparatus for different temperatures of the secondary emitter layer 534, specifically 450 °C (FIG. 6B), 550 °C (FIG. 6C), 650 °C (FIG. 6D), and 750 °C (FIG. 6E). As shown, with increasing temperature, the peak emission of the secondary emitter layer 534 shifts to increasingly lower wavelengths and becomes increasingly stronger relative to the emission of the phosphor of the light-converting layer 530. For example, the peak wavelength in FIG. 6C is about 4 pm. [0062] In order for the secondary emitter layer 534 to emit blackbody radiation in the mid-infrared wavelengths, the temperature of the secondary emitter layer 534 may be set to around 550 °C. The secondary emitter layer 534 may be, for example, formed from silicon (Si) or may contain an infrared transparent filler (e.g., Si or A12O3 with filler, for example). In some embodiments, the materials used in the secondary emitter layer 534 may be transparent to the infrared radiation emitted by the phosphor particles in the light-converting layer 530. In some embodiments, the materials used in the secondary emitter layer 534 may absorb at least a substantial portion (e.g., greater than about 25%) of the infrared radiation emitted by the phosphor particles in the light-converting layer 530. The secondary emitter layer 534 may have a thickness of, for example, between about 100 pm and about 700 pm. For example, a pump LED radiative power (radiation from LED die 510) may be about 1.5 W, with about 0.2 W dissipation in the phosphor layer (lightconverting layer 530). The light-converting layer 530 (phosphor layer) may contain a sintered aluminum oxide (A12O3) layer with phosphor dopants. The remaining about 1.3 W is absorbed by the Silicon (secondary emitter layer 534). The peak wavelength of the secondary emitter layer 534 may vary between about 3 pm and about 5 pm and wavelength emitted by the LED die 510 may vary between about 430 nm and about 460 nm, while the wavelength of the light-converting layer 530 may vary between about 1.6 pm and about 2.1 pm (although this range may be broader dependent on the phosphor used). In other embodiments, the peak wavelength of the secondary emitter layer 534 may vary depending on the temperature of the secondary emitter layer 534, which may extend from about 3 pm to about 10 pm in the above-indicated situations in which emissions from the secondary emitter layer 534 are used for spectroscopy (or another application) during heat up and cool down of the secondary emitter layer 534.

[0063] Tuning and an air gap between the LED die 510 and the secondary emitter layer 534 (e.g., Si) may be used to achieve such a temperature. The secondary emitter layer 534 may be doped and/or undoped, each of which may have different tuning characteristics. Tuning may be performed by the processor controlling the driver to change the driving current used to drive the LEDs of the LED die 510. The secondary emitter layer 534 may be generally transparent to the near infrared wavelengths produced by the phosphor of the light-converting layer 530. The secondary emitter layer 534 may be a plate, which may be planar or may be shaped and used as infrared optical elements. [0064] In some embodiments, other structures may be disposed between the LED die 510 and the secondary emitter layer 534. For example, a dichromatic mirror that is transparent to the light emitted by the LED die 510 and the light-converting layer 530 may be used to reflect heat of the secondary emitter layer 534 towards the secondary emitter layer 534.

[0065] FIGS. 7A-7D illustrate example lighting structures 700a, 700b, 700c, 700d according to some embodiments. In FIG. 7A, a PCB 702 may be provided on which other structures are disposed. The PCB 702 may include at least a metal core layer 702a, an isolation layer 702b (insulator), and a conductive (e.g., copper) layer 702c. A submount 704 may be disposed on the PCB 702. Connections in the submount 704 may be electrically coupled to the PCB 702 through solder (as best shown in the embodiment of FIG. 7D). An LED 706 may be disposed on the submount 704. A light converting layer 708 may be disposed on the LED 706. The light converting layer 708 may contain phosphor particles. A secondary emitter layer 710 may be disposed above the LED 706 and light converting layer 708. The secondary emitter layer 710 may be supported by posts 712 that rest on the submount 704. In some embodiments, a coating of amorphous (black) Silicon may be formed on the surface of the secondary emitter layer 710 facing the LED 706.

[0066] The temperature and flux of the secondary emitter layer 710 may be tuned by the size and shape of the secondary emitter layer 710, in addition to driving of the LED 706. In some embodiments, as shown in FIG. 7A, the area of the secondary emitter layer 710 may be smaller than that of the LED 706. [0067] The lighting structure 700b of FIG. 7B is similar to the lighting structure 700a of FIG. 7A. However, the secondary emitter layer 710a in the lighting structure 700b of FIG. 7B contains dimples 710b. The dimples 710b may be concave recesses that are etched (e.g., wet chemically etched) or otherwise mechanically formed in the secondary emitter layer 710a to increase a surface area of the secondary emitter layer 710a or may include convex protrusions that extend from a planar portion of the surface of the secondary emitter layer 710a (i.e., the secondary emitter layer 710a comprises a first planar surface facing the LED 706 and a second surface containing dimples that are at a different distance from the LED 706 than a planar portion of the second surface). The dimples 710b may be used to increase a top area of the secondary emitter layer 710a used for IR transmittance over the bottom area that faces the light converting layer 708 and the LED 706 to increase the emission at the top area and reduce the emission transmitted back to the light converting layer 708 and the LED 706 as the amount of radiation is proportional to the emitting area. Features other than the dimples 710b shown may be used to increase the surface area of the secondary emitter layer 710a in a desired direction.

[0068] In some embodiments, as shown in FIG. 7B, the area of the secondary emitter layer 710a may be about the same as that that of the LED 706. In other embodiments, the area of the secondary emitter layer 710, 710a may be larger than that of the LED 706.

[0069] The embodiments of FIG. 7A and FIG. 7B illustrate that the secondary emitter layer 710, 710a is supported by posts 712, which may be formed from quartz or another substantially thermally non-conductive material. The posts 712 may rest on the submount 704, as shown in FIG. 7A, or on the PCB 702, as shown in FIG. 7B. In other embodiments, such as shown in FIG. 7C, the secondary emitter layer 710, 710a may be supported by a solid structure, such as a solid layer or a ring 712a in which a band of solid material supports comers or edges of the secondary emitter layer 710, 710a while the middle of the material remains empty (e.g., an air gap is present between the secondary emitter layer 710, 710a and the LED 706). Such a ring may be of any shape, e.g., circular or polygonal (such as rectangular). The ring 712a may rest on the submount 704, or as shown in FIG. 7C on the PCB 702.

[0070] The embodiments of FIG. 7A and FIG. 7B illustrate that the secondary emitter layer 710, 710a is supported by posts 712, which may be formed from quartz or another thermally non-conductive material. In FIG. 7D, the posts 712 may rest on the PCB 702. Conductive traces on the PCB 702 may be coupled to conductive traces or vias of the submount 704 via solder 704a. [0071] FIG. 8 illustrates an example system, according to some embodiments. As above, some of the elements shown in the system 800 may not be present, while other additional elements may be disposed in the system 800. The system 800 may include a controller 802 that controls illumination using an illumination structure 810 that contains one or more LED structures 812, each containing one or more LEDs 814.

[0072] In some embodiments, some or all of the components described as the controller 802 may be disposed on a backplane or support such as, for example, a complementary metal oxide semiconductor (CMOS) backplane. The controller 802 may be coupled to or include one or more processors 804. The one or more processors 804 may receive information from a remote (e.g., user) unit to control a generator 806a, for example, controlling analog signals or PWM duty cycles and/or turn-on times for causing the system 800 to drive the one or more LED structures 812.

[0073] The controller 802 may include, among others, one or more PCBs, drivers to drive the LEDs using one or more channels, and WiFi or other communication modules to communicate with a remote (user) device. The controller 802 may be split into different components that are disposed in one or more locations within the system 800.

[0074] The system 800 can be packaged in a single housing and include a submount, PCB, and/or CMOS backplane for powering and controlling light production by the LEDs. The PCB supporting the LED array may include electrical vias, heat sinks, ground planes, electrical traces, and flip chip or other mounting systems. The submount or PCB may be formed of any suitable material, such as ceramic, silicon, aluminum, etc. If the submount material is conductive, an insulating layer may be formed over the substrate material, and a metal electrode pattern formed over the insulating layer. The submount can act as a mechanical support, providing an electrical interface between electrodes on the LED array and a power supply, and also provide heat sink functionality.

[0075] The generator 806a may be controlled by the processor 804 and may produce driving signals. The generator 806a may be coupled to a driver 806b to drive the illumination structure 810 so that the one or more LED structures 812 provide the infrared (and perhaps visible) light described above. As shown, the one or more LED structures 812 may include, for each LED structure 812 or LED 814, a PWM switch, and a current source.

[0076] The system 800 may further include a power supply 820. In some embodiments, the power supply 820 may be a battery that produces power for the controller 802.

[0077] FIG. 9 illustrates a top plan view of an example array suitable for implementing embodiments described herein. The example hybridized device illustrated in FIG. 9 includes an LED die 910 that includes LEDs 912 in the LED structure that contains the light-converting layer and the secondary emitter layer, such as those described herein. Each LED 912 (or group of LEDs) of the array may correspond to a projector picture element or projector pixel for a spectroscopic device, for example. Suitable hybridized devices may include monolithic LED arrays, micro LED arrays, etc. Each LED 912 in LED die 910 may be individually addressable. Alternatively, groups or subsets of LEDs 912 may be addressable. Each LED 912 may have a size in the range of micrometers (i.e., between 1 micrometer (pm) and 100 pm). For example, LED 912 may have dimensions of approximately (within 10 pm by 10 pm) 40 pm by 40 pm in some embodiments. An LED 912 may have a lateral dimension of less than 100 pm in some embodiments.

[0078] LEDs 912 may be arranged as a matrix comprising one or more rows and one or more columns to define a rectangle. In other embodiments, LEDs 912 may be arranged to define other shapes. Each LED 912 in the LED die 910 may encompass from several (e.g., 9) LEDs to a much larger number (e.g., hundreds) of LEDs. In some embodiments, the height dimension of an array including the LEDs 912, their supporting substrate and electrical traces, and associated micro-optics may be less than 5 millimeters.

[0079] An exploded view of a 3x3 sub-array 916 of LEDs 912 included in LED die 910 is also shown in FIG. 9. Sub-array 916 may include LEDs 912, each defined by a width wl. In some example embodiments, width wl can be approximately 100pm or less (e.g., 40pm). As shown in the sub-array 916, lanes 914 may be defined extending horizontally and vertically to define rows and columns of LEDs 912. Lanes 914 between the LEDs 912 may have a width, w2, wide. In some embodiments, the width w2 may be approximately 20pm or less (e.g., 5pm). In some embodiments, the width w2 may be as small as 1 gm. The lanes 914 may provide an air gap between adjacent emitters or may contain other material. A distance dl from the center of one LED 912 to the center of an adjacent LED 912 may be approximately 120pm or less (e.g., 45pm). It will be understood that the widths and distances provided herein are examples of one of many possible embodiments in which widths and/or other dimensions may vary. [0080] In some example embodiments, lanes 914 may be defined by a width w2 that can be approximately 20pm or less (e.g., 5pm). In some example embodiments, width w2 can be as small as 1pm. Lanes 914 can serve to provide an air gap between adjacent LEDs 912 and may contain material other than light emitting material. In some example embodiments, a distance dl from the center of one LED 912 to the center of an adjacent LED 912 can be approximately 120pm or less (e.g., 45pm). It will be understood that the LED and lane widths and distances between LEDs are intended as examples. Persons of ordinary skill reading the disclosure herein will appreciate a range of widths and/or dimensions will be suitable for various implementations, and those embodiments will fall within the scope of the disclosure.

[0081] For the convenience of illustration, LED 912 that are included in the LED die 910 are depicted herein as having a rectangular shape. However, as persons of ordinary skill will appreciate, a variety of other emitter shapes would be suitable for implementing the LED 912 and LED die 910 in various applications, and those would fall within the scope of the embodiments described herein. Likewise, LED die 910 is depicted in FIG. 9 as a symmetric matrix of LEDs 912. However, various other implementations of the LED die 910 may be suitable for implementing embodiments described herein, depending on application and design considerations. For example, in some implementations, LED die 910 can comprise a linear array of LEDs 912, and in other implementations a rectangular array of LEDs 912. In some implementations, the LED die 910 can comprise a symmetric or asymmetric matrix of LEDs 912. LED die 910 can comprise an array or matrix defined by a dimension or order that differs from the array dimensions or orders depicted herein. [0082] For example, in some practical applications, the LED die 910 depicted in FIG. 9 may include LEDs 912 in asymmetric or symmetric arrangements in a wide range of array dimensions and orders (e.g., a symmetric matrix or a non-symmetric matrix). For example, in some practical applications, two or more LED dies 910 can be stacked such that LEDs 912 are arranged to define rows and columns that extend in three spatial directions or dimensions. It will also be understood that the LED die 910 can itself be a subarray of a larger array (not shown) of LEDs 912.

[0083] LED die 910 may have a surface area of 90 mm² or greater and may require significant power to drive the array. In some applications, this power can be as much as 60 watts or more. The LED die 910 may include several, dozens, hundreds, thousands, or even millions of LEDs or emitters arranged within a centimeter-scale area substrate or smaller. A LED may include an array of individual emitters provided on a substrate or may be a single silicon wafer, or die partially or fully divided into light-emitting segments that form the LEDs 912. In some embodiments, the emitters may have distinct nonwhite colors.

[0084] FIG. 10 illustrates an example method of fabricating an illumination device, according to some embodiments. Not all of the operations may be undertaken in the method 1000, and/or additional operations may be present. The operations may occur in a different order from that indicated in FIG. 10

[0085] At operation 1002, the LED may be fabricated. The LED may include an n-type semiconductor layer, a p-type semiconductor layer, and an active region between the n-type semiconductor layer and the p-type semiconductor layer. The active layer may include, for example, one or more quantum wells designed to emit light at a particular wavelength. For example, the semiconductor may be formed from GaN and may, in operation, emit blue light.

[0086] At operation 1004, a phosphor-containing layer may be deposited on the LED. The phosphor-containing layer may be designed to absorb a small portion (e.g., about 5 to about 10%) of the light from the LED and emit light in a near-infrared wavelength range of between about 1 pm and about 2.5 pm. [0087] At operation 1006, a secondary emitter layer may be separated from the LED structure containing the LED and the phosphor layer. The secondary emitter layer may be separated from the LED structure using a non- conductive structure at the edges or comers, or via a solid layer. The secondary emitter layer may be a layer formed from Si, for example. The separation may be designed such that during operation the secondary emitter layer absorbs most or all of the blue light from the LED that remains unconverted by the phosphorcontaining layer, heats up (e.g., to a range between about 450 °C and about 750 °C), and emits radiation at a short/mid-infrared range of around or above about 2.5 pm. The secondary emitter layer may be substantially transparent to the light in the near-infrared wavelength range emitted by the phosphor-containing layer. The overall device may thus emit light in the near-infrared and midinfrared wavelength range, which can be used for spectroscopic applications, for example.

[0088] Additionally, the transient response of the secondary emitter layer (which may be a slab of silicon or another material) can be used to provide spectroscopic applications. During heat-up (and cool-down) the peak wavelength of the blackbody radiator shifts; the transmittance properties also change. The integrated dose may be spectroscopically analyzed or, depending on the particular spectroscopic task, an optimized emission at a certain moment in time can be targeted for the analysis.

[0089] The response of the secondary emitter layer in the system may be calibrated in-situ prior to measuring and analyzing a particular sample. The calibration may be performed by measuring the resistance of the secondary emitter layer to determine the temperature of the secondary emitter layer.

[0090] While only certain features of the system and method have been illustrated and described herein, many modifications and changes will occur to those skilled in the art upon reading and understanding the disclosed subject matter. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes. Method operations may be performed substantially simultaneously or in a different order.

[0091] Examples [0092] Example 1 is an illumination device comprising: a light emitting diode (LED) structure configured to emit light in a first wavelength range; and a plate separated from the LED structure, the plate configured to absorb at least some of the light emitted by the LED structure and to emit blackbody radiation in a second wavelength range, the blackbody radiation caused by an elevated temperature of the plate from absorption of the light from the LED structure by the plate, the second wavelength range having a peak emission at a wavelength larger than the first wavelength range.

[0093] In Example 2, the subject matter of Example 1 includes, wherein the LED structure includes: a semiconductor active region configured to emit blue light as the light of the first wavelength range; and a phosphor layer configured to absorb a portion of the blue light and to emit light in a third wavelength range between the first wavelength range and the second wavelength range.

[0094] In Example 3, the subject matter of Example 2 includes, wherein the phosphor layer comprises a sintered aluminum oxide (A12O3) layer with phosphor dopants.

[0095] In Example 4, the subject matter of Examples 2-3 includes, wherein the plate is substantially transparent to the light in the third wavelength range.

[0096] In Example 5, the subject matter of Examples 1-4 includes, wherein the plate comprises an infrared transparent filler that is configured to heat the plate in response to absorption of the light in the first wavelength range and to emit light in a mid-infrared range.

[0097] In Example 6, the subject matter of Example 5 includes, wherein the infrared transparent filler includes silicon.

[0098] In Example 7, the subject matter of Examples 1-6 includes, wherein the plate includes undoped silicon that is configured to heat the plate in response to absorption of the light in the first wavelength range and to emit light in a mid-infrared range.

[0099] In Example 8, the subject matter of Examples 1-7 includes, wherein the plate comprises doped silicon that is configured to heat the plate in response to absorption of the light in the first wavelength range and emit light in a mid-infrared range.

[00100] In Example 9, the subject matter of Examples 1-8 includes, wherein the illumination device is configured to simultaneously emit light in the second wavelength range and light in a third wavelength range, the peak of the second wavelength range being between about 3 pm and about 5 pm and the third wavelength range being between about 1.6 pm and about 2.1 pm.

[00101] In Example 10, the subject matter of Examples 1-9 includes, non- conductive supports configured to separate the LED structure and the plate, the LED structure and the plate separated by an air gap between the non-conductive supports.

[00102] In Example 11, the subject matter of Examples 1-10 includes a non-conductive layer configured to separate the LED structure and the plate. [00103] In Example 12, the subject matter of Examples 1-11 includes a lens having a first surface on which the plate is mounted, the light in the first wavelength range configured to impinge on a second surface of the lens that is opposite the first surface of the lens.

[00104] In Example 13, the subject matter of Examples 1-12 includes, wherein the plate comprises a first planar surface facing the LED structure and a second surface containing dimples that are at a different distance from the LED structure than a planar portion of the second surface.

[00105] In Example 14, the subject matter of Examples 1-13 includes a dichromatic mirror, the dichromatic mirror being a structure disposed between the LED structure and the plate or being a coating on the plate, the dichromatic mirror transparent to the light in the first wavelength range and configured to reflect light in the second wavelength range back towards the plate.

[00106] In Example 15, the subject matter of Examples 1-14 includes another LED structure configured to emit light in a third wavelength range between the first wavelength range and the peak emission of the second wavelength range, the plate configured to absorb a portion of the light emitted by the other LED structure and emit the blackbody radiation in the second wavelength range. [00107] In Example 16, the subject matter of Examples 1-15 includes, wherein a surface area of the plate is larger than an area of the LED structure and entirely overlaps the area of the LED structure.

[00108] Example 17 is an electronic system comprising: an illumination device comprising: a light emitting diode (LED) structure configured to emit light in a first wavelength range; and a plate separated from the LED structure, the plate configured to absorb at least some of the light emitted by the LED structure and to emit blackbody radiation in a second wavelength range, the blackbody radiation caused by an elevated temperature of the plate from absorption of the light from the LED structure by the plate, the second wavelength range having a peak emission at a wavelength larger than the first wavelength range; and at least one sensor configured to detect light that is dependent on the light of the first wavelength range and the light of the second wavelength range emitted by the illumination device.

[00109] In Example 18, the subject matter of Example 17 includes, wherein the LED structure includes: a semiconductor active region configured to emit blue light as the light of the first wavelength range; and a phosphor layer configured to absorb a portion of the blue light and emit light in a third wavelength range between the first wavelength range and the second wavelength range.

[00110] In Example 19, the subject matter of Example 18 includes wherein the phosphor layer comprises a sintered aluminum oxide (A12O3) layer with phosphor dopants.

[00111] In Example 20, the subject matter of Examples 18-19 includes, wherein the plate is substantially transparent to the light in the third wavelength range.

[00112] In Example 21, the subject matter of Examples 17-20 includes, wherein the plate comprises an infrared transparent filler that is configured to heat the plate in response to absorption of the light in the first wavelength range and emit light in a mid-infrared range.

[00113] In Example 22, the subject matter of Example 21 includes, wherein the infrared transparent filler comprises silicon. [00114] In Example 23, the subject matter of Examples 17-22 includes, wherein the plate comprises undoped silicon that is configured to heat the plate in response to absorption of the light in the first wavelength range and emit light in a mid-infrared range.

[00115] In Example 24, the subject matter of Examples 17-23 includes, wherein the plate comprises doped silicon that is configured to heat the plate in response to absorption of the light in the first wavelength range and emit light in a mid-infrared range.

[00116] In Example 25, the subject matter of Examples 17-24 includes, wherein the illumination device is configured to simultaneously emit light in the second wavelength range and light in a third wavelength range, the peak of the second wavelength range being between about 3 pm and about 5 pm and the third wavelength range being between about 1.6 pm and about 2.1 pm.

[00117] In Example 26, the subject matter of Examples 17-25 includes, non-conductive supports configured to separate the LED structure and the plate, the LED structure and the plate separated by an air gap between the non- conductive supports.

[00118] In Example 27, the subject matter of Examples 17-26 includes a non-conductive layer configured to separate the LED structure and the plate.

[00119] In Example 28, the subject matter of Examples 17-27 includes a lens having a first surface on which the plate is mounted, the light in the first wavelength range configured to impinge on a second surface of the lens that is opposite the first surface of the lens.

[00120] In Example 29, the subject matter of Example 28 includes a printed circuit board (PCB) on which the LED structure and the at least one sensor are mounted.

[00121] In Example 30, the subject matter of Example 29 includes a controller mounted on the PCB, the controller configured to control a pump intensity of the LED structure to control heating of the plate and emission of the light of the second wavelength range.

[00122] In Example 31, the subject matter of Examples 17-30 includes, wherein the plate comprises a first planar surface facing the LED structure and a second surface containing dimples that are at a different distance from the LED structure than a planar portion of the second surface.

[00123] In Example 32, the subject matter of Examples 17-31 includes a dichromatic mirror, the dichromatic mirror being a structure disposed between the LED structure and the plate or being a coating on the plate, the dichromatic mirror transparent to the light in the first wavelength range and configured to reflect light in the second wavelength range back towards the plate.

[00124] In Example 33, the subject matter of Examples 17-32 includes another LED structure configured to emit light in a third wavelength range between the first wavelength range and the peak emission of the second wavelength range, the plate configured to absorb a portion of the light emitted by the other LED structure and emit the blackbody radiation in the second wavelength range.

[00125] In Example 34, the subject matter of Examples 17-33 includes, wherein: the electronic system is a portable spectroscopic device, and the electronic system further includes a processor configured to provide an element analysis of a sample illuminated by the illumination device based on an output of the at least one sensor.

[00126] In Example 35, the subject matter of Examples 17-34 includes, wherein: the electronic system is a portable spectroscopic device, and the electronic system further includes a processor configured to determine a concentration of at least one gas based on an output of the at least one sensor. [00127] In Example 36, the subject matter of Examples 17-35 includes, wherein a surface area of the plate is larger than an area of the LED structure and entirely overlaps the area of the LED structure.

[00128] Example 37 is a method of fabricating an electronic device, the method comprising: disposing a light emitting diode (LED) structure on a mounting structure; positioning a plate to be separated from the LED structure such that, during operation, the LED structure generates light in a first wavelength range that is partially absorbed by the plate, which heats up to an elevated temperature and emits blackbody radiation in a second wavelength range caused by heating the plate to the elevated temperature, the second wavelength range having a peak emission greater than the first wavelength range; and disposing at least one sensor to detect light that is dependent on the light of the first wavelength range and the light of the second wavelength range emitted by the electronic device.

[00129] In Example 38, the subject matter of Example 37 includes, wherein the LED structure comprises: a semiconductor active region configured to emit blue light as the light of the first wavelength range; and a phosphor layer configured to absorb a portion of the blue light and emit light in a third wavelength range between the first wavelength range and the second wavelength range.

[00130] In Example 39, the subject matter of Example 38 includes, wherein the phosphor layer comprises a sintered aluminum oxide (A12O3) layer with phosphor dopants.

[00131] In Example 40, the subject matter of Examples 38-39 includes, wherein the plate is substantially transparent to the light in the third wavelength range.

[00132] In Example 41, the subject matter of Examples 37-40 includes, wherein the plate comprises an infrared transparent filler that heats the plate in response to absorption of the light in the first wavelength range and emits light in a mid-infrared range.

[00133] In Example 42, the subject matter of Example 41 includes, wherein the infrared transparent filler comprises silicon.

[00134] In Example 43, the subject matter of Examples 37-42 includes, wherein the plate comprises silicon that heats the plate in response to absorption of the light in the first wavelength range and emits light in a mid-infrared range. [00135] In Example 44, the subject matter of Examples 37-43 includes, wherein during operation the light in the second wavelength range and light in a third wavelength range are simultaneously emitted, the peak of the second wavelength range being between about 3 pm and about 5 pm and the third wavelength range being between about 1.6 pm and about 2.1 pm.

[00136] In Example 45, the subject matter of Examples 37-44 includes, using non-conductive supports and an air gap between the non-conductive supports to separate the LED structure and the plate. [00137] In Example 46, the subject matter of Examples 37-45 includes, using a non-conductive layer to separate the LED structure and the plate.

[00138] In Example 47, the subject matter of Examples 37-46 includes adjusting the light in the first wavelength range using a lens having a first surface on which the plate is mounted, the light in the first wavelength range impinging on a second surface of the lens that is opposite the first surface of the lens.

[00139] In Example 48, the subject matter of Examples 37-47 includes, mounting the LED structure and the at least one sensor on a printed circuit board (PCB), the at least one sensor detecting the light of the first wavelength range and the light of the second wavelength range.

[00140] In Example 49, the subject matter of Example 48 includes, mounting a controller on the PCB, the controller configured to control a pump intensity of the LED structure to control heating of the plate and emission of the light of the second wavelength range.

[00141] In Example 50, the subject matter of Examples 37-49 includes, wherein the plate comprises a planar surface containing dimples that extend towards the LED structure.

[00142] In Example 51, the subject matter of Examples 37-50 includes, disposing a dichromatic mirror between the LED structure and the plate, the dichromatic mirror transparent to the light in the first wavelength range and reflecting heat towards the plate.

[00143] In Example 52, the subject matter of Examples 37-51 includes, during operation using another LED structure to emit light in a third wavelength range between the first wavelength range and the peak emission of the second wavelength range, the plate configured to absorb a portion of the light emitted by the other LED structure and emit the blackbody radiation in the second wavelength range.

[00144] In Example 53, the subject matter of Examples 37-52 includes, wherein: the electronic device is a portable spectroscopic device, and the method further comprises providing an element analysis of a sample illuminated by the spectroscopic device based on an output of the at least one sensor. [00145] In Example 54, the subject matter of Examples 37-53 includes, wherein: the electronic device is a portable spectroscopic device, and the method further comprises during operation determining a concentration of at least one gas based on an output of the at least one sensor.

[00146] In Example 55, the subject matter of Examples 37-54 includes, wherein a surface area of the plate is larger than an area of the LED structure and entirely overlaps the area of the LED structure.

[00147] In Example 56, the subject matter of Examples 37-55 includes, detecting the light of the second wavelength range emitted by the electronic device during at least one of heating and cooling of the plate in response, a peak emission shifting in time dependent on the heating and cooling of the plate. [00148] Example 57 is at least one machine-readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement of any of Examples 1-56.

[00149] Example 58 is an apparatus comprising means to implement of any of Examples 1-56.

[00150] Example 59 is a system to implement of any of Examples 1-56.

[00151] Example 60 is a method to implement of any of Examples 1-56.

[00152] Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof show, by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. [00153] The subject matter may be referred to herein, individually and/or collectively, by the term “embodiment” merely for convenience and without intending to voluntarily limit the scope of this application to any single inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. [00154] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In this document, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, UE, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. As indicated herein, although the term “a” is used herein, one or more of the associated elements may be used in different embodiments. For example, the term “a processor” configured to carry out specific operations includes both a single processor configured to carry out all of the operations as well as multiple processors individually configured to carry out some or all of the operations (which may overlap) such that the combination of processors carry out all of the operations. Note that the term “about x” and similar terms (e.g., substantially) as used herein may be understood to be within 10% of x or otherwise within a range known to one of skill in the art to be within tolerance of the quantity or quality described, unless otherwise indicated. [00155] The Abstract of the Disclosure is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it may be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

Claims

WHAT IS CLAIMED IS:

1. An illumination device comprising: a light emitting diode (LED) structure configured to emit light in a first wavelength range; and a plate separated from the LED structure, the plate configured to absorb at least some of the light emitted by the LED structure and to emit blackbody radiation in a second wavelength range, the blackbody radiation caused by an elevated temperature of the plate from absorption of the light from the LED structure by the plate, the second wavelength range having a peak emission at a wavelength larger than the first wavelength range.

2. The illumination device of claim 1, wherein the LED structure includes: a semiconductor active region configured to emit blue light as the light of the first wavelength range; and a phosphor layer configured to absorb a portion of the blue light and to emit light in a third wavelength range between the first wavelength range and the second wavelength range.

3. The illumination device of claim 2, wherein the phosphor layer includes a sintered aluminum oxide (A12O3) layer with phosphor dopants.

4. The illumination device of claim 2 or 3, wherein the plate is substantially transparent to the light in the third wavelength range.

5. The illumination device of any of claims 1-4, wherein the plate comprises an infrared transparent filler that is configured to heat the plate in response to absorption of the light in the first wavelength range and to emit light in a mid-infrared range.

6. The illumination device of any of claims 1-5, wherein the plate includes at least one of doped silicon or undoped silicon that is configured to heat the plate in response to absorption of the light in the first wavelength range and to emit light in a mid-infrared range.

7. The illumination device of any of claims 1-6, further comprising non- conductive supports configured to separate the LED structure and the plate, the LED structure and the plate separated by an air gap between the non-conductive supports.

8. The illumination device of any of claims 1-7, further comprising a non- conductive layer configured to separate the LED structure and the plate.

9. The illumination device of any of claims 1-8, further comprising a lens having a first surface on which the plate is mounted, the light in the first wavelength range configured to impinge on a second surface of the lens that is opposite the first surface of the lens.

10. The illumination device of any of claims 1-9, wherein the plate comprises a first planar surface facing the LED structure and a second surface containing dimples that are at a different distance from the LED structure than a planar portion of the second surface.

11. The illumination device of any of claims 1-10, further comprising a dichromatic mirror, the dichromatic mirror being a structure disposed between the LED structure and the plate or being a coating on the plate, the dichromatic mirror transparent to the light in the first wavelength range and configured to reflect light in the second wavelength range back towards the plate.

12. The illumination device of any of claims 1-11, further comprising another LED structure configured to emit light in a third wavelength range between the first wavelength range and the peak emission of the second wavelength range, the plate configured to absorb a portion of the light emitted by the other LED structure and emit the blackbody radiation in the second wavelength range.

13. An electronic system comprising: an illumination device comprising: a light emitting diode (LED) structure configured to emit light in a first wavelength range; and a plate separated from the LED structure, the plate configured to absorb at least some of the light emitted by the LED structure and to emit blackbody radiation in a second wavelength range, the blackbody radiation caused by an elevated temperature of the plate from absorption of the light from the LED structure by the plate, the second wavelength range having a peak emission at a wavelength larger than the first wavelength range; and at least one sensor configured to detect light that is dependent on the light of the first wavelength range and the light of the second wavelength range emitted by the illumination device.

14. The electronic system of claim 13, wherein the plate comprises an infrared transparent filler that is configured to heat the plate in response to absorption of the light in the first wavelength range to emit light in a midinfrared range.

15. The electronic system of claim 13 or 14, further comprising at least one of: non-conductive supports configured to separate the LED structure and the plate, the LED structure and the plate separated by an air gap between the non-conductive support, or a non-conductive layer configured to separate the LED structure and the plate.

16. The electronic system of claim 15, further comprising: a printed circuit board (PCB) on which the LED structure and the at least one sensor are mounted; and a controller mounted on the PCB, the controller configured to control a pump intensity of the LED structure to control heating of the plate and emission of the light of the second wavelength range.

17. The electronic system of any of claims 13-16, wherein: the electronic system is a portable spectroscopic device, and the electronic system further includes a processor configured to at least one of provide an element analysis of a sample illuminated by the illumination device based on an output of the at least one sensor, or determine a concentration of at least one gas based on an output of the at least one sensor.

18. The electronic system of any of claims 13-17, wherein the plate comprises a first planar surface facing the LED structure and a second surface containing dimples that are at a different distance from the LED structure than a planar portion of the second surface.

19. A method of fabricating an electronic device, the method comprising: disposing a light emitting diode (LED) structure on a mounting structure; positioning a plate to be separated from the LED structure such that, during operation, the LED structure generates light in a first wavelength range that is partially absorbed by the plate, which heats up to an elevated temperature and emits blackbody radiation in a second wavelength range caused by heating the plate to the elevated temperature, the second wavelength range having a peak emission greater than the first wavelength range; and disposing at least one sensor to detect light that is dependent on the light of the first wavelength range and the light of the second wavelength range emitted by the electronic device.

20. The method of claim 19, further comprising detecting the light of the second wavelength range emitted by the electronic device during at least one of heating and cooling of the plate in response, a peak emission shifting in time dependent on the heating and cooling of the plate.