Lens, light source device having the lens, and device for estimating analyte concentration

Abstract

A lens is provided that outputs light emitted by a plurality of light sources with a uniform light distribution. The lens includes: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite to the first surface; and a plurality of incident surfaces recessed from the incident hole toward the second surface, each of the plurality of incident surfaces corresponding to a light source among the plurality of light sources.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10 - 2019 - 0112546, filed with the Korean Intellectual Property Office on September 11, 2019, the entire disclosure of which is incorporated herein by reference for all purposes. Technical field

[0003] Example embodiments of the present disclosure relate to a technique for outputting light emitted from a plurality of light sources with a uniform light distribution. Background art

[0004] Diabetes is a chronic disease that causes various complications and is difficult to cure. Therefore, it is recommended that diabetic patients regularly check their blood glucose to prevent complications. In particular, when insulin is administered to control blood glucose, it is necessary to closely monitor the blood glucose level to avoid hypoglycemia and control the insulin dose. An invasive method using finger pricking is generally used to measure the blood glucose level. However, although the invasive method can provide high measurement reliability, it may cause pain, inconvenience due to injection, and an increased risk of infection. Recently, research has been conducted on methods for accurately and non - invasively measuring blood glucose by using a spectrometer without blood sampling. Summary of the invention

[0005] Example embodiments provide a lens for outputting light emitted from a plurality of light sources with a uniform light distribution, a light source device using the lens, and a device for estimating analyte concentration.

[0006] According to an aspect of an example embodiment, there is provided a lens configured to output light emitted from a plurality of light sources with a uniform light distribution, the lens including: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite the first surface; and a plurality of incident surfaces recessed from the incident hole toward the second surface, each incident surface of the plurality of incident surfaces corresponding to a light source of the plurality of light sources.

[0007] The lens body may be made of a glass material or a plastic material.

[0008] Each of the plurality of incident surfaces may have the same conic constant.

[0009] Each of the plurality of incident surfaces may have an oblong elliptical shape.

[0010] The conic constant may be a value in the range of - 1.0 to - 0.2.

[0011] The optical axis of each light source of the plurality of light sources may pass through the vertex of the corresponding incident surface of the plurality of incident surfaces.

[0012] According to an aspect of an exemplary embodiment, a light source device is provided, including: a plurality of light sources configured to emit light; a plurality of waveguides through which the light emitted by the plurality of light sources passes; and a lens configured to output the light that has passed through the plurality of waveguides with a uniform light distribution, wherein the lens includes: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite to the first surface; and a plurality of incident surfaces recessed from the incident hole toward the second surface, each of the plurality of incident surfaces corresponding to a light source among the plurality of light sources.

[0013] The lens body may be made of a glass material or a plastic material.

[0014] Each of the plurality of incident surfaces may have the same conic constant.

[0015] Each of the plurality of incident surfaces may have an oblong elliptical shape.

[0016] The conic constant may be a value in the range of -1.0 to -0.2.

[0017] The optical axis of each light source among the plurality of light sources may pass through the vertex of the corresponding incident surface among the plurality of incident surfaces.

[0018] The plurality of waveguides may be optical fiber waveguides.

[0019] The plurality of waveguides may be accommodated in the incident hole.

[0020] According to an aspect of an exemplary embodiment, a light source device is provided, including: a plurality of light sources configured to emit light; and a lens configured to output the light emitted by the plurality of light sources with a uniform light distribution, wherein the lens includes: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite to the first surface; and a plurality of incident surfaces recessed from the incident hole toward the second surface, each of the plurality of incident surfaces corresponding to a light source among the plurality of light sources.

[0021] The lens body may be made of a glass material or a plastic material.

[0022] Each of the plurality of incident surfaces may have the same conic constant.

[0023] Each of the plurality of incident surfaces may have an oblong elliptical shape.

[0024] The conic constant may be a value in the range of -1.0 to -0.2.

[0025] The optical axis of each of the plurality of light sources may pass through the vertex of the corresponding incident surface among the plurality of incident surfaces.

[0026] The plurality of light sources may be accommodated in the incident holes.

[0027] According to an aspect of an example embodiment, there is provided an apparatus for estimating an analyte concentration, the apparatus including: a plurality of light sources configured to emit light; a plurality of waveguides through which the light emitted by the plurality of light sources passes; and a lens configured to output the light that has passed through the plurality of waveguides to an object with a uniform light distribution; a photodetector configured to detect light reflected or scattered from the object; and a processor configured to estimate the concentration of the analyte based on the detected light, wherein the lens includes: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite the first surface; and a plurality of incident surfaces recessed from the incident hole toward the second surface, each incident surface among the plurality of incident surfaces corresponding to a light source among the plurality of light sources.

[0028] The analyte may be at least one of glucose, triglyceride, urea, uric acid, lactate, protein, cholesterol, or ethanol. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] According to the following description with reference to the accompanying drawings, the above and / or other aspects, features, and advantages of certain example embodiments will become more apparent, in which:

[0030] Figure 1 is a diagram for explaining the optical path length when light is emitted at different distances from the photodetector;

[0031] Figure 2 is an example diagram showing the arrangement of a plurality of light sources according to an example embodiment;

[0032] Figure 3 is applied to Figure 2 a perspective view of a lens for the plurality of light sources shown;

[0033] Figure 4 is a sectional view of the lens taken along line a-b of Figure 3 according to an example embodiment; Figure 3 of the lens;

[0034] Figure 5 、 Figure 6 、 Figure 7 and Figure 8 are diagrams showing examples of a light source device to which a lens is applied;

[0035] Figure 9 and Figure 10 are diagrams showing Figure 5An example diagram of the output light distribution of each light source of the light source device 500;

[0036] Figure 11 is a block diagram showing a spectral measurement device according to an example embodiment;

[0037] Figure 12 、 Figure 13 and Figure 14 are diagrams explaining examples of reconstructing spectra;

[0038] Figure 15 and Figure 16 are diagrams explaining the concept of the net analyte signal (NAS) algorithm;

[0039] Figure 17 is a block diagram showing a device for estimating analyte concentration according to an example embodiment;

[0040] Figure 18 is a flowchart showing an example of a method for estimating analyte concentration;

[0041] Figure 19 is a flowchart showing another example of a method for estimating analyte concentration;

[0042] Figure 20 is a block diagram showing another example of a device for estimating analyte concentration; and

[0043] Figure 21 is a diagram showing an example of a wrist-worn wearable device. Detailed Description of the Embodiment

[0044] Hereinafter, example embodiments will be described in detail with reference to the accompanying drawings. In the following description, detailed descriptions of well-known functions and configurations included herein will be omitted when they may obscure the subject matter of the present disclosure.

[0045] Throughout the drawings and the detailed description, unless otherwise described, the same reference numerals will be understood to refer to the same elements, features, and structures. For clarity, illustration, and convenience, the relative dimensions of these elements may be exaggerated and drawn.

[0046] Unless a specified order is clearly stated in the context of the present disclosure, the process steps described herein may be performed in an order different from the specified order. That is, each step may be performed in the specified order, substantially simultaneously, or in the reverse order.

[0047] In addition, the terms used throughout this specification are defined in consideration of the functions according to the example embodiments, and may vary according to the purposes or precedents of users or managers, etc. Therefore, the terms should be defined based on the entire context.

[0048] It should be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Any reference to the singular may include the plural unless otherwise expressly stated. In this specification, it should be understood that terms such as "including" or "having" are intended to indicate the presence of features, numbers, steps, actions, components, parts, or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. As used herein, expressions such as "at least one of..." modify the entire list of elements when following the list of elements rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0049] In addition, the components to be described in the specification are distinguished only according to the functions mainly performed by the components. That is, two or more components to be described later may be integrated into a single component. In addition, a single component may be divided into two or more components. In addition, in addition to its main function, each component may additionally perform some or all of the functions performed by another component. Some or all of the main functions of each component may be implemented by another component. Each component may be implemented as hardware, software, or a combination of both.

[0050] Figure 1 is a diagram for explaining the optical path lengths when light is incident on portions at different distances from the photodetector.

[0051] As Figure 1 shown, the light of the first wavelength λ 1 incident on the first portion at the farthest distance from the photodetector PD travels the first optical path length l 1 , to be received by the photodetector PD; the light of the second wavelength λ 2 incident on the second portion at the second farthest distance from the photodetector PD travels the second optical path length l 2 , to be received by the photodetector PD; the light of the third wavelength λ 3 incident on the third portion at the third farthest distance from the photodetector PD travels the third optical path length l 3 , to be received by the photodetector PD; and the light of the fourth wavelength λ 4 incident on the fourth portion at the fourth farthest distance from the photodetector PD travels the fourth optical path length l 4, and is received by the photodetector PD. The optical path and the optical path length can vary according to the distance between the light incident portion and the photodetector PD, such that the optical signals incident on portions at different distances from the photodetector PD and received by the photodetector PD can include different information. Therefore, if these optical signals are used to estimate the analyte concentration (e.g., blood glucose, etc.), the accuracy of the estimation may be reduced.

[0052] Figure 2 is an exemplary diagram showing the arrangement of a plurality of light sources according to an exemplary embodiment; Figure 3 is applied according to an exemplary embodiment to Figure 2 a perspective view of a lens of the plurality of light sources shown; and Figure 4 is along according to an exemplary embodiment Figure 3 taken along line a-b of Figure 3 a cross-sectional view of the lens. Although for ease of explanation, Figure 2 , Figure 3 and Figure 4 show four light sources, this is merely an example, and the number and arrangement of the light sources are not limited thereto.

[0053] Referring to Figure 2 , Figure 3 and Figure 4 , in one exemplary embodiment, the plurality of light sources 211, 212, 213, and 214 can be arranged in a square, with each light source located at a vertex of the square.

[0054] Each of the light sources 211, 212, 213, and 214 can emit light of different wavelengths. In one exemplary embodiment, each of the light sources 211, 212, 213, and 214 can emit near-infrared (NIR) light or mid-infrared (MIR) light. However, the wavelength of the light emitted by each of the light sources 211, 212, 213, and 214 can vary according to the measurement purpose or the type of analyte. In addition, each of the light sources 211, 212, 213, and 214 does not necessarily consist of a single light emitter, but can be formed by an array of multiple light emitters. If each of the light sources 211, 212, 213, and 214 is formed by multiple light emitters, the multiple light emitters can emit light of the same wavelength or different wavelengths. Additionally, some of the multiple light emitters can emit light of the same wavelength, while other light emitters can emit light of different wavelengths. In the exemplary embodiment, each of the light sources 211, 212, 213, and 214 can include a light-emitting diode (LED), a laser diode, a phosphor, etc.

[0055] The lens 300 can output the light emitted by the light sources 211, 212, 213, and 214 with a uniform light distribution. In this case, outputting the light with a uniform light distribution can indicate that the output light is distributed at a uniformity level greater than or equal to a predetermined value.

[0056] The lens 300 includes a lens body 310, an incident hole 320, and a plurality of incident surfaces 330.

[0057] The lens body 310 may include a top surface 311 and a bottom surface 312. The top surface 311 forms the outer shape of the top of the lens body 310, and the bottom surface 312 forms the outer shape of the bottom of the lens body 310. The top surface 311 may be a curved surface with a curvature gradually increasing from the topmost center towards the edge, that is, a convex surface. The bottom surface 312 may be a flat surface.

[0058] In an exemplary embodiment, the lens body 310 may be made of a glass material, such as glass, borosilicate crown glass, etc., or made of a plastic material, such as polycarbonate, polymethyl methacrylate (PMMA), etc.

[0059] The incident hole 320 is formed on the bottom surface 312 such that the light emitted by the plurality of light sources 211, 212, 213, and 214 can be incident through the incident hole 320.

[0060] As Figure 3 shown, the incident hole 320 may be formed in a shape of four overlapping circles or ellipses, and the number thereof is equal to the number of light sources. However, the incident hole 320 is not limited thereto, and the incident hole 320 may be formed in various shapes according to the number or arrangement of the light sources used in the lens 300.

[0061] In an exemplary embodiment, the incident hole 320 may be formed at the center of the bottom surface 312 such that the center point of the incident hole 320 coincides with the center point of the bottom surface 312.

[0062] The incident surface 330 may be recessed from the incident hole 320 towards the inside of the lens 300, that is, towards the top surface 311.

[0063] In an exemplary embodiment, an incident surface 330 may be formed for each light source used in the lens 300. As shown herein, four incident surfaces 330 may be formed, and the number thereof is equal to the number of the light sources 211, 212, 213, and 214.

[0064] The surface profile (recess) of each incident surface 330 may be represented by Equation 1 below.

[0065] [Equation 1]

[0066]

[0067] Here, Z(s) represents the surface profile (depression) of a surface parallel to the optical axis; k represents the conic constant; s represents the radius of curvature; and C represents the curvature of 1 / s.

[0068] The surface profile (depression) with respect to the conic constant k is as follows.

[0069] Conic constant k Surface type k＝0 Sphere k＝-1 Parabola k<-1 Hyperbola -1<k<0 Oblate ellipse k>0 Prolate ellipse

[0070] In an exemplary embodiment, the incident surface 330 has the same conic constant k, which can be a value in the range of -1.0 to -0.2. That is, each incident surface 330 can be formed in an oblong elliptical shape.

[0071] As shown here, the incident surfaces 330 can overlap each other, but the embodiment is not limited thereto, and the incident surfaces 330 can be formed separately without overlapping each other.

[0072] In an exemplary embodiment, the optical axis of each light source among the plurality of light sources can pass through the vertex of the incident surface 330 corresponding to each light source among the plurality of light sources.

[0073] Hereinafter, examples of a light source device to which the lens 300 is applied will be described with reference to Figures 5 to 8 FIGs.

[0074] Figure 5 , Figure 6 , Figure 7 and Figure 8 are diagrams showing examples of a light source device to which the lens 300 is applied. Although Figure 5 , Figure 6 , Figure 7 and Figure 8 show examples of applying four light sources, two of the light sources will be omitted for ease of explanation.

[0075] Referring to Figure 5 , the light source device 500 includes a plurality of light sources 211 and 212, a plurality of waveguides 511 and 512, and a lens 300.

[0076] The light source 211 can be connected to the waveguide 511, and the light source 212 can be connected to the waveguide 512. That is, the light emitted by the light sources 211 and 212 can respectively pass through the waveguides 511 and 512 connected to the light sources 211 and 212, and enter the incident holes 320 of the lens 300. The light incident on the incident holes 320 can be incident on the incident surfaces 331 and 332. Each of the waveguides 511 and 512 includes an optical fiber and can be disposed outside the incident holes 320. In this case, the diameter of the incident holes 320 can be larger than the diameter of the beams of the waveguides 511 and 512.

[0077] Reference Figure 6 , the light source device 600 includes a plurality of light sources 211 and 212, a plurality of waveguides 511 and 512, and a lens 300.

[0078] The light source 211 can be connected to the waveguide 511, and the light source 212 can be connected to the waveguide 512. That is, the light emitted by the light sources 211 and 212 can pass through the waveguides 511 and 512 connected to the light sources 211 and 212 respectively, and be incident on the incident surfaces 331 and 332 of the lens 300. Each of the waveguides 511 and 512 includes an optical fiber, and a part of some or all of the waveguides 511 and 512 can be accommodated in the incident hole 320.

[0079] Reference Figure 7 , the light source device 700 includes a plurality of light sources 211 and 212 and a lens 300.

[0080] Different from Figure 5 and Figure 6 example, the light source device 700 does not include a waveguide, so that the light emitted by each of the light sources 211 and 212 can be directly incident on the incident hole 320 of the lens 300. The light incident on the incident hole 320 can be incident on the incident surfaces 331 and 332. Each of the light sources 211 and 212 can be arranged outside the incident hole 320. In this case, the diameter of the incident hole 320 can be larger than the diameter of the beams of the light sources 211 and 212.

[0081] Reference Figure 8 , the light source device 800 includes a plurality of light sources 211 and 212 and a lens 300. The light emitted by each of the light sources 211 and 212 can be directly incident on the incident surfaces 331 and 332 of the lens 300. Each of the light sources 211 and 212 can be arranged inside the incident hole 320.

[0082] Figure 9 and Figure 10 are example diagrams showing Figure 5 the output light distribution of each light source of the light source device 500. More specifically, Figure 9 is a diagram showing the output light distribution of the lens 300 when the light emitted by the light source 211 passes through the waveguide 511 and is incident on the lens 300; and Figure 10 is a diagram showing the output light distribution of the lens 300 when the light emitted by the light source 212 passes through the waveguide 512 and is incident on the lens 300.

[0083] Compare Figure 9 and Figure 10, as can be seen from their bottom views, it can be seen that the output light distribution is uniform and very similar in each case. Therefore, even when using multiple light sources, light can be uniformly emitted to an object by using the lens 300 according to the exemplary embodiment, thereby reducing the difference in the optical path or the optical path length caused by the position of the light source or the light incident portion.

[0084] Figure 11 is a block diagram showing a spectroscopic measurement device according to an exemplary embodiment. The spectroscopic measurement device 1100 is a device for measuring the in-vivo spectrum of an object, and can be included in an electronic device, or can be encapsulated in a housing to be provided as a separate device. In this case, examples of the electronic device may include a cellular phone, a smart phone, a tablet personal computer (PC), a laptop computer, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, an MP3 player, a digital camera, a wearable device, etc.; and examples of the wearable device may include a wristwatch-type wearable device, a wristband-type wearable device, a ring-type wearable device, a belt-type wearable device, a necklace-type wearable device, an ankle-band-type wearable device, a thigh-band-type wearable device, a forearm-band-type wearable device, etc. However, the electronic device is not limited to the above examples, and the wearable device is not limited to the above examples.

[0085] Referring Figure 11 , the spectroscopic measurement device 1100 includes a light source device 1110, a photodetector 1120, and a processor 1130. Here, the light source device 1110 can be any one of the light source devices 500, 600, 700, and 800 described above with reference Figures 5 to 10 and thus its detailed description will be omitted.

[0086] The photodetector 1120 can receive a light signal reflected or scattered from or transmitted into the object. The photodetector 1120 can convert the received light signal into an electrical signal and can send the signal to the processor 1130. In the exemplary embodiment, the photodetector 1120 can include a photodiode, a phototransistor (PTr), an image sensor (e.g., a charge-coupled device (CCD), a complementary metal oxide semiconductor (CMOS), etc.), and so on. The photodetector 1120 is not necessarily a single device, but can be formed by an array of multiple devices.

[0087] There can be various numbers and arrangements of the light source device and the photodetector, and their numbers and arrangements can vary according to the type of analyte and the purpose of use, the size and shape of the electronic device in which the spectroscopic measurement device 1100 is installed, etc. In addition, the spectroscopic measurement device 1100 can also include various optical elements (e.g., filters, mirrors, lenses, etc.).

[0088] Processor 1130 may process various signals and operations related to measuring in vivo spectra.

[0089] The processor 1130 may sequentially or simultaneously drive each light source of the light source device 1110 according to a predetermined control signal. In this case, the processor 1130 may drive each light source by referring to a predetermined light source driving condition. In this case, the light source driving condition may include the emission time, driving order, current intensity, pulse duration, etc. of each light source.

[0090] The processor 1130 may obtain an in vivo spectrum of the object based on the intensity of the light received by the photodetector 1120. Here, the in vivo spectrum may be an absorption spectrum, but is not limited thereto, and may be a reflection spectrum or a transmission spectrum. In an example embodiment, the processor 1130 may reconstruct an in vivo spectrum of the object based on the intensity of the light received by the photodetector 1120.

[0091] Figure 12 , Figure 13 and Figure 14 11 is a diagram explaining an example of reconstructing a spectrum by the processor 1130 .

[0092] refer to Figure 12 , Figure 13 and Figure 14 The light source device is composed of a light source array having N light sources; and each light source can be predetermined to have a peak wavelength λ based on the light source driving conditions. 1 , 2 , 3 , …, λ n .

[0093] The processor 1130 may sequentially drive each light source of the light source device to emit light based on a predetermined light source driving condition; and the photodetector may detect light returned from the object. In this case, the processor 1130 may only drive some of the light sources, and may divide the light sources into groups to drive each light source group in a time-division manner.

[0094] The processor 1130 can reconstruct the spectrum by receiving the optical signal from the photodetector, such as Figure 14 In this case, the processor 1130 may reconstruct the spectrum by using the following equation 2.

[0095] [Equation 2]

[0096] y α =(αE+A T A) -1 A T p

[0097] Here, α represents a parameter for spectral reconstruction, E represents the identity matrix, A represents the light source spectra measured for each light source, p represents the intensity of the optical signal detected by the photodetector, and y α represents the reconstructed spectrum. In this case, the light source spectra may refer to the spectra of the light emitted by each light source, and information about the light source spectra may be pre-stored in an internal or external database.

[0098] Figure 15 And Figure 16 are diagrams for explaining the concept of the net analyte signal (NAS) algorithm.

[0099] Refer to Figure 15 and Figure 16 , the net analyte signal (NAS) algorithm can learn spectral change factors that are not related to changes in analyte concentration by using in vivo spectra S 1 , S 2 , …, S n measured during the training interval as training data to generate an analyte concentration estimation model. In addition, the NAS algorithm can estimate analyte concentrations C n+1 , C n+2 , …, C m by using in vivo spectra S n+1 , S n+2 , …, S m measured during the estimation interval after the training interval and the concentration estimation model generated during the training interval. In this case, the training interval may be an interval in which the concentration of the analyte in vivo is substantially constant (for example, a fasting interval if the analyte is glucose).

[0100] That is, the NAS algorithm can generate a concentration estimation model based on in vivo spectra measured during the training interval, and then can estimate the analyte concentration by applying the generated concentration estimation model to the estimation interval.

[0101] Figure 17 is a block diagram showing a device for estimating an analyte concentration according to an exemplary embodiment. Figure 17 The device 1700 for estimating an analyte concentration is a device for estimating an analyte concentration by analyzing in vivo spectra of an object, and may be included in the aforementioned electronic device, or may be encapsulated in a housing to be provided as a separate device.

[0102] Refer to Figure 17 , the device 1700 for estimating an analyte concentration includes a light source device 1710, a photodetector 1720, and a processor 1730. Here, the light source device 1710 and the photodetector 1720 are related to Figure 11The light source device 1110 and the photodetector 1120 are the same as those described above, and thus their detailed descriptions will be omitted.

[0103] The processor 1730 may control the overall operation of the device 1700 for estimating the analyte concentration.

[0104] By using the light source device 1710 and the photodetector 1720, the processor 1730 may measure a plurality of in-vivo spectra (hereinafter referred to as in-vivo training spectra) in an interval where the analyte concentration of the subject is substantially constant, and may measure an in-vivo spectrum (hereinafter referred to as an in-vivo estimation spectrum) for estimating the analyte concentration of the subject.

[0105] The processor 1730 may generate a concentration estimation model based on the measured plurality of in-vivo training spectra. In this case, examples of the analyte may include glucose, triglyceride, urea, uric acid, lactate, protein, cholesterol, ethanol, etc., but the analyte is not limited thereto. When the in-vivo analyte is glucose, the analyte concentration may indicate the blood glucose level; and the interval where the concentration of the analyte is substantially constant may indicate a fasting interval during which the subject does not ingest glucose. Hereinafter, for the sake of convenience of explanation, glucose will be used as an example of the analyte to give the following description.

[0106] In an exemplary embodiment, the processor 1730 may generate a concentration estimation model by using the NAS algorithm and the plurality of in-vivo training spectra measured in the fasting interval. More specifically, the processor 1730 may use the plurality of in-vivo training spectra measured in the fasting interval as training data to learn the spectral change factors that are not related to the change in the analyte concentration. For example, the processor 1730 may extract the principal component spectral vectors from the plurality of in-vivo training spectra measured in the fasting interval by using various dimensionality reduction algorithms (e.g., principal component analysis (PCA), independent component analysis (ICA), non-negative matrix factorization (NMF), singular value decomposition (SVD), etc.). In addition, the processor 1730 may generate a concentration estimation model based on the training results (i.e., the extracted principal component spectral vectors). In this case, the generated concentration estimation model may be represented by Equations 3 and 4 below.

[0107] [Equation 3]

[0108]

[0109] [Equation 4]

[0110] C m = ΔC + C 0

[0111] Here, C m represents the analyte concentration, C 0represents a reference concentration of an analyte (e.g., the concentration of the analyte measured in a fasting state), ΔC represents a change in concentration compared to C 0 and S m represents an in vivo estimated spectrum, S pc，i represents a principal component spectrum, a i represents the contribution of each principal component spectrum to the in vivo estimated spectrum, ε g represents the spectrum of the analyte per unit concentration (e.g., 1 mM) (hereinafter referred to as the pure component spectrum), L represents the optical path length, where ε g can be obtained experimentally.

[0112] After generating a concentration estimation model and subsequently obtaining an in vivo estimated spectrum for estimating the analyte concentration, the processor 1730 can estimate the analyte concentration by using the in vivo estimated spectrum and the concentration estimation model. For example, the processor 1730 can calculate ΔC by applying a regression analysis algorithm (e.g., the least squares method) to Equation 3, and can estimate the analyte concentration by using Equation 4. During the process of calculating ΔC by applying the regression analysis algorithm, a i can also be calculated.

[0113] Figure 18 is a flowchart showing a method for estimating the analyte concentration according to an exemplary embodiment. It can be performed by Figure 17 the apparatus 1700 for estimating the analyte concentration Figure 18 to perform the method for estimating the analyte concentration.

[0114] Refer to Figure 18 , in operation 1810, the apparatus for estimating the analyte concentration can measure the in vivo estimated spectrum.

[0115] In operation 1820, the apparatus for estimating the analyte concentration can estimate the analyte concentration by using the in vivo estimated spectrum and a pre-generated concentration estimation model. For example, the apparatus for estimating the analyte concentration can calculate ΔC by applying a regression analysis algorithm to Equation 3, and can estimate the analyte concentration by using Equation 4. During the process of calculating ΔC by applying the regression analysis algorithm, a i can also be calculated.

[0116] Figure 19 is a flowchart showing a method for estimating the analyte concentration according to an exemplary embodiment. It can be performed by Figure 17 the apparatus 1700 for estimating the analyte concentration Figure 19 to perform the method for estimating the analyte concentration.

[0117] Refer to Figure 19, in operation 1910, a device for estimating analyte concentration may measure a plurality of in-vivo training spectra during an interval in which the analyte concentration of the subject is substantially constant.

[0118] In operation 1920, a device for estimating analyte concentration may generate a concentration estimation model based on the plurality of measured in-vivo training spectra. In this case, examples of analytes may include glucose, triglycerides, urea, uric acid, lactate, proteins, cholesterol, ethanol, etc., but analytes are not limited thereto. When the in-vivo analyte is glucose, the analyte concentration may indicate the blood glucose level; and the interval in which the concentration of the analyte is substantially constant may indicate a fasting interval during which the subject does not ingest glucose.

[0119] In one exemplary embodiment, a device for estimating analyte concentration may generate a concentration estimation model by using the NAS algorithm and a plurality of in-vivo training spectra. More specifically, a device for estimating analyte concentration may learn spectral change factors that are not related to changes in analyte concentration by using a plurality of in-vivo training spectra as training data. For example, a device for estimating analyte concentration may extract principal component spectral vectors from a plurality of in-vivo training spectra by using various dimensionality reduction algorithms. Additionally, a device for estimating analyte concentration may generate a concentration estimation model based on the results of the training (i.e., the extracted principal component spectral vectors). In this case, the generated concentration estimation model may be represented by Equations 3 and 4 above.

[0120] In operation 1930, a device for estimating analyte concentration may measure an in-vivo estimation spectrum, and in operation 1940, a device for estimating analyte concentration may estimate the analyte concentration by using the in-vivo estimation spectrum and the concentration estimation model.

[0121] Figure 20 is a block diagram showing a device for estimating analyte concentration according to an exemplary embodiment. Figure 20 The device 2000 for estimating analyte concentration is a device for estimating analyte concentration by analyzing the in-vivo spectrum of a subject, and may be included in the aforementioned electronic device, or may be encapsulated in a housing to be provided as a separate device.

[0122] Reference Figure 20 , the device 2000 for estimating analyte concentration includes a light source device 1710, a photodetector 1720, a processor 1730, an input interface 2010, a storage device 2020, a communication interface 2030, and an output interface 2040. Here, the light source device 1710, the photodetector 1720, and the processor 1730 are described above, and thus their detailed descriptions will be omitted. Figure 17

[0123] ​The input interface 2010 can receive inputs of various operation signals from a user. In one exemplary embodiment, the input interface 2010 can include one or more of a keypad, a dome switch, a touchpad (static pressure / capacitance), a roller, a microswitch, a hardware (H / W) button, etc. In particular, a touchpad that forms a layer structure with a display can be referred to as a touch screen.

[0124] The storage device 2020 can be a memory configured to store programs or commands for operating the device 2000 for estimating analyte concentration, and can store data input to and processed by the device 2000 for estimating analyte concentration. In addition, the storage device 2020 can store in vivo spectra, concentration estimation models, estimated analyte concentration values, etc. The storage device 2020 can include at least one of the following storage media: flash memory type, hard disk type, multimedia card micro memory, card type memory (e.g., SD memory, XD memory, etc.), random access memory (RAM), static random access memory (SRAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), programmable read only memory (PROM), magnetic memory, magnetic disks, and optical disks, etc. In addition, the device 2000 for estimating analyte concentration can operate an external storage medium, such as a network storage device, etc., which performs the storage function of the storage device 2020 on the Internet.

[0125] The communication interface 2030 can communicate with an external device. For example, the communication interface 2030 can send data input to the device 2000 for estimating analyte concentration, data stored in and processed by the device 2000 for estimating analyte concentration, etc. to the external device, or can receive various data that can be used for estimating analyte concentration from the external device.

[0126] In this case, the external device can be a medical device that uses data input to the device 2000 for estimating analyte concentration, data stored in and processed by the device 2000 for estimating analyte concentration, etc., a printer for printing out results, or a display for displaying results. Additionally, the external device can be a digital TV, a desktop computer, a cellular phone, a smart phone, a tablet PC, a laptop computer, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, an MP3 player, a digital camera, a wearable device, etc., but is not limited thereto.

[0127] The communication interface 2030 can communicate with external devices by using one or more of the following: Bluetooth communication, Bluetooth Low Energy (BLE) communication, Near Field Communication (NFC), WLAN communication, Zigbee communication, Infrared Data Association (IrDA) communication, Wi-Fi Direct (WFD) communication, Ultra-Wideband (UWB) communication, Ant+ communication, WiFi communication, Radio Frequency Identification (RFID) communication, 3G communication, 4G communication, 5G communication, etc. However, this is only an example and is not intended to be limiting.

[0128] The output interface 2040 can output: data input to the device 2000 for estimating analyte concentration, data stored in and processed by the device 2000 for estimating analyte concentration, etc. In one exemplary embodiment, the output interface 2040 can output: data input to the device 2000 for estimating analyte concentration, data stored in and processed by the device 2000 for estimating analyte concentration, etc. by using at least one of an acoustic method, a visual method, and a tactile method. To this end, the output interface 2040 can include a display, a speaker, a vibrator, etc.

[0129] Figure 21 is a diagram showing an example of a wrist-worn wearable device.

[0130] Reference Figure 21 , the wrist-worn wearable device 2100 includes a band 2110 and a body 2120.

[0131] The band 2110 can be connected to both ends of the body 2120 so as to be fastened in a detachable manner, or can be integrally formed with the body 2120 as a smart band. The band 2110 can be made of a flexible material to wrap around the user's wrist so that the body 2120 can be worn on the wrist.

[0132] The body 2120 can include the aforementioned spectral measurement device 1100 and / or the aforementioned devices 1700 and 2000 for estimating analyte concentration. In addition, the body 2120 can include a battery that supplies power to the spectral measurement device 1100 and the devices 1700 and 2000 for estimating analyte concentration.

[0133] The light source devices 500, 600, 700, and 800 can be provided on the bottom of the body 2120 to be exposed to the user's wrist. Thus, when the user wears the wrist-worn wearable device 2100, the light source devices 500, 600, 700, and 800 can naturally come into contact with the user's skin. In this case, the light source devices 500, 600, 700, and 800 can emit light to the object.

[0134] The wrist-worn wearable device 2100 may further include a display 2121 and an input interface 2122 mounted in the main body 2120. The display 2121 may display data processed by the spectral measurement device 1100, the devices 1700 and 2000 for estimating analyte concentration, and / or the wrist-worn wearable device 2100, its processed result data, and the like. The input interface 2122 may receive various operation signals from the user.

[0135] Embodiments of the present disclosure may be implemented as computer-readable code stored on a non-transitory computer-readable recording medium and executed by a processor. Codes and code segments required to implement embodiments of the present disclosure may be easily deduced by ordinary computer programmers in the art. The computer-readable recording medium may be any type of recording device that stores data in a computer-readable manner. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical disk, and the like. In addition, the computer-readable recording medium may be distributed over multiple computer systems connected to a network, such that the computer-readable recording medium is written therein and executed therefrom in a distributed manner.

[0136] Example embodiments have been described herein. However, it will be apparent to those skilled in the art that various modifications can be made without departing from the inventive concept. Therefore, it should be understood that the scope of the present disclosure is not limited to the above embodiments, but is intended to include various modifications and equivalents encompassed within the spirit and scope of the appended claims.

Claims

1. A lens configured to output light emitted by a plurality of aligned light sources with a uniform light distribution, the lens comprising: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite to the first surface; and a plurality of incident surfaces recessed from the incident hole toward the first surface, wherein each of the plurality of incident surfaces corresponds to a respective one of the plurality of light sources, and wherein the incident hole is formed by a plurality of overlapping circles or ellipses, and the number of the plurality of overlapping circles or ellipses is equal to the number of the plurality of light sources.

2. The lens according to claim 1, wherein the lens body is made of a glass material or a plastic material.

3. The lens according to claim 1, wherein each of the plurality of incident surfaces has the same conic constant.

4. The lens according to claim 3, wherein each of the plurality of incident surfaces has an oblong elliptical shape.

5. The lens according to claim 4, wherein the conic constant is a value in the range of -1.0 to -0.

2.

6. The lens according to claim 1, wherein the optical axis of each of the plurality of light sources passes through the vertex of the incident surface corresponding to the light source among the plurality of incident surfaces.

7. A light source device, comprising: a plurality of aligned light sources configured to emit light; a plurality of waveguides through which the light emitted by the plurality of light sources passes; and a lens configured to output the light that has passed through the plurality of waveguides with a uniform light distribution, wherein the lens comprises: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite to the first surface; and a plurality of incident surfaces recessed from the incident hole toward the first surface, wherein each of the plurality of incident surfaces corresponds to a respective one of the plurality of light sources, and wherein the incident hole is formed by a plurality of overlapping circles or ellipses, and the number of the plurality of overlapping circles or ellipses is equal to the number of the plurality of light sources.

8. The light source device according to claim 7, wherein the lens body is made of a glass material or a plastic material.

9. The light source device according to claim 7, wherein each of the plurality of incident surfaces has the same conic constant.

10. The light source device according to claim 9, wherein each of the plurality of incident surfaces has an oblong elliptical shape.

11. The light source device according to claim 10, wherein the conic constant is a value in the range of -1.0 to -0.

2.

12. The light source device according to claim 7, wherein the optical axis of each of the plurality of light sources passes through the vertex of the incident surface corresponding to the light source among the plurality of incident surfaces.

13. The light source device according to claim 7, wherein the plurality of waveguides are optical fiber waveguides.

14. The light source device according to claim 7, wherein the plurality of waveguides are received in the incident hole.

15. A light source device, comprising: a plurality of aligned light sources configured to emit light; and a lens configured to output the light emitted by the plurality of light sources with a uniform light distribution, wherein the lens comprises: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite to the first surface; and a plurality of incident surfaces recessed from the incident hole toward the first surface, wherein each of the plurality of incident surfaces corresponds to a respective one of the plurality of light sources, and wherein the incident hole is formed by a plurality of overlapping circles or ellipses, and the number of the plurality of overlapping circles or ellipses is equal to the number of the plurality of light sources.

16. The light source device according to claim 15, wherein the lens body is made of a glass material or a plastic material.

17. The light source device according to claim 15, wherein each of the plurality of incident surfaces has the same conic constant.

18. The light source device according to claim 17, wherein each of the plurality of incident surfaces has an oblong elliptical shape.

19. The light source device according to claim 18, wherein the conic constant is a value in the range of -1.0 to -0.

2.

20. The light source device according to claim 15, wherein the optical axis of each of the plurality of light sources passes through the vertex of the incident surface corresponding to the light source among the plurality of incident surfaces.

21. The light source device according to claim 15, wherein the plurality of light sources are accommodated in the incident hole.

22. A device for estimating analyte concentration, the device comprising: a plurality of aligned light sources configured to emit light; a plurality of waveguides through which the light emitted by the plurality of light sources passes; and a lens configured to output the light that has passed through the plurality of waveguides to an object with a uniform light distribution; a photodetector configured to detect the light reflected or scattered from the object; and a processor configured to estimate the concentration of the analyte based on the detected light, wherein the lens comprises: a lens body having a flat first surface formed with an incident hole and a convex second surface opposite to the first surface; and a plurality of incident surfaces recessed from the incident hole toward the first surface, wherein each of the plurality of incident surfaces corresponds to a respective one of the plurality of light sources, and wherein the incident hole is formed by a plurality of overlapping circles or ellipses, and the number of the plurality of overlapping circles or ellipses is equal to the number of the plurality of light sources.

23. The device according to claim 22, wherein the analyte is at least one of glucose, triglyceride, urea, uric acid, lactate, protein, cholesterol or ethanol.

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