Multiple emission LED die and spectrometry

Abstract

A monolithic LED IC die can include multiple emission regions independently operable by applying independent electrical input signals, such as to independently control light output from different individual ones of the multiple emission regions. Optics can include different spectral filters applied to the different light outputs from the different individual ones of the multiple emission regions, such as to define different spectral bands output by the different spectral filters. These different spectral bands can be differently encoded, and the encoded light can be used for enhanced spectroscopy. Additionally or alternatively, the different individual ones of the multiple emission regions can be selectively energized, such as to provide a tunable light source via the different spectral bands output by the optics. The monolithic LED IC die with the multiple emission regions can make the optics more compact, such as for a wearable or other compact device for spectroscopic measurement or analysis.

Description

[0001] MULTIPLE EMISSION LED DIE AND SPECTROMETRY

[0002] CLAIM OF PRIORITY

[0003] This patent application claims the benefit of priority of Deliwala U.S.

[0004] Provisional Patent Application Serial Number 63 / 726,143, filed November 27, 2024, entitled MULTI-EMISSION LED DIE AND SPECTROMETRY (Attorney Docket No. 5712.007PRV), which is hereby incorporated by reference herein in its entirety.

[0005] CROSS-REFERENCE TO RELATED PATENT DOCUMENTS

[0006] This patent application is related to U.S. Provisional Patent Application Serial Number 63 / 200,241 entitled CODED LIGHT FOR TARGET IMAGING OR ANALYSIS, filed February 24, 2021, naming Shrenik Deliwala as inventor, which application is hereby incorporated herein by reference in its entirety.

[0007] This document also incorporates by reference each of the following:

[0008] 1. U.S. Patent No. 11,704,886;

[0009] 2. U.S. Patent No. 18,045,701; and

[0010] 3. International Patent Application Serial No. PCT / US2022 / 017503, filed February 23, 2022, which claims the benefit of priority to U.S. Provisional Application Serial Nos. 63 / 262,370, filed October 11, 2021; and 63 / 202,325, filed June 7, 2021; and 63 / 200,241, filed February 24, 2021, each of which are incorporated by reference herein in their entirety;

[0011] 4. U.S. Patent Application No. 18 / 886,840 entitled MULTIPLE INPUT SPECTROMETER, filed on September 16, 2024 (Attorney Docket No. 5712.005US1); and

[0012] 5. U.S. Patent Application No. 18 / 929,298 entitled ELECTRONIC ARCHITECTURE FOR CODED LIGHT TARGET ANALYSIS, filed on October 28, 2024 (Attorney Docket No. 5712.006US1). TECHNICAL FIELD

[0013] This document pertains generally, but not by way of limitation, to systems, devices, and methods employing Light Emitting Diodes (LEDs) such as for using coded light, such as for target imaging or analysis of a fixed target, or of moving target, for example, for measurement of chemical properties or composition of gases, liquids, and solids.

[0014] BACKGROUND

[0015] Properties of gases, liquids, and solids can be measured spectroscopically, which can involve using LEDs to generate illumination light for performing the spectroscopy on the target analyte or substance of interest or under test.

[0016] SUMMARY

[0017] In the above-incorporated patent documents relating to encoding and decoding light for spectroscopy and other applications, an LED based system is described, in which multiple, individual LEDs are concurrently modulated for encoding the light. For spectroscopic purposes, a narrower slice of the spectrum emitted from each of the modulated LEDs is selected by the optical system and aggregated into a combined coded beam for encoded light illumination. For an individual one (or for each individual one) of the LEDs, one or more narrower slices of the particular individual LED’s encoded illumination output spectrum can be selected. These one or more narrower slices from one or more individual LED’s output spectrum or spectra can then be aggregated into a combined coded beam for encoded light illumination, such as for spectroscopy of a target or other purpose.

[0018] In certain cases, the spectroscopic frequency spectrum of interest of the target is such that the entire spectrum of interest (e.g., such as corresponding to molecular spectra of gases) is covered by an appropriate spectrum of a particular individual LED. In such a case, multiple LEDs of the same kind may still be needed, e.g., multiple LEDs having spectra that are differently sliced to respectively provide light sources for performing coded light spectroscopy.

[0019] A significant simplifying improvement of the optical design and packaging can be accomplished by providing a single individual monolithic LED die, which can provide multiple electrical connections and multiple corresponding optical outputs (also referred to as “emission regions”). . The illumination corresponding to the multiple optical outputs or “emission regions” can then respectively be sliced into different spectral slices, such as for use in performing coded light spectroscopy. This approach can help provide multiple benefits: (a) a single LED die can be placed during assembly, as opposed to needing to pick-and-place multiple LED die with definite corresponding spatial locations and spatial accuracy process requirements, (b) the relative position of the optical outputs are lithographically defined, and therefore can achieve the accuracy available for the semiconductor manufacturing process, as opposed to a lower relative accuracy associated with a die pick-and-place process, (c) the temperature of the entire LED monolithic integrated circuit die will be will be the same or very similar, thereby making temperature-related relative changes in spectra easier to model or otherwise account for, and (d) the present approach can employ fewer LED die and assembly steps — and this can also be the case even when making a broadband spectroscopic device that needs multiple LEDs of different kinds to provide associated different frequency bands to cover the entire particular spectroscopic frequency range of interest of a particular target. This can help significantly lower the cost of the spectroscopic device, can help add to the manufacturing precision, and can help improve the performance of the spectroscopic or other system.

[0020] As explained herein, the accuracy of spectral slicing and wavelength centering in a dispersive filtering system or in a system employing a linear variable filter depends on the relative accuracy with which emission regions can be located. By having semiconductor processing lithography define multiple optical emissions regions on a shared LED integrated circuit die, the repeatability and precision of the manufactured system can be increased. Additionally, the present approach can help facilitate a push towards compact spectroscopic systems -such as one inside a smartwatch or other wearable device. Such a compact system can benefit from employing emission regions that are closer than the ability to electrical pitch for electrical connections (e.g., pitch between adjacent bonding pads) and / or integrated circuit die pick-and- place precision that is less than 10 microns. Either or both of these benefits can be achieved by patterning the LED die with multiple emission regions, such as explained herein.

[0021] This summary / overview is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0024] FIG. 1A: shows a comparative LED die diced from a wafer.

[0025] FIG. IB: shows examples of spectra of comparative LEDs of different wavelengths.

[0026] FIG. 1C: is a block diagram of portions of an active optical illumination system for spectroscopic measurement or multi -wavelength measurement, such as of tissue, another biological substance, or another sample.

[0027] FIG. 2: shows an example of portions of a LED-based coded light approach for providing coded illumination for spectroscopic measurement, such as which can include or be combined with the present approach.

[0028] FIGS. 3A, 3B, 3C, and 3D: together show aspects of an example of a comparative approach using multiple LEDs of the same type on corresponding individual LED dies that are picked-and-placed and arranged or assembled to produce a common modulated output for an example of an oxygen sensor.

[0029] FIGS. 4A, 4B, 4C, and 4D: together show aspects of an example of the present approach using multiple LEDs of the same type on a shared monolithic die with corresponding spectral output regions that can be defined using semiconductor processing, such that these various corresponding more closely- spaced spectral output regions can be arranged to produce a common modulated output for an improved example of an oxygen sensor.

[0030] FIGS. 5A, 5B, 5C, and 5D together show portions of another example, such as in which multi-gas detection with seven emission regions to detect alcohol, water vapor, and CO2 sensor can be approached using one or more monolithic die, each with multiple different spectral emission output regions.

[0031] FIGS. 6 A, 6B, and 6C: together show an approach of how to configure a multi-emission LED die so as to help eliminate the drift that may exist between the two measurements corresponding to (1) a reference path and (2) a measurement path.

[0032] FIGS. 7A, 7B, and 7C: together show examples of a monolithic LED die with multiple individually controlled spectral output emissions region; FIG. 7A shows an example of a staggered row of spectral output emission regions to help increase spectral resolution; and FIG. 7B shows an example of a flip-chip LED die in which emission occurs through the substrate with patterned metallization on the back to allow light to escape.

[0033] FIG. 8 shows an example of a broadband spectrometer of the type shown in FIG. 2, but in which in which multiple, multiple output LED die can be used to provide SWIR measurement; FIG. 8also shows how different slices of spectra are selected from the same die.

[0034] FIGS. 9A, 9B, 9C, 9D, and 9E: together show various patterns of multiple emission regions from a single LED die. FIGS. 9A, 9B, and 9C all show various types of one dimensional patterns with single row of individually addressable emission regions while FIGS. 9D and 9E show dual rows of emission regions.

[0035] FIGS. 10A and 10B show an example of portions of a compact SpO2 sensor that can use orange / green spectral bands of hemoglobin.

[0036] FIG. 11 shows an example of a monolithic LED IC die that includes a number of distinct optical emission regions that can be electrically interconnected to a number of electrically conductive bond pads, such as via a multiplexer to selectively route signals to desired emission regions to tune or select a spectral output from optics receiving light from the monolithic LED IC die. DETAILED DESCRIPTION

[0037] FIG. 1A illustrates an example of a comparative LED die 10 having a single optical output. These may come with many different electrically conductive electrical current electrical distribution structures, networks, or patterns 1002 such as for injecting current into a p-n junction to thereby produce light as an LED. In the example of FIG. 1A, one electrical connection 1005 is provided on the “top” light emitting region and the other electrical connection 1010 is made with the body 1009 of the die at the bottom. A “flip-chip” type of LED can have both electrical connections made on the light emitting side. There are many variations on the underlying material science or manufacturing processes of making LEDs for different wavelength regions.

[0038] FIG. IB shows an example of some of the illustrative spectra of LEDs in different wavelength regions. In the present approach, no matter what the underlying material science, all LEDs can be made on a particular semiconductor wafer and diced into individual pieces forming individual die. The present approach can use these individual pieces, which can be arranged spatially in a particular system. The LED output light spectra are broadband and, in many cases, spectra from a single type of LED have all the spectral components desired for accurate spectral measurement of gas concentration or other characteristic of a target analyte. In some cases, using only a few types of LEDs can enable coverage over an even broader spectral range. The approach presented herein allows an individual particular (or single) physical LED die to provide independent light outputs, such as which can individually or in combination be spectrally filtered such as for performing a desired spectroscopy.

[0039] Many spectral measurements, such as including gas concentration, blood oxygenation, colorimetry, moisture, and more, can involve active illumination by different wavelengths of light selected appropriately for the target measurement. To improve accuracy of LED-based measurement and to make the device smaller and more cost-effective, it can be desirable to stabilize the spectra of light output from the LED such as to make the illuminated light from the LED have a more controlled wavelength then the broad spectra of light output emitted by the LED. This can involve a spectral slicing of the LED light output spectra, such as to provide multiple different spectral slices of the LED light output, which, in turn can be used for accurate spectroscopic or other measurement. FIG. 1C is block diagram of portions of an active optical illumination system such as for spectroscopic measurement or multi -wavelength measurement of a target object or region. The system is shown in FIG. 1C to provide an example of context for leveraging the significant improvements that can be provided by the multi-emission LED die described herein.

[0040] In FIG. 1C, the system 1100 can employ light that can be output from at least two different LED emission regions that can be located and co-integrated on the same monolithic integrated circuit die. The optics 1108 can be arranged to receive such light output from various LED emission regions (at least two of which are on the same integrated circuit) on the same or different integrated circuits. The optics 1108 can be configured to individually filter the spectra of the received light from individual ones of the LED emission regions, such that the optics 1108 can output or otherwise provide corresponding specific wavelength bins respectively associated with the individual ones of the LED emission regions. Having generated the corresponding specific wavelength bins, the optics 1108 can then combine two or more of such corresponding specific wavelength bins, can illuminate the target with the filtered spectra, or can do both of these. Individual LED emission regions (on the same or different integrated circuit die) can be sequentially energized. A coding strategy can be employed, such as described in U.S. Patent No. 11,704,886. This can help to improve signal-to-noise ratio (SNR) and overall performance. An example of such spectral filtering optics 1108 can include and employ dispersive optics. Such dispersive optics can include one or more gratings (or prisms). The dispersive optics can provide filtering of light output from the individual LED emission regions, such as by appropriately spatially locating respective LED emission regions relative to each other, such as shown in the example of FIG. 2.

[0041] As such, the system 1100 can include individual LED emission regions (at least two of which can be co-integrated on the same integrated circuit die; one or more such integrated circuit die can be included in the system 1100) with each LED emission region providing corresponding respective filtered spectra via the optics 1108. The spectrally filtered wavelength bins may lie next to each other (in wavelength). LEDs can produce spectra that are sufficiently broad to cover the desired adjacent wavelength bins. The present approach can employ one or more multi-emission LED die, such as with multiple spatially distinct and individually addressable light emission outputs. This can help allow for a smaller spectral slicer (e.g., in the optics 1108), which can help improve performance while reducing cost.

[0042] A processor 1103 circuit can be included, such as to provide one or more control signals, signal-processing, or both, such as for overall coordination between respective spectrally filtered light outputs that are used to illuminate the target and transducing and signal-processing of received light from the target. The modulation code or pulse generator 1104 can generate a temporal sequence of pulses or frequency domain codes, such as which can be assigned to respective individual LED emission regions 1106 that can be energized via respective amplifiers 1109. Coded light from these respective LED emission region light outputs can be spectrally filtered and projected by optics 1108.

[0043] The illumination light to the target and the target response light from the target may be received and transduced into an electrical signal by one or more photodetectors. If such light is received before illuminating the target object, then it can be used to form a reference measurement indicative of the light being provided to illuminate the target. Using one or more such reference measurements, one or more measured variations in illumination light can be accounted for in signal-processing performed by the processor 1103. Multiple photodetectors, such as with corresponding amplifiers to amplify the respective electrical signals transduced in response to the incident optical signal, can be employed to form corresponding individual receivers 1111. The various electrical signals can be digitized by the ADC 1112 and signal-processed, such as by the digital signal processor 1114 or the processor 1103, to be decoded or otherwise reassigned, such as to be determined to be emanating from a corresponding spectral channel.

[0044] FIG. 2 shows an example of such a system, which can include a dispersive optical system, such as can include portions of what is shown and described in the above-incorporated Deliwala U.S. Patent No. 11,704,886 (see id., including at FIG. 18D). FIG. 2 shows an example of a dispersive optical system in which the present approach can be used. In FIG. 2, each of the LED die providing a spectral channel is physically separate such as to create different slices of the spectra from each of the LED die, which spectral slices can then be combined to provide combined illumination beam for spectroscopy. Since individual LEDs typically have broad spectra, in cases in which the spectroscopic system can benefit from narrow spectra or from spectral spacings in frequency between the spectral bins that are less than the frequency width of the individual LED’s spectrum, then some of the adjacent individual ones of the die shown in FIG. 2 can be the same type of LED, but with the various ones of the individual LEDs physically placed at different spatial locations in the system to slice respective LED output spectra differently.

[0045] In such an optically dispersive system, the spectral slicing depends on the linear dispersion of the optical system as well as the relative position of the LEDs. For example, most LED die are a few hundred microns long or wide, with 200 pm or 250 pm long or wide LED die as an illustrative example. Due to limitations of die pick-and place machines that place individual ones of the LED die on a circuit board or other substrate, one needs a minimum gap between adjacent LED die for assembly. Thus, one is limited to placing adjacent LED die at a typical center-to-center distance of 300-400 pm. This, in turn, means that the optical system must be designed to provide linear dispersion across such center-to-center distances, such that different slices of the LED spectrum can be accessed to serve the purpose of a particular spectroscopic measurement. Furthermore, die placement errors can lead to errors in the wavelength of the spectral slice from a particular LED. Thus, as explained herein, using one or more monolithic LED die with multiple emission regions (e.g., that are closely spaced according to semiconductor integrated circuit manufacturing lithography limitations instead of less closely spaced distinct LED die that are separated from each other according to the limitations of IC pick-and-place machines), the demands on the optically dispersive system can be reduced.

[0046] FIGS. 3 A, 3B, 3C, and 3D, taken together, show aspects of an example of a comparative approach of using multiple LEDs of the same type, having corresponding individual die, such as shown in FIG. 3C. Each individual LED die is modulated with different codes labelled fi, f2, and t that are arranged to produce a common modulated output after spectral slicing, for an example of oxygen sensor. As explained below with respect to the present approach as illustrated in FIGS. 4A-4D, for comparison with the comparative approach in FIGS. 3A-3D, the present approach can include one or more monolithic LED IC die, at least one of which can include multiple optical emission spectral output regions. The present approach can include a linear arrangement of spectral output regions, as well as a multiple row (e.g., dual -row) arrangement of spectral output regions that can be integrated together on a particular monolithic die with independent electrical control for each corresponding optical spectral output region.

[0047] For example, as shown and described with respect to FIG. 3D, and as explained in detail in the above-incorporated patent documents, a robust oxygen concentration sensor can involve performing spectroscopy, across the spectrum of oxygen, such as with three or more spectral band measurements that are each less than 8 nm wide. By measuring nearby non-absorbing spectral bands, the present system can cancel or attenuate non-desirable effects such as from dirty optics or changes in the optical system transmission, since such effects are likely to affect similarly in the absorption bands of interest and the non-absorbing bands at nearby wavelengths. Using a reference detector 3020 to make a reference measurement, any changes due to variations in the illumination source, the optical encoding system, and / or that of the electronics that drive the LEDs can be cancelled or attenuated.

[0048] FIG. 3D shows that the typical LED spectrum is quite wide relative to that of oxygen. In FIG. 3D, the three spectral bands shown as the dashed-box regions can be modulated at three different modulation frequencies fltf2and f3or using different time-domain codes. Each identical LED die can be used to provide correspondingly modulated slices of the spectrum of interest such as for making absorption measurements at the frequencies of those slices. If we use a 250 pm LED die and we placed an adjacent die with a gap of 30 pm therebetween, the optical dispersion must be at least 8 nm for every 280 pm at the O2 absorption wavelength of 767 nm. Thus, we need dispersive power of 2 0 / g ~ 35 pm / nm. For a simple dispersive system used at a Littrow angle as shown in FIG. 3A, dispersive power of a system in which the focal length of the lens is FL and is given by:

[0049] The above equation shows that with 600 lines / mm grating, we will need focal length of - 50 mm. The entire optical system of FIG. 3A uses three LEDs placed linearly as shown in the LED and the output plane as shown in FIG. 3B to produce the above-mentioned slices of the spectra of the outputs of otherwise identical LEDs. The three identical LEDs 3005 with gaps between them are shown in FIG. 3C. While FIG. 3C is illustrated for three spectral bins for oxygen, it similarly applies to many cases of materials measurement with two or more spectral bins. Note that the focal length of the system and the dispersive power of the grating determine the distance between the LEDs. For a more compact system, we need higher dispersive power and smaller focal length FL. At some point, limitations of dispersive power of the gratings prevent further size reduction. In the example of FIG. 3A-3D, we used a 600 lines / mm grating and FL = 50 mm. We can use 1500 lines / mm grating paired with 15 mm focal length system to make it more compact. But any further reduction is extremely difficult as higher dispersion is very difficult to achieve while still maintaining a high level of manufacturing robustness.

[0050] The only available path is to reduce the LED die size and LED spacings between adjacent LED die. Smaller LED dies are harder to make, and it is harder to use them in high volume pick-and-place machines and is harder to maintain requisite smaller gaps between the individual LED die. Therefore, the present approach can create an individual (e.g., single) monolithic LED die that has multiple optical emission regions that are electrically isolated from each other and in which such multiple emission regions are independently addressable, as explained herein.

[0051] FIGS. 4A, 4B, 4C, and 4D taken together show aspects of an example of the present approach using multiple LEDs of the same type on a shared monolithic die, such as with corresponding individual spectral output regions that can be defined using semiconductor processing. Thus, these various corresponding more closely-spaced spectral output regions can be arranged together (with at least two such spectral output regions located on the same monolithic LED IC die) to produce a common modulated output, such as for an improved example of an oxygen sensor. Since the spectral output regions are closer together, in this approach, the system can be smaller, more convenient to build, and performance is improved. The gap between multiple optical emission regions on the same monolithic LED IC die is now lithographically defined and can be maintained with high level of accuracy compared to the pick-and-place approach for corresponding multiple individual LED dice employed for FIGS. 3A-3D.

[0052] In the present approach, instead of using three individual physical LED die, the present approach can employ a single physical LED die 4005A, such as shown in FIG. 4C with multiple (e.g., two or more) closely spaced optical emission regions (e.g., three optical emission regions as shown at left in FIG. 4C, or five optical emission regions as shown at right in FIG. 4C with respect to alternative LED die 4005B), respectively individually controlled by corresponding electrical connections, such that they can respectively be individually modulated for encoding by applying desired electrical modulation input signals. FIG. 4C also shows an example of alternative LED die 4005B in which the (e.g., five) optical emission regions 4012 can, if desired, even be at a pitch closer than their corresponding electrical bond pads 4014 forming corresponding respective electrical connections to these individual optical emission regions 4012. Using the present approach these optical spectral emission regions 4012 can be closer to one another than in a comparative example, in which the limitations on spacing between physically adjacent spectral emissions regions are imposed by dicing and assembly pick-and-place capabilities. And, as explained here, the present approach can help solve some of the most important practical problems of spectroscopic measurements, particularly when combined with coding the illumination light. If these spectral emission regions are physically located only 110 pm apart, and, because multiple ones of the spectral emission regions are located on the same monolithic LED die, the different spectral emission regions output corresponding light having spectral characteristics are substantially alike with respect to each other. This is because the same-die LED manufacturing produces very similar emission characteristics such as central wavelength for adjacent regions and the monolithic LED IC die shares the same temperature during use. Since the LED emission regions are now closer, using the same grating or dispersive power as described with respect to FIGS. 3A-3D, we can now use a 20 millimeter lens to achieve the same spectral spacing and resolution around the desired oxygen absorption spectral features. The lens diameter also shrinks for the same numerical aperture and so does the size of the grating element and the rest of the housing carrying the optics componentry. In fact, direct comparison shows almost 2.5X reduction in linear length of the system. Thus, FIG. 4A shows a much smaller coded light spectrometer, compared to FIG. 3A, but with identical performance. The device of FIG. 4A with a single LED die as shown in FIG. 4B and with multiple emission region makes the overall system smaller, easier to manufacture, less expensive, and more robust. Furthermore, during operation, temperature of the entire LED die is identical or very nearly so, making the temperature dependent spectral shift similar on all emission regions since these emissions regions can all be located on the same LED die. Also as further explained elsewhere herein, a linear arrangement of spectral output regions, as well as a dual-row arrangement of spectral output regions can be integrated together on a particular monolithic die with independent electrical control for each corresponding optical region.

[0053] To make the comparison more concrete, the smallest focal length is around 20 mm, with discrete LEDs such as shown in the example of FIGS. 3A- 3D, even when accompanied by a high dispersion grating of 1500 lines / mm. By contrast, by using multi -emission die, such as shown in the example of FIGS. 4A-4D, one can use focal length of 6.7 mm and perhaps even smaller. Thus, a same-die multi-emission LED die enables more compact and higher performance spectral measurement systems. This can be particularly important for handheld or wearable devices or sensors that need to be positioned in tight spaces. Examples can include an SpCh sensor in a wrist-worn smartwatch or a glucose sensor attached to an armband or a handheld moisture sensor. FIGS. 10A and 10B show an example of portions of a compact SpCh sensor that can use orange / green spectral bands of hemoglobin. Enabling using such closely- spaced spectral bands for spectroscopy using the present approach can also help inhibit or prevent readings from being affected by changes in skin color and can help reduce motion artifacts. Similarly, one can configure and provide a compact temperature sensor in which spectral changes in the temperature transducer are due to temperature, such as providing one or more fiber Bragg grating based sensors.

[0054] Spacing between adjacent optical spectral emission regions can be quite small using the present approach of providing multiple such LED emission regions on the same monolithic IC die. Such spacing between adjacent optical spectral emission regions can be as small as 50 microns, limited only by allowed electrical and optical cross-talk between emission regions and the required signal for the measurement. In many applications, one can significantly reduce the focal length of the lens, as discussed earlier, and thus make a very compact spectroscopic componentry module. A spectroscopic componentry module as small as a few millimeters in size becomes possible using the present approach.

[0055] FIGS. 5A, 5B, 5C, and 5D together show portions of another example, such as in which multi-gas detection with seven emission regions can be combined with controller circuitry and optics as described or incorporated herein and configured to detect alcohol, water vapor, and CO2. Such a multi-gas sensor can be approached using one or more monolithic die, at least one of which (or each of which) can include multiple different spectral emission output regions. Thus, the example of these FIGS. 5A, 5B, 5C, and 5D provide another illustrative example of more complex spectroscopic measurement task in another spectral region.

[0056] Measurement of alcohol in breath of a human subject is important for safety and prevention of accidents related to alcohol-impairment of driving. Alcohol vapor in breath can be measured by infrared absorption spectroscopy. This can include measuring light absorption at wavelengths around 3400 nm, such as shown in FIG. 5D. Exhaled human breath also has high concentration of water vapor and carbon dioxide. Thus, it would be advantageous to measure all three breath constituents (e.g., alcohol, water vapor, and carbon dioxide spectra) rapidly, and to lock to the periodic changes in the absorption over multiple breathing cycles. Such techniques can help allow removal of background absorption characteristics from the desired measurement. While spectra of these gases are all available, the task of making a low-cost device that operates in a difficult environmental condition, such as that of a car or heavy machinery that may be regularly exposed to extremes of temperature, is very difficult. This is because both LEDs and photodetectors in this spectral region are less efficient and highly temperature sensitive. LEDs shift their spectrum and exhibit a decrease in output power with increasing temperature. Photodetectors show changes in responsivity as well as an increase in noise with increasing temperature — sometimes to the extent as to require cooling, for particular applications, which the present approach can help avoid. One approach to overcome these limitations is to use two photodiodes with different optical filters to perform two-color measurement - one filter is configured to be sensitive to the wavelengths that are absorbed and the other is configured to be sensitive to wavelength that are not absorbed. But this approach cannot differentiate between changes in the source spectrum (noting that an LED source spectrum is quite sensitive to temperature) or changes in the response of the two photodiodes, which are also temperature and bias sensitive. Many of these problems can be reduced by increasing the measurement path length. But increasing the measurement path length makes this approach bulky and expensive. Furthermore, such an approach gets increasingly expensive and requires complex calibrations for multi-gas sensing with many different photodiodes and filters. These limitations can be addressed by using differential path length, such as described in US Patent No. 12,228,502 and US Patent No. 10,866,185.

[0057] FIG. 5A shows an example of portions of a system for measurement of all three gases - alcohol, water vapor, and carbon dioxide using a single monolithic broadband LED die with seven emission band regions, such as shown in FIG. 5C. The seven emission band regions, together with an example of a MWIR LED spectrum, is shown in FIG. 5D. As shown in FIG. 5A, two photodetectors - a first reference photodetector 3010 to detect light that has not passed through or interacted with an absorption volume, and a second measurement photodetector 3030 to detect light that has passed through and interacted with the absorption volume, can be employed to measure all three of the alcohol, water vapor, and carbon dioxide gases. Since GaSb semiconductor material is fragile, dicing smaller LED die from a GaSb semiconductor wafer is difficult or leads to large scrap. But, as shown in FIG. 5C, the present approach can employ a single larger LED IC die of about 1.3 mm in size, which can be included in or used with the system of FIG. 5A to provide multi-gas measurement functionality. Also, as further explained below, a linear arrangement of spectral output regions, as well as a dual-row arrangement of spectral output regions can be integrated together on a particular monolithic LED IC die with independent electrical control for each corresponding optical spectral output region. FIGS. 6 A, 6B, 6C, and 6D take together show an example of an approach of how to configure a multi-emission LED die so as to help reduce or eliminate the drift that may exist between the two measurements corresponding to (1) a same-die reference path that does not interact with the target substance and (2) a measurement path that does interact with the target substance under test. Such drift between measurements can occur due to temperature dependent responsivity changes or changes in the amplifier gain of the electronic amplifier attached to the corresponding photodiodes. In many cases, these photodiodes and amplifiers are in proximity to each other and thus are likely to experience very similar local temperatures or environmental conditions. In many systems exposed to real -world environments, such as in which one side (e.g., region near a lateral edge) is hotter / colder because it is situated next to a hot / cold piece of equipment, these temperature drifts can seriously reduce sensor performance. For example, most of the cooling system compressors in the world would benefit from being able to measure leakage of refrigerants. But, in such a use case, the spectroscopic refrigerant measurement sensor can be exposed to large thermal gradients.

[0058] For these or other temperature-sensitive or other suitable use cases, the example of FIGS. 4A-4D or FIGS. 5A-5D - which can be generalized to any similar measurement system - can be used with additional optional variation that replaces the 3 or 5 -emission region LED die with 6 or 10-emission region LED die 6006 such as of two rows, such as shown in FIG. 6B. FIG. 6A shows an example of a configuration in which the optical emission rays from the multiple spectral emission region single LED die 6006 going towards a dispersive and spectral combining system, such as shown previously, and two like-coded light beams 6010 corresponding to optical emissions from the upper and lower portions of the LED die 6006. The optical ray trace on the commonly-shared input and output plane 6011 is shown in the example of FIG. 6C. The left portion of FIG. 6C shows an example of the emission from the six emitting regions arranged in two rows. After the light has passed through a dispersive system, similar to that shown in FIG. 4A or 5A, the two spectrally sliced and coded outputs are shown on the right of FIG. 6C. Since the horizontal position of the emission region determines the spectral slicing by the dispersive system, a vertical pair of emission regions can provide the same spectral slice from the individual emission regions in the vertical pair of emission regions. As shown in FIG. 6B and FIG. 6C, we can encode all six emission regions with six different frequencies or temporal codes. The pairs f f4, f2fs, or f3f6can be spectrally identical due to the arrangement of the optical system with the LEDs monolithically located on the same-die. At the exit of the system, the upper beam (for example) can be separated from the lower beam. One of the beams - e.g., the top one as shown in FIG. 6C, can be directly sent to the photodetector 3030, while the lower beam shown in FIG. 6C can be used to measure the gas or the material of interest and then sent to the same photodiode 3030, with all six individually modulated spectral channels measured by the same receiver. Now, the upper and the lower beams can be separated by the decoding process and can respectively be used as a reference measurement and as the main measurement. As described earlier, division of a particular wavelength channel’s measurement return signal by a corresponding reference channel’s return signal can normalize the measurement signal, such as to help reduce or eliminate changes in variations of the illumination source and illumination channel as well as helping to reduce or eliminate changes the receiver channel.

[0059] To recapitulate, the present approach can employ a combination of (1) coding for spectral measurement, (2) same-die spectral slicing from the same LED die, and (3) a commonly-shared receiver for both reference channel measurements and main measurements, which can thereby help eliminate all sources of error and difficulty. These can include:

[0060] 1. Elimination of dark currents and low-frequency 1 / f noise, due to coding;

[0061] 2. Ambient light and electronic harmonics rejection, due to coding;

[0062] 3. Changes in the source spectrum from division by a reference signal after coding;

[0063] 4. Higher mechanical stability and smaller optical system due to closer spacing of emission regions by locating such emission regions on the same monolithic die;

[0064] 5. Changes in the receiver electronics or photodetector across time, temperature, or from part-to-part, due to use of commonly-shared receiver for detecting each of the slices of the measurement signal as well as for detecting the reference signal; 6. Higher SNR as a result of the above leads to smaller path length requirements for absorption, which can help further lower the cost and increase the performance of the present system.

[0065] Examples of multiple emission regions from a single LED die are shown in FIGS. 4C, 5C, and 6B. In general, one multi-emission LED die or more than one multi-emission LED die can be used to perform spectroscopic analysis, and the present techniques can allow use in combination with a spectroscopy device, and can provide a first number of spectral channels and a second number of multi-emission LED die, wherein the second number of multi-emission LED die can be fewer in than the first number of spectral channels. For a given multiemission LED die, the emission regions on that multi-emission LED die output light having like spectral properties, because such emission regions are located on the same multi -emission LED die. Between different multi -emission LED die, however, the spectral properties can be different from each other, if desired, which can be exploited for generating spectra at various wavelengths or wavelength bands of interest for spectral filtering, spectroscopic analysis, or both.

[0066] FIGS. 7A and 7B together show examples of a monolithic LED die with multiple individually controlled spectral output emissions region. FIG. 7A shows an example of a staggered row of spectral output emission regions LED die 7005, which can help to help increase spectral resolution. FIG. 7B shows an example of a flip-chip LED die 7006 in which emission occurs through the substrate with patterned metallization 7012 on the back to allow light to escape. Individual metallizations 7014, such as respectively individually surrounding each of the corresponding optical spectral emission regions, can be electrically isolated from each other, such as by respective gaps 7020A between adjacent metallizations 7014. These gaps 7020A may include corresponding trenches, such as to provide good optical isolation and an essentially vertical path of electrical charge carriers through the LED substrate. Similar isolation can be provided in an epitaxial layer 7016 such as shown as isolation gap or isolation trench 7020B. Each of the optical spectral emission regions can include a corresponding electrical contact that can be individually wire-bonded to a printed circuit board (PCB) or another substrate, such as indicated by respective connections 7014. This can allow individual emission regions to produce light and to be emitted in an upward direction as shown in FIG. 7B from the top-face of the flip-chip LED die.

[0067] FIG. 7C extends the example of FIG. 7B, in which a die such as the multi-emission region LED die 7006 can be attached another substrate 7030, such as can be made from glass or silicon, through which electrically conductive connections such as connections 7014 can be made. The substrate 7030 can also be configured to provide optical componentry providing an optical function, such as which can include one or more refractive or diffractive lenses or one or more dispersive gratings.

[0068] FIG. 8 shows an example of a broadband spectrometer of the type shown in FIG. 2, but in which multiple, multiple-optical-emissions-output LED die can be used to provide a SWIR measurement. Since there are no LEDs available that produce such a broadband light covering emissions from 1200 nm to 2000 nm, available multiple (separate) LED die can be used. In the 20-channel example shown in FIG. 8, we show an example in in which we need use only 7 multi- optical-emission region LED dies instead of 20 single-optical-emission region LED dies, with each of the multi-optical-emission region LED dies having multiple emission regions, such as shown and described herein. For example, a 1200 nm multi-optical-emission region LED die can be include three independently controlled emission regions while a 1900 nm multi -opti cal - emission region LED die can include four independently controlled emission regions, because 1900 nm LEDs tend to have broader spectra. Thus, it is possible to use the present approach to manufacture multi-optical-emission region LED dies with broad emission by using epitaxial growth and controlling the band structure, which, in turn, controls the spectral profile of emission. Thus, a multi- optical-emission region LED die with broad emission from 1500 to 1900 nm, with multiple emission regions on at least one monolithic die, such as described herein, can be used to directly measure glucose concentration or measure spectra of tissues to measure its protein and fat content.

[0069] FIGS. 9A, 9B, 9C, 9D, and 9E together show various patterns of multiple LED output light emission regions 902 from a single LED die 900. For example, FIGS. 9A, 9B, show various examples of one-dimensional patterns with a single row of individually addressable spectral emission regions 902, while FIGS. 9C and 9D show an example of a dual row of emission regions 902. FIG. 9A shows a top view of a single LED die 900 including multiple distinct, independently-controllable LEDs providing corresponding independently-controllable spectral light output emission regions 902. In FIG. 9 A, each LED emission region 902 can include a first top-side electrically conductive bonding pad 904. Using a corresponding pad 904, an electrical connection can be wire-bonded, ball-bonded, or otherwise affixed. Thus, each pad 904 can provide an independently-controllable electrical contact to which an independently controllable electrical signal can be applied. Each LED emission region 902 can also include a corresponding bottom-side electrically conductive bonding pad, such as to which a separate and distinct return electrical signal path can be individually-provided. The individual distinct LED emission regions 902 on the shared single LED die 900 can be separated from each other by corresponding electrically-insulating isolation regions 906, such as to inhibit electrical conduction between individual ones of the LED emission regions 902 on the shared LED die 900. Such insulating isolation regions 906 will inhibit a particular LED emission region 902 from producing light output in response to an electrical signal being applied to an adjacent LED emission region 902, such that each LED emission region 902 can be independently controlled to produce its own light output.

[0070] In FIG. 9A, the multi-LED die 900 includes multiple individually addressable LED emission regions 902 on a shared monolithic multi-LED die 900. Therefore, the distance between LED emission regions 902 on the shared monolithic LED die 900 can be less than the dicing distance that would otherwise be required to dice into respective individual LED die, each individual LED die having only a single corresponding LED. Thus, higher spatial resolution spectral emission can be obtained using the present approach that includes multiple individually addressable LED emission regions 902 on a shared monolithic multi-LED die 900. This, in turn, reduces the constraints on the optics coupled to receive illumination from the LED emission regions 902. Such eased constraints on optics are particularly useful for use in generating separately modulated spectral slices for performing coded spectroscopy, such as described or incorporated herein.

[0071] FIG. 9B shows a top view of a single LED die 900 including multiple distinct, independently-controllable LED emission regions 902, similar to what is shown in FIG. 9A, but also showing corresponding electrically-conductive signal spreading structures 908 (“current distribution networks”) to spread the respective electrical signals obtained via the independently addressable bond pads 904 across a greater portion of an individual LED emission region’s 902 semiconductor body. Thus, using such current distribution networks or signal spreading structures 908 can help provide more efficient and more intense illumination in response to a given amount of electrical power received by a particular LED emission region 902.

[0072] FIG. 9C shows a top view, similar to what is shown in FIGS. 9A-9B, of a single LED die 900 including multiple distinct, independently-controllable LED emission regions 902 — which need not be at the same or a greater pitch than the semiconductor process design rules specification for a minimum spacing between individual adjacent electrically conductive pads 904, having a minimum process-specified pad dimension, and with the pads 904 arranged a row. Instead, the individual LED’s corresponding spectral emissions regions 902 can be formed at a pitch that is even less than the pitch between adjacent pads 904 in the row of pads 904. The electrical isolation regions 906 can be curved or otherwise shaped to maintain electrical isolation between adjacent LEDs and their corresponding spectral output emissions regions 902, despite the pitch difference between pads 904 and LED spectral emissions regions 902, such as shown in FIG. 9B. Respective electrical conductors 910 can extend between respective pads 904 and respective LED spectral emissions regions 902. Such respective electrical conductors 910 may form or be connected to corresponding electrically-conductive signal spreading structures 908 (“current distribution networks”), such as to spread the respective electrical signals obtained via the independently addressable bond pads 904 across a greater portion of an individual LED’s semiconductor body within which its LED spectral emission region 902 is formed. The LEDs or their corresponding spectral output emission regions 902 can be arranged, shaped, or both, such as to improve spectral resolution and / or to provide lower cross-talk between adjacent LEDs or between their corresponding emissions regions 902.

[0073] FIG. 9C shows a top view, similar to what is shown in FIG. 9A, but with the individual LEDs and corresponding spectral output emission regions 902 being arranged on the same die 900 in multiple rows, rather than in a single row. The individual LEDs and corresponding spectral output emission regions 902 can be arranged in a staggered manner with respect to each other, such as by offsetting a particular row of LEDs from an adjacent row of LEDs, such as shown in FIG. 9D. Such a multiple row staggered arrangement can be employed such as to improve spectral resolution and / or to provide lower cross-talk between adjacent LEDs or between their corresponding emissions regions 902. We can also similarly arrange emission regions with smaller pitch, such as shown in FIG. 9B, than a corresponding pitch of corresponding bond pads, such as to be arranged in two or more rows.

[0074] FIG. 11 shows an example of a monolithic LED IC die 1150 that includes a number (e.g., 24 shown in FIG. 11, spaced 10 microns apart from each other) of distinct optical emission regions 1152 that can be electrically interconnected to a number of electrically conductive (e.g., 65 micron square) bond pads 1154, with an accompanying x-axis and a y-axis illustrating dimensions in microns. Each individual emission region 1152 can be arranged to output light to a corresponding spectral filter (e.g., of optics 1108) that receives light output from the corresponding emission region, and spectrally filters such light output to a corresponding spectral band that is narrower than the broader band provided by each of the distinct optical emission regions 1152, such as shown and described herein, e.g., with respect to optics 1108. The individual spectral filters provided by the optics 1108, corresponding to the respective optical emission regions 1152, can be different from each other such that one or more or all of the different spectral filters can optionally output different spectral bands from one or more or all others of the spectral filters.

[0075] An electrical signal multiplexer circuit can be provided on the same monolithic LED integrated circuit die 1150. The multiplexer circuit can allow routing of various electrical signals from various individual ones of the bond pads 1154 to various individual ones of the emission regions 1152. This can allow one or more individual ones of the emission regions 1152 to be selectively activated, such as to output (via the optics 1108 that provide corresponding spectral filters) a desired spectral band of light. Thus, the multiplexer circuit can be used to “tune” the wavelengths of light being emitted from the monolithic LED IC die 1150 via selected one(s) of the emission regions 1152. In this way, a tunable light source can be provided, such as for use, together with encoding, in the system shown in FIG. 1C, or for any other application (with or without encoding) that may benefit from using a tunable laser or tunable narrowband light source.

[0076] The electrical signals multiplexed by the multiplexer circuit to individual ones of the emission regions 1152 need not be digital on / off signals, but can include different currents or voltages. For example, different currents can be provided to three adjacent ones of the emission regions 1152, such as to obtain a Gaussian or other desired profile using concurrent light emission from these adjacent ones of the emissions regions 1152, together with their corresponding individual optical filtering, such as can be provided using the optics 1108, such as described herein. Electrical isolation between adjacent ones of the emission regions 1152 can be provided, such as by manufacturing dielectric-filled trenches between adjacent ones of the emission regions 1152. Using such an approach, an expensive tunable laser (e.g., such as used in laser-based thickness measurement system) can be replaced by a multiple emission region monolithic LED integrated circuit. Some examples of other applications can include measurement of food packaging plastics, such as ethylene vinyl alcohol copolymer (EVOH), or other materials. Thus, the tunable light source shown in FIG. 11 can be used with or without the coding techniques described herein, for various purposes.

[0077] The underlying material science of the LED continues to make advances and complex quantum well structures can provide spectrally broadband optical output. Many approaches can be considered for electrically isolating epitaxially grown structures including ion-beam bombardment, quantum well mixing, or etching of the epitaxial layers. In this document, we are focused not on the underlying light emission diode (LED) technology but in providing multiple light spectral emission locations that can be individually controlled, such for use in improved spectrometry.

[0078] Although the above description has focused on examples showing spectroscopy applications directed toward a single species such as oxygen, the spectroscopic analysis applications can also include multiple gases such as carbon dioxide, alcohol, water vapor or tissue spectroscopy to measure multiple spectral features using one or multiple, multi-emission LED die. Similarly, the present techniques can be applied to other spectroscopic measurement or analysis, such as can include measurement of concentration of gases including at least one of oxygen, methane, alcohol, carbon monoxide, carbon dioxide, ammonia, oxides of nitrogen or anesthesia gases, for some other examples as well as limitless numbers of materials subject to spectral analysis. Some illustrative examples are listed below: a. Multiple emissions near green-orange region for high resolution measurement of oxygenation of blood such as shown in FIG. 10A; b. Moisture and water measurement around the water absorption in the 1460 nm region such as shown in FIG. 10B; b. Protein / fat / sugar analysis of plants in the SWIR region; c. Quality of gasoline or other fuel; d. Leak measurement of gases used in HVAC and other compressors (e.g., similar to measurement of methane, ethane, etc.), similar to the description herein corresponding to FIGS. 5A-5D; e. In-situ temperature measurement of liquids or tissue or chemical reactants by spectral analysis of water absorption peaks; f. Measurement of changes in the bandgap of semiconductor during processing or testing for in-situ temperature / strain measurement; g. Measurement of temperature or strain using fiber Bragg gratings or similar optical systems (such as described in Fig. 13 in U.S. Patent No. 11,704,886); h. Measurement of film thickness, e.g., of thin films; i. Measurement of performance of photonic integrated devices; j . Among others. The above description is intended to be illustrative, and not restrictive. An illustrative, non-limiting list of examples (or aspects) is provided below.

[0079] Aspect 1 can include or use a monolithic multi-emission LED die with multiple independent emission regions on the monolithic multi-emission LED die. The monolithic multi-emission LED die can include a first emission region. The first emission region can be electrically coupled to a first electrical input contact, such as for receiving a first electrical input signal for controlling first light output from the first emission region. A second emission region can be electrically coupled to a second electrical input contact, such as for receiving a second electrical input signal for allowing independent controlling of the second light output from the second emission region independent of controlling the first light output from the first emission region via the first electrical input signal.

[0080] Aspect 2 can include or use, or can optionally be combined with Aspect 1 to include or use, the first emission region being electrically isolated from the second emission region on the multi-emission LED die.

[0081] Aspect 3 can include or use, or can optionally be combined with any of Aspects 1 or 2 to include or use, a first spectral filter in a first optical pathway from the first emission region, such as to receive the first light output to which a first optical filtering function is applied by the first spectral filter. A second spectral filter can be located in a second optical pathway from the second emission region, such as to receive the second light output to which a second optical filtering function is applied by the second spectral filter. The first optical filtering function and the second optical filtering function can be capable of being independently specifiable from each other.

[0082] Aspect 4 can include or use, or can optionally be combined with any of Aspects 1 through 3 to include or use, the first spectral filter and the second spectral filter being adjacent to each other and being spaced apart from each other by a distance that is less than a minimum pick-and-place distance (e.g., 10 micrometers) of an IC die pick-and-place machine.

[0083] Aspect 5 can include or use, or can optionally be combined with any of Aspects 1 through 4 to include or use, electronic controller circuitry. The electronic controller circuitry can include a first electrical output, such as for outputting the first electrical input signal to the first electrical input contact of the first emission region. The electronic controller circuitry can include a second electrical output, such as for outputting the second electrical input signal to the second electrical input contact of the second emission region. The first and second electrical outputs can be independently and differently electrically modulated, such as to independently and differently encode the first light output from the first emission region and the second light output from the second emission region.

[0084] Aspect 6 can include or use, or can optionally be combined with any of Aspects 1 through 5 to include or use, an electrically conductive first current spreading structure included in or electrically coupled to the first electrical input contact associated with the first emission region. An electrically conductive second current spreading structure can be included in or electrically coupled to the second electrical input contact associated with the second emission region. The first current spreading structure can be electrically isolated from the second current spreading structure.

[0085] Aspect 7 can include or use, or can optionally be combined with any of Aspects 1 through 6 to include or use, a first pitch spacing between the first light output from the first emission region and the second light output from the second emission region is closer than a second pitch spacing between the first electrical input contact and the second electrical input contact.

[0086] Aspect 8 can include or use, or can optionally be combined with any of Aspects 1 through 7 to include or use, the multiple emission regions including more than two emission regions, such as which can be arranged in first and second rows on the multi-emission LED die.

[0087] Aspect 9 can include or use, or can optionally be combined with any of Aspects 1 through 8 to include or use, emission regions in the first row that can be offset, such as in a staggered manner, from emission regions in the second row.

[0088] Aspect 10 can include or use, or can optionally be combined with any of Aspects 1 through 9 to include or use, emission regions in the first row that can produce respective light outputs at corresponding modulation frequencies and emission regions in second row that can produce respective light outputs at corresponding modulation frequencies of emission. Emission regions in one of the first and second rows can provide respective light outputs that can be directed to a photodetector via a target substance under test, and emission regions in an other one of the first and second rows can provide respective light outputs that can be directed to the photodetector without interacting with the target substance under test to provide a same-die reference signal to the photodetector.

[0089] Aspect 11 can include or use, or can optionally be combined with any of Aspects 1 through 10 to include or use, the first emission region producing a first light output at a first modulation frequency that can be directed to a photodetector via a target substance under test, and the second emission region can produce a second light output at the second modulation frequency that can be directed to the photodetector, such as without interacting with the target substance under test, such as to provide a same-die reference signal to the photodetector

[0090] Aspect 12 can include or use, or can optionally be combined with any of Aspects 1 through 11 to include or use, the monolithic LED die in combination with a spectroscopy device providing a first number of spectral channels and a second number of multi-emission LED die, wherein the second number of multiemission LED die can be fewer than the first number of spectral channels.

[0091] Aspect 13 can include or use, or can optionally be combined with any of Aspects 1 through 12 to include or use, the spectroscopy device being configured to perform spectroscopic analysis of a substance using a single multiemission LED die.

[0092] Aspect 14 can include or use, or can optionally be combined with any of Aspects 1 through 13 to include or use, the spectroscopy device being configured to perform spectroscopic analysis of a substance including measurement of concentration of gases including at least one of oxygen, methane, alcohol, carbon monoxide, carbon dioxide, ammonia, oxides of nitrogen or anesthesia gases.

[0093] Aspect 15 can include or use, or can optionally be combined with any of Aspects 1 through 14 to include or use, the first and second emission regions being located on a top face of the LED die that includes a bottom face including the first and second electrical contacts to which corresponding ones of the first and second electrical input signals can be respectively applied for allowing independent controlling of the second light output from the second emission region independent of controlling the first light output from the first emission region via the first electrical input signal.

[0094] Aspect 16 can include or use, or can optionally be combined with any of Aspects 1 through 15 to include or use, the first and second emission regions emit corresponding first and second light outputs having like spectral content with respect to each other.

[0095] Aspect 17 can include or use, or can optionally be combined with any of Aspects 1 through 16 to include or use, a substrate that can be attached to the multi-emission LED die. The substrate can include: a first electrical pathway that is electrically coupled to the first electrical input contact of the LED die; a first optical pathway that is optically coupled to receive the first light output from the first emission region of the LED die; a second electrical pathway that is electrically coupled to the second electrical contact of the LED die; and a second optical pathway that is optically coupled to receive the second light output from the second emission region of the LED die.

[0096] Aspect 18 can include or use, or can optionally be combined with any of Aspects 1 through 17 to include or use, a substrate, wherein the substrate includes integrated optical componentry receiving at least one of (1) the first light output from the first emission region of the LED die; or (2) the second light output from the second emission region of the LED die.

[0097] Aspect 19 can include or use, or can optionally be combined with any of Aspects 1 through 18 to include or use, a substrate, wherein the substrate can include monolithically integrated optical componentry comprising at least one of refractive, diffractive, or dispersive optical componentry.

[0098] Aspect 20 can include or use, or can optionally be combined with any of Aspects 1 through 19 to include or use, the first emission region and the second emission region being configured to provide at least one wavelength targeting a spectroscopic characteristic wavelength of a target, wherein the target is at least one of SpO2, glucose, or HlbalC.

[0099] Aspect 21 can include or use, or can optionally be combined with any of Aspects 1 through 20 to include or use, electronic controller circuitry that can operatively differently encode the first light output from the first emission region from the second light output from the second emission region.

[0100] Aspect 22 can include or use, or can optionally be combined with any of Aspects 1 through 21 to include or use, a multiplexer circuit, such as for selectively controlling the first and second emission regions, such as for tuning a light output from optics receiving light from the first and second emission regions such as to tune or select between different spectral bands for the light output from the optics.

[0101] Aspect 23 can include or use, or can optionally be combined with any of Aspects 1 through 22 to include or use, individual ones of multiple emission regions on the monolithic multi-emission LED die being configured to be sequentially energized such as to provide a tunable light source. Aspect 24 can include or use, or can optionally be combined with any of Aspects 1 through 23 to include or use, a method of using a monolithic multiemission LED die with multiple independent emission regions on the monolithic multi-emission LED die. The method can include: providing a first electrical input signal, via a first electrical input contact to a first emission region of the multiple independent emission regions on the monolithic multi-emission LED die for controlling first light output from the first emission region; and, providing a second electrical input signal, via a second electrical input contact to a second emission region of the multiple independent emission regions on the monolithic multi -emission LED die for controlling second light output from the first emission region.

[0102] Aspect 25 can include or use, or can optionally be combined with any of Aspects 1 through 24 to include or use, filtering the first light output from the first emission region using a first spectral filter in a first optical pathway from the first emission region to define a first spectral band output by the first spectral filter, the first spectral filter applying a first spectral filtering function; filtering the second light output from the second emission region using a second spectral filter in a second optical pathway from the second emission region to define a second spectral band output by the second spectral filter, the second spectral filter applying a second spectral filtering function. The first optical filtering function and the second optical filtering function can be capable of being independently specifiable from each other.

[0103] Aspect 26 can include or use, or can optionally be combined with any of Aspects 1 through 25 to include or use, selectively energizing the first and second emission regions to tune light output between the first spectral band and the second spectral band.

[0104] Aspect 27 can include or use, or can optionally be combined with any of Aspects 1 through 26 to include or use, independently and differently modulating the first and second electrical input signals to independently and differently encode the first light output from the first emission region and the second light output from the second emission region.

[0105] The above-described examples or aspects (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

THE CLAIMED INVENTION IS:

1. A monolithic multi -emission LED die with multiple independent emission regions on the monolithic multi-emission LED die, the multi-emission LED die including: a first emission region, electrically coupled to a first electrical input contact for receiving a first electrical input signal for controlling first light output from the first emission region; and a second emission region, electrically coupled to a second electrical input contact for receiving a second electrical input signal for allowing independent controlling of the second light output from the second emission region independent of controlling the first light output from the first emission region via the first electrical input signal.

2. The multi -emission LED die of claim 1, wherein the first emission region is electrically isolated from the second emission region on the multi-emission LED die.

3. The multi -emission LED die of any of claims 1 or 2, in combination with: a first spectral filter in a first optical pathway from the first emission region to receive the first light output to which a first optical filtering function is applied by the first spectral filter; and a second spectral filter in a second optical pathway from the second emission region to receive the second light output to which a second optical filtering function is applied by the second spectral filter; and wherein the first optical filtering function and the second optical filtering function are capable of being independently specifiable from each other.

4. The multi -emission LED die of claim 3, wherein the first spectral filter and the second spectral filter are adjacent to each other and spaced apart from each other by a distance that is less than a minimum pick-and-place distance of an IC die pick-and-place machine.

5. The multi -emission LED die of any of claims 1 through 4, in combination with electronic controller circuitry comprising: a first electrical output, outputting the first electrical input signal to the first electrical input contact of the first emission region; and a second electrical output, outputting the second electrical input signal to the second electrical input contact of the second emission region; and wherein the first and second electrical outputs are independently and differently electrically modulated to independently and differently encode the first light output from the first emission region and the second light output from the second emission region.

6. The multi -emission LED die of any of claims 1 through 5, comprising: an electrically conductive first current spreading structure included in or electrically coupled to the first electrical input contact associated with the first emission region; and an electrically conductive second current spreading structure included in or electrically coupled to the second electrical input contact associated with the second emission region; and wherein the first current spreading structure is electrically isolated from the second current spreading structure.

7. The multi -emission LED die of any of claims 1 through 6, wherein a first pitch spacing between the first light output from the first emission region and the second light output from the second emission region is closer than a second pitch spacing between the first electrical input contact and the second electrical input contact.

8. The multi -emission LED die of any of claims 1 through 7, wherein the multiple emission regions include more than two emission regions arranged in first and second rows on the multi-emission LED die.

9. The multi -emission LED die of claim 8, wherein emission regions in the first row are offset in a staggered manner from emission regions in the second row.

10. The multi -emission LED die of claim 8, wherein: emission regions in the first row produce respective light outputs at corresponding modulation frequencies and emission regions in second row produce respective light outputs at corresponding modulation frequencies of emission; and emission regions in one of the first and second rows provide respective light outputs that are directed to a photodetector via a target substance under test, and emission regions in an other one of the first and second rows provide respective light outputs that are directed to the photodetector without interacting with the target substance under test to provide a same-die reference signal to the photodetector.

11. The multi -emission LED die of any of claims 1 through 10, wherein: the first emission region produces a first light output at a first modulation frequency that is directed to a photodetector via a target substance under test, and the second emission region produces a second light output at the second modulation frequency that is directed to the photodetector without interacting with the target substance under test to provide a same-die reference signal to the photodetector12. The multi -emission LED die of any of claims 1 through 11, included in or in combination with a spectroscopy device providing a first number of spectral channels and a second number of multi -emission LED die, wherein the second number of multi-emission LED die is fewer than the first number of spectral channels.

13. The multi -emission LED die of claim 12, wherein the spectroscopy device is configured to perform spectroscopic analysis of a substance using a single multi-emission LED die.

14. The multi -emission LED die of claim 12, wherein the spectroscopy device is configured to perform spectroscopic analysis of a substance including measurement of concentration of gases including at least one of oxygen, methane, alcohol, carbon monoxide, carbon dioxide, ammonia, oxides of nitrogen or anesthesia gases.

15. The multi -emission LED die of any of claims 1 through 14, wherein the first and second emission regions are located on a top face of the LED die that includes a bottom face including the first and second electrical contacts to which corresponding ones of the first and second electrical input signals can be respectively applied for allowing independent controlling of the second light output from the second emission region independent of controlling the first light output from the first emission region via the first electrical input signal.

16. The multi -emission LED die of any of claims 1 through 15, wherein the first and second emission regions emit corresponding first and second light outputs having like spectral content with respect to each other.

17. The multi -emission LED die of any of claims 1 through 16, in combination with a substrate that is attached to the multi-emission LED die, wherein the substrate includes: a first electrical pathway that is electrically coupled to the first electrical input contact of the LED die; a first optical pathway that is optically coupled to receive the first light output from the first emission region of the LED die; and a second electrical pathway that is electrically coupled to the second electrical contact of the LED die; and a second optical pathway that is optically coupled to receive the second light output from the second emission region of the LED die.

18. The multi -emission LED die of claim 17, in combination with the substrate, wherein the substrate includes integrated optical componentry receiving at least one of (1) the first light output from the first emission region of the LED die; or (2) the second light output from the second emission region of the LED die.

19. The multi -emission LED die of claim 17, in combination with the substrate, wherein the substrate includes monolithically integrated optical componentry comprising at least one of refractive, diffractive, or dispersive optical componentry.

20. The multi -emission LED die of any of claims 1 through 19, wherein the first emission region and the second emission region are configured to provide at least one wavelength targeting a spectroscopic characteristic wavelength of a target, wherein the target is at least one of SpO2, glucose, or HlbalC.

21. The multi -emission LED die of claim 20, in combination with electronic controller circuitry that operatively differently encodes the first light output from the first emission region from the second light output from the second emission region.

22. The multi -emission LED die of any of claims 1 through 21, including a multiplexer circuit for selectively controlling the first and second emission regions for tuning a light output from optics receiving light from the first and second emission regions to tune or select between different spectral bands for the light output from the optics.

23. The multi -emission LED die of claims 1 through 21, wherein individual ones of multiple emission regions on the monolithic multi -emission LED die are configured to be sequentially energized to provide a tunable light source.

24. A method of using a monolithic multi-emission LED die with multiple independent emission regions on the monolithic multi-emission LED die, the method including:providing a first electrical input signal, via a first electrical input contact to a first emission region of the multiple independent emission regions on the monolithic multi -emission LED die for controlling first light output from the first emission region; and providing a second electrical input signal, via a second electrical input contact to a second emission region of the multiple independent emission regions on the monolithic multi-emission LED die for controlling second light output from the first emission region.

25. The method of claim 24, further comprising: filtering the first light output from the first emission region using a first spectral filter in a first optical pathway from the first emission region to define a first spectral band output by the first spectral filter, the first spectral filter applying a first spectral filtering function; filtering the second light output from the second emission region using a second spectral filter in a second optical pathway from the second emission region to define a second spectral band output by the second spectral filter, the second spectral filter applying a second spectral filtering function; and wherein the first optical filtering function and the second optical filtering function are capable of being independently specifiable from each other.

26. The method of claim 25, further comprising: selectively energizing the first and second emission regions to tune light output between the first spectral band and the second spectral band.

27. The method of claim 25, further comprising: independently and differently modulating the first and second electrical input signals to independently and differently encode the first light output from the first emission region and the second light output from the second emission region.

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