Noninvasive glucometer and design method thereof

Abstract

The invention provides a noninvasive glucometer which comprises a light source, a detector and an optical system, emergent light of the light source is reflected by a to-be-detected part of a human body and then is emitted towards the optical system, the optical system is located on the light incident side of the detector, and the detector is used for sensing the emergent light of the optical system. The optical system comprises a first optical element, the first optical element is configured to diffract incident light so as to enable emergent light of the optical system to irradiate different positions of the detector, and the first optical element is configured to be a metasurface; the first optical element in the optical system is configured to be the metasurface, compared with a traditional optical element, the metasurface of the sub-wavelength structure can reduce the size of the optical system, and miniaturization of the noninvasive glucometer is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of medical testing, and in particular to a non-invasive blood glucose meter and a design method for the non-invasive blood glucose meter. Background Art

[0002] Blood glucose concentration is an important indicator of diabetes status. Frequent blood glucose measurement helps monitor the condition and maintain normal blood glucose levels. Blood glucose testing methods are categorized as invasive, minimally invasive, and non-invasive. Invasive and minimally invasive methods have been put into clinical use due to their high accuracy. However, these methods often cause pain and discomfort to patients due to the need for blood sampling, carry the risk of infection, and are expensive per measurement. Consequently, non-invasive blood glucose testing technology has garnered widespread attention.

[0003] In related technologies, non-invasive blood glucose meters utilize the optical rotation properties of glucose to detect blood glucose concentrations. Specifically, they utilize a detector to sense reflected light from the body part to be measured. To better enable the detector to sense the reflected light from the body part to be measured, the non-invasive blood glucose meter is also equipped with an optical system to modulate the reflected light from the body part to be measured. However, these optical systems typically utilize traditional optical components, resulting in a large size and hindering the miniaturization of non-invasive blood glucose meters. Summary of the Invention

[0004] The object of the present invention is to provide a non-invasive blood glucose meter that is conducive to miniaturization and a design method for the non-invasive blood glucose meter.

[0005] To achieve one of the above-mentioned objectives, the present invention provides a non-invasive blood glucose meter in one embodiment, comprising:

[0006] light source;

[0007] detector;

[0008] An optical system, wherein the light emitted by the light source is reflected by the part of the human body to be measured and then emitted toward the optical system, the optical system is located on the light incident side of the detector, and the detector is used to sense the light emitted by the optical system;

[0009] The optical system includes a first optical element, which is configured to diffract incident light so that outgoing light of the optical system is irradiated at different positions of the detector, and the first optical element is configured as a metasurface.

[0010] As a further improvement of an embodiment of the present invention, the first optical element is configured to diffract incident light, specifically including:

[0011] The first optical element is configured to perform wavelength separation and / or polarization state separation on the incident light.

[0012] As a further improvement of one embodiment of the present invention, the first optical element has a first phase and a second phase, the first phase is configured to diffract the incident light, and the second phase is configured to modulate the incident light so that the outgoing light of the optical system converges at different positions of the detector.

[0013] As a further improvement of one embodiment of the present invention, the optical system includes a second optical element located on the light incident side of the first optical element, and the second optical element is configured to modulate the incident light to reduce the incident angle of at least part of the incident light incident on the first optical element.

[0014] As a further improvement of one embodiment of the present invention, the second optical element is configured as a metasurface or a traditional lens, and the first optical element and the second optical element are arranged separately.

[0015] As a further improvement of an embodiment of the present invention, the optical system further includes a first optical component located on the light-emitting side of the first optical element, and the first optical component is configured to converge the emergent light of the first optical element.

[0016] As a further improvement of an embodiment of the present invention, the optical system further includes a fourth optical element located on the light incident side of the detector, and the fourth optical element is configured as a filter element or a polarization element.

[0017] As a further improvement of an embodiment of the present invention, the output light of the light source is configured to be in a single polarization state, and the polarization direction of the output light of the light source is dynamically adjustable.

[0018] As a further improvement of an embodiment of the present invention, the output light of the light source includes at least a first wavelength band and a second wavelength band, and the first wavelength band and the second wavelength band are both configured as working wavelength bands of the optical system.

[0019] As a further improvement of an embodiment of the present invention, the output light of the light source includes a fourth wavelength band, and the difference between the working wavelength band of the optical system and the fourth wavelength band is the Raman characteristic shift.

[0020] As a further improvement of an embodiment of the present invention, the detector is configured as a CMOS sensor or a photodiode.

[0021] To achieve one of the objectives of the above invention, the present invention further provides a design method of the above non-invasive blood glucose meter, characterized in that it includes the following steps:

[0022] Determine the working band of the optical system according to the wavelength of the light emitted by the light source;

[0023] Based on the working band of the optical system, the first optical element is designed accordingly to irradiate the output light of the optical system at different positions of the detector;

[0024] Determine the optical signal that the detector needs to sense based on the output light of the optical system

[0025] As a further improvement of an embodiment of the present invention, an optical system is designed accordingly according to the parameters of the detector, so that the detector can sense polarization images formed at different positions.

[0026] As a further improvement of an embodiment of the present invention, an optical system is designed accordingly according to the parameters of the detector, so that the detector can sense spectral information and polarization information at different positions.

[0027] Compared with the prior art, in an embodiment of the present invention, the first optical element in the optical system is configured as a metasurface. Compared with traditional optical elements, the metasurface with a subwavelength structure can reduce the volume of the optical system, which is conducive to the miniaturization of the non-invasive blood glucose meter. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the optical path of the first and second embodiments of the non-invasive blood glucose meter of the present invention;

[0029] Figure 2 1 is a schematic diagram of the optical path of the third embodiment of the non-invasive blood glucose meter of the present invention;

[0030] Figure 3 1 is a schematic diagram of the optical path of the optical system in the fourth embodiment of the non-invasive blood glucose meter of the present invention;

[0031] Figure 4 1 is a schematic diagram of the optical path of the fifth embodiment of the non-invasive blood glucose meter of the present invention;

[0032] Figure 5 yes Figure 4 A plan view of the fourth optical element;

[0033] Figure 6 1 is a schematic diagram of the optical path of the sixth embodiment of the non-invasive blood glucose meter of the present invention;

[0034] Figure 7 yes Figure 6 Schematic diagram of the microlens array;

[0035] Figure 8 yes Figure 3 The polarization image formed by the optical system on the detector target surface;

[0036] Figure 9 This is a real picture of the non-invasive blood glucose meter of the present invention and the polarization image sensed during the measurement process;

[0037] Figure 10 This is the effect image after cutting, registering and correcting the distortion of the polarization image;

[0038] Figure 11 It is the polarization image of the light source using a single band and multiple bands;

[0039] Figure 12 It is the polarization image in a single band obtained by the spectral reconstruction algorithm and the polarization image after spectral fusion;

[0040] Figure 13 The spectral information and polarization information sensed by the detector are shown;

[0041] Figure 14 Results obtained by calculation as well as actual blood test results are shown. DETAILED DESCRIPTION

[0042] The present invention will be described in detail below with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0043] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0044] In the various drawings of the present invention, for the sake of convenience, some sizes of structures or parts are exaggerated relative to other structures or parts, and thus, only the basic structure of the subject matter of the present invention is illustrated.

[0045] refer to Figure 1 As shown, a first embodiment of the present invention provides a non-invasive blood glucose meter, which includes a light source 10 , a detector 20 and an optical system 30 .

[0046] In this embodiment, the light source 10 includes but is not limited to LED, EEL, VCSEL, fiber laser, or natural light. The detector 20 can convert the received light signal (eg, the light signal emitted by the optical system 30) into an electrical signal.

[0047] In some embodiments, the light emitted by the light source 10 is reflected by the part to be measured 40 of the human body and then emitted toward the optical system 30 .

[0048] In this embodiment, Figure 1When using the non-invasive blood glucose meter, the user places the body part 40 to be tested (such as the palm, finger, or eyeball, etc.) on the light-emitting side of the light source 10. The light emitted by the light source 10 irradiates the body part 40 to be tested and is reflected by the body part 40 to be tested to the optical system 30.

[0049] In some embodiments, the optical system 30 is located on the light incident side of the detector 20 , and the detector 20 is used to sense the outgoing light of the optical system 30 .

[0050] In this embodiment, the optical system 30 modulates the reflected light from the human body part 40 to be tested and then emits it to the detector 20. After the light signal emitted by the optical system 30 is sensed by the detector 20, the blood glucose concentration (such as the blood glucose concentration in the blood) can be determined.

[0051] For example, when light passes through a medium containing glucose (such as skin or aqueous humor), the polarization plane of the light rotates (i.e., Faraday effect or natural optical rotation), and the optical rotation angle (i.e., the shift in the polarization angle AoP) α is proportional to the glucose concentration C:

[0052] α=R(λ,T)·C·L

[0053] Where R is the optical rotation of glucose (related to wavelength λ and temperature T), and L is the optical path length.

[0054] It can be seen that by utilizing the chiral structure and optical activity of glucose molecules, the blood glucose concentration (such as the blood glucose concentration) can be determined by the light signal sensed by the detector 20 (i.e. the light signal reflected by the human body part 40 to be tested).

[0055] In some embodiments, the optical system 30 includes a first optical element 301. In this embodiment, Figure 1 The optical system 30 is composed only of the first optical element 301, for example, only of a metasurface, which minimizes the volume of the optical system 30 and thus can reduce the volume of the non-invasive blood glucose meter.

[0056] In some embodiments, the first optical element 301 is configured to diffract incident light so that the outgoing light of the optical system 20 is irradiated at different positions of the detector 20 .

[0057] In this embodiment, incident light (i.e., the light signal reflected from the human body part 40 to be measured) is diffracted after passing through the first optical element 301. Specifically, the first optical element 301 splits the light signal reflected from the human body part 40 to be measured, and the diffracted light is emitted to different positions on the sensing surface of the detector 20. The light signals sensed at different positions on the detector 20 are used to determine the blood glucose concentration (e.g., the blood glucose concentration).

[0058] In some embodiments, the first optical element 301 is configured as a metasurface.

[0059] In this embodiment, a metasurface refers to an artificial layered material with dimensions smaller than or approximately equal to the wavelength, which can be considered the two-dimensional counterpart of a metamaterial. Metasurfaces can manipulate the polarization, phase, amplitude, frequency, and propagation mode of electromagnetic waves through subwavelength metastructure units on their surface, enabling properties such as beam shaping, beam deflection, superlenses, superholography, optical rotation, and anti-reflection and anti-reflection.

[0060] In this embodiment, the metasurface is a sub-wavelength optical element, which is suitable for the current micron-scale detector architecture. At the same time, its preparation process is compatible with mature semiconductor detector technology and has strong practicality and economy.

[0061] In this embodiment, the first optical element 301 in the optical system 30 is configured as a metasurface. Compared with traditional optical elements, the metasurface with a subwavelength structure can reduce the volume of the optical system, which is conducive to the miniaturization of the non-invasive blood glucose meter.

[0062] In this embodiment, the metasurface includes a plurality of array-arranged metastructure units, each of which has a nanostructure 3012 at its center and / or vertex. The metasurface is divided into structural units centered on each nanostructure 3012. Multiple nanostructures 3012 are arranged on a substrate 3011, wherein the nanostructures 3012 in each period constitute a metastructure unit. The metastructure unit is a densely packed shape, such as a regular quadrilateral, a regular hexagon, a fan, etc., each period contains a nanostructure 3012, and the vertex and / or center of the metastructure unit can be provided with a nanostructure 3012. In the case where the metastructure unit is a regular hexagon, at least one nanostructure 3012 is provided at each vertex and center of the regular hexagon. Similarly, the same is true for fan-shaped and square shapes.

[0063] In this embodiment, the multiple superstructure units of the metasurface are arranged periodically or aperiodically. A periodic arrangement means that the period values ​​of the superstructure units are equal. An aperiodic arrangement means that the period values ​​of the superstructure units are at least partially different, where the different period values ​​can be different radial period values ​​and / or circumferential period values, or different period values ​​in the X-axis direction and / or the Y-axis direction.

[0064] In this embodiment, the nanostructure 3012 is configured as a polarization-dependent structure or a polarization-independent structure. Depending on the usage scenario, the nanostructure 3012 can be configured as either a polarization-dependent or polarization-independent structure. Examples of polarization-independent structures include cylindrical shapes, square cylindrical shapes, cross cylindrical shapes, and square cylindrical shapes with circular holes. Examples of polarization-dependent structures include elliptical cylindrical shapes, rectangular cylindrical shapes, and hexagonal prisms. The nanostructure 3012 can be either a positive or negative structure. For example, the shapes of the nanostructure 3012 include cylindrical shapes, hollow cylindrical shapes, square prisms, and hollow square prisms.

[0065] Specifically, the refractive index of substrate 3011 is lower than that of nanostructure 3012. Substrate 3011 can be made of any material with a low refractive index and absorption coefficient in the visible or near-infrared bands, such as silicon dioxide (SiO2), spin-on glass (SOG), or polymers such as polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polymethylpentene (PMP), and combinations thereof. Nanostructure 3012 can be made of a dielectric material with a higher refractive index than substrate 3011, such as c-Si, polycrystalline silicon (p-Si), amorphous silicon (a-Si), compound semiconductors (such as GaN, GaP, GaAs, SiC, etc.), TiO2, Si3N4, AlSb, AlAs, AlGaAs, AlGaInP, BP, ZnGeP2, and other suitable materials, as well as combinations thereof. The metasurface also includes a protective layer covering the nanostructure 3012. The material of the protective layer is similar to that of the substrate 3011 and can be any material with a low refractive index and absorption coefficient in the visible light or near-infrared band, such as: silicon dioxide (SiO2), spin-on glass (SOG), or polymers such as polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polymethylpentene (PMP) and combinations of the above materials, or air (i.e., no protective layer is set).

[0066] In some embodiments, the first optical element 301 is configured to diffract incident light, specifically including:

[0067] The first optical element 301 is configured to perform wavelength separation and / or polarization state separation on the incident light.

[0068] In this embodiment, the first optical element 301 splits the light signal reflected by the human body's tested part 40 into light signals of different wavelengths and / or polarization states, making it easier for the detector 20 to sense the light signal of a specific wavelength and / or a specific polarization state, which is beneficial for calculating and determining the blood glucose concentration (for example, the blood glucose concentration in the blood).

[0069] In this embodiment, the outgoing light after splitting by the first optical element 301 (i.e., the light signal reflected by the human body part to be measured 40) is emitted to different positions of the sensing surface of the detector 20, that is, the light signal of a specific wavelength and / or a specific polarization state is emitted to a specific position of the sensing surface of the detector 20, reducing the influence of other non-specific wavelengths and / or non-specific polarization states on the sensing of the detector 20, making it easier for the detector 20 to sense the light signal of a specific wavelength and / or a specific polarization state, which is beneficial to calculate and determine the blood glucose concentration (for example, the blood glucose concentration in the blood).

[0070] Among them, the metasurface can precisely control the phase and polarization through subwavelength structures, and achieve modulation goals more conveniently without adding additional optical devices.

[0071] For example, the first optical element 301 (i.e., the metasurface) is configured as a metagrating to achieve wavelength separation of the incident light (i.e., the light signal reflected from the human body part 40 to be tested). The nanostructure of the first optical element 301 (i.e., the metasurface) is configured as a polarization-dependent structure to achieve polarization state separation of the incident light (i.e., the light signal reflected from the human body part 40 to be tested).

[0072] In some embodiments, the first optical element 301 has a first phase and a second phase. In this embodiment, the first optical element 301 superimposes two phases (i.e., the first phase and the second phase), and the first optical element 301 implements two different modulation functions through the two phases. Compared to achieving two modulation functions using two metasurfaces, this approach can make the optical system 30 more compact and smaller.

[0073] For example, Figure 1 The nanostructures 3012 corresponding to the first phase and the nanostructures 3012 corresponding to the second phase are located on the same side of the substrate 3011. In other embodiments, the nanostructures 3012 corresponding to the first phase and the nanostructures 3012 corresponding to the second phase may also be located on opposite sides of the substrate 3011.

[0074] In some embodiments, the first phase is configured to diffract incident light. In this embodiment, the first optical element 301 utilizes the first phase to implement diffraction modulation (ie, beam splitting function), for example, the phase of a metagrating.

[0075] In some embodiments, the second phase is configured to modulate the incident light so that the light emitted by the optical system 30 converges at different locations on the detector 20. In this embodiment, after the first optical element 301 uses the second phase to achieve convergence modulation (i.e., achieve a focusing function), the light beams at different locations on the detector 20 are more concentrated, which is beneficial for the detection of light signals by the detector 20.

[0076] Exemplarily, the first phase can be configured as a metagrating phase, and the second phase can be configured as a metalens phase, and the two phases are superimposed to form a monolithic multi-focal vector metalens.

[0077] In some embodiments, the light emitted by the light source 10 is configured to have a single polarization state.

[0078] In this embodiment, light source 10 outputs light of a single polarization state. After reflection from the human body part 40, the polarization plane of the light rotates, but the light remains in a single polarization state. This simplifies the design of optical system 30 by eliminating the need to separate the polarization states of the incident light. Furthermore, it reduces the impact of light of other polarization states on the detection of detector 20.

[0079] Exemplarily, light source 10 is configured as a narrowband light source to minimize interference with blood glucose concentration detection caused by light from other wavelengths. For example, the wavelength of light emitted by light source 10 may be around 940 nm, as glucose exhibits strong optical rotation at 940 nm. Light emitted by light source 10 may be linearly polarized or circularly polarized.

[0080] In some embodiments, the polarization direction of the light emitted by the light source 10 is dynamically adjustable.

[0081] In this embodiment, the polarization direction of the light emitted by the light source 10 is dynamically adjusted according to the skin characteristics (such as thickness and pigment content) of different users, so as to penetrate the epidermis and focus on the capillary area of ​​the dermis.

[0082] Exemplarily, the excitation polarization state of the light source 10 is dynamically adjusted by a piezoelectric ceramic or liquid crystal polarizer.

[0083] In some embodiments, the detector 20 is configured as a CMOS sensor.

[0084] In this embodiment, the optical system 30 (or first optical element 301) diffracts the light signal reflected from the human body part 40 to form polarization images (e.g., sub-images with different polarization states or polarization directions) at different locations on the detector 20. A CMOS sensor (Complementary Metal Oxide Semiconductor) senses each polarization image to detect the blood glucose concentration (e.g., the blood glucose concentration).

[0085] Continue to refer Figure 1As shown, a second embodiment of the present invention provides a non-invasive blood glucose meter. In this non-invasive blood glucose meter, the light source 10 is configured as a broadband light source, which can distinguish and determine blood glucose from other optically active substances, thereby improving the accuracy of blood glucose concentration detection. In this embodiment, the same reference numerals represent the same components with similar functions and are not further described.

[0086] In some embodiments, the light emitted by the light source 10 includes at least a first wavelength band and a second wavelength band.

[0087] In this embodiment, it is considered that other optically active substances in the skin or aqueous humor (e.g., albumin and collagen) may also cause polarization rotation, leading to cross-interference and affecting the accuracy of the blood glucose meter. By configuring the output light of the light source 10 to include multiple wavelengths, the different optical rotations and birefringence coefficients of glucose and protein at different wavelengths can be utilized to distinguish and determine the difference between glucose and other optically active substances.

[0088] For example, since glucose has a strong optical rotation at 940 nm, the first wavelength band may be located near 940 nm. Since protein has more significant birefringence in the near-infrared wavelength band (such as 860 nm), the second wavelength band may be located near 860 nm.

[0089] In some embodiments, the light emitted by the light source 10 further includes a third wavelength band (eg, around 900 nm) to further distinguish the content of glucose and protein.

[0090] Exemplarily, the light source 10 is a broadband light source, covering the aforementioned multiple wavelength bands, for example, the first wavelength band and the second wavelength band, or the first wavelength band, the second wavelength band, and the third wavelength band. The spectral range can be any one or more different wavelength bands between the visible light band (380nm-750nm) and the near-infrared band (750nm-2500nm).

[0091] In some embodiments, the first wavelength band and the second wavelength band are both configured as working wavelength bands of the optical system 30 .

[0092] In this embodiment, the first band and the second band are both configured as the working bands of the optical system 30, which means that the optical system 30 has a higher efficiency (such as transmittance) for the incident light of the first band and the incident light of the second band, while it can have a relatively lower efficiency for other bands (such as non-working bands), and can filter out some other bands to a certain extent.

[0093] Similarly, the third wavelength band can also be configured as the working wavelength band of the optical system 30. In this case, the optical system 30 has high efficiency (such as transmittance) for the incident light in the first wavelength band, the incident light in the second wavelength band, and the incident light in the third wavelength band.

[0094] For example, under the premise of satisfying the phase, the metasurface, when performing phase arrangement, selects different parameters such as the superstructure unit period, nanostructure characteristic size, and nanostructure height, so that the metasurface has a higher efficiency for incident light in the working band (e.g., the first band, the second band, and the third band). During this selection process, the metasurface can also have a lower efficiency for incident light in other bands (e.g., non-working bands), thereby filtering out optical signals in other bands (e.g., non-working bands) and playing a filtering role. That is, the wavelength selection characteristics of the metasurface are utilized.

[0095] refer to Figure 2 As shown, a third embodiment of the present invention provides a non-invasive blood glucose meter. In this non-invasive blood glucose meter, the detector 20 is configured as a photodiode, which simplifies the structure of the detector 20 and reduces the manufacturing cost of the non-invasive blood glucose meter. In this embodiment, the same reference numerals represent the same components with similar functions and are not further described.

[0096] In some embodiments, the output light of the light source 10 includes a fourth wavelength band, and the difference between the working wavelength band of the optical system 30 and the fourth wavelength band is the Raman characteristic shift.

[0097] In this embodiment, after the light emitted by the light source 10 irradiates the human body part 40 to be tested, the reflected light from the human body part 40 includes a wavelength light signal generated by the Raman shift of biomolecules, which is the working wavelength band of the optical system 30 at this time.

[0098] Exemplarily, the fourth wavelength band is a specific wavelength within the range of 750-800 nm, for example, 785±5 nm. The operating wavelength band of the optical system 30 is a Raman shift wavelength within the range of 850-880 nm, for example, 861±10 nm.

[0099] In this embodiment, when a laser of a specific wavelength (e.g., 785 nm) is irradiated onto the human body part 40 to be tested, the photons are inelastically scattered by glucose molecules in the blood, generating a Raman shift spectrum related to the molecular vibration energy level, i.e., the Raman scattering effect. -1 There is a characteristic peak (C-O-C symmetric stretching vibration) at the center of the Raman shift spectrum, and its signal intensity is proportional to the concentration. Therefore, by using the detector 20 to sense the Raman shift spectrum information, the blood glucose concentration (for example, the blood glucose concentration) can be determined.

[0100] In some embodiments, the light source 10 may be configured to emit light in a single polarization state, for example, by using a linearly polarized laser (the polarization direction may be vertical or horizontal) to illuminate the body part 40 to be tested, so that the direction of the incident light field is aligned with a specific vibration mode of the glucose molecule (such as the COC symmetric stretching vibration 1125 cm -1 ) to match the polarization direction of the target signal, thereby enhancing the target signal.

[0101] In other embodiments, Raman spectroscopy can be combined with the photoacoustic effect (e.g., PAPEORS technology), leveraging the correlation between the rotation angle of polarized light in tissue and glucose concentration. By detecting polarization rotation information in the photoacoustic signal and complementing it with Raman spectroscopy, a multi-dimensional calibration model can be constructed, enhancing universality.

[0102] In some embodiments, the detector 20 is configured as a photodiode.

[0103] In this embodiment, unlike the first embodiment described above, the optical system 30 only needs to diffract (i.e., split) the spectral information near the characteristic peak from the light signal (i.e., Raman spectrum) reflected from the human body part 40 to be tested. Therefore, the blood glucose concentration (e.g., the blood glucose concentration in the blood) can be analyzed and determined by directly detecting the strength of the electrical signal through a photodiode (PD).

[0104] In this embodiment, since the optical system 30 (i.e., the first optical element 301) irradiates light signals of different wavelengths and / or polarization states onto different positions of the detector 20, it is possible to consider using regional photodiodes to directly detect the strength of the electrical signal for analysis.

[0105] In this embodiment, because CMOS sensors are more difficult to image than photodiodes, and because CMOS sensors require higher accuracy and have more dimensions, detector 20 uses photodiodes to directly detect energy in different polarization states to obtain optical signals. This approach can simplify the structure of the non-invasive blood glucose meter and reduce its design and manufacturing costs.

[0106] In some embodiments, the focus of the light source 10 is dynamically adjustable.

[0107] In this embodiment, piezoelectric ceramics or mechanical adjustment are used to ensure that the focus of the light source 10 is located in the blood, so that the output light of the light source penetrates the epidermis and focuses on the subcutaneous blood vessels (dermis). At this time, the collected Raman spectrum is mainly composed of blood components, reducing interference from the epidermal stratum corneum, melanin, etc.

[0108] refer to Figure 3 As shown, a fourth embodiment of the present invention provides a non-invasive blood glucose meter. In this non-invasive blood glucose meter, the optical system 30 is further equipped with a second optical element 302, which can improve the polarization extinction ratio and imaging efficiency of the first optical element 301. In this embodiment, the same reference numerals represent the same components with similar functions and are not further described.

[0109] In some embodiments, the optical system 30 includes a second optical element 302 located on the light-entering side of the first optical element 301. In this embodiment, the reflected light from the human body part 40 to be measured first passes through the second optical element 302 and is then transmitted (e.g., transmitted) by the second optical element 302 to the first optical element 301.

[0110] In some embodiments, the second optical element 302 is configured to modulate the incident light to reduce the incident angle of at least part of the incident light incident on the first optical element 301 .

[0111] In this embodiment, the second optical element 302 is configured to polarize or converge at least a portion of the incident light (e.g., light incident at the edge of the second optical element 302, or light incident at an angle greater than 30°), thereby reducing the angle of incidence of this portion of the incident light on the first optical element 301. This prevents the first optical element 301 from becoming sensitive to light incident at a large angle, improves the polarization extinction ratio and imaging efficiency of the first optical element 301, increases the field of view (e.g., to 75° or greater), and reduces the overall length of the system (e.g., to within 7 mm).

[0112] For example, Figure 3 The incident light at the edge of the second optical element 302 (i.e., incident at a large angle) is modulated (e.g., deflected) and converges toward the center, thereby reducing the incident angle of this portion of the incident light on the first optical element 301. The incident light at the center of the second optical element 302 (i.e., incident at a small angle) is modulated (e.g., deflected) and diverges toward the edge. However, the incident angle of this portion of the incident light on the first optical element 301 is still a small angle, and does not affect the polarization extinction ratio and imaging efficiency of the first optical element 301.

[0113] In some embodiments, the second optical element 302 is configured as a metasurface.

[0114] In this embodiment, the second optical element 302 is configured as a metasurface (e.g., a metalens), and the layout of the optical system 30 is more compact, which can further reduce the volume of the optical system 30 and achieve further miniaturization of the non-invasive blood glucose meter.

[0115] For example, since the second optical element 302 does not need to implement the modulation function of polarization separation, the nanostructure of the second optical element 302 can be a polarization-independent structure. However, the first optical element 301 needs to implement the modulation function of polarization separation, so the nanostructure of the first optical element 301 can be a polarization-dependent structure.

[0116] In some embodiments, the second optical element 302 is configured as a traditional lens.

[0117] In this embodiment, the second optical element 302 is configured as a traditional lens or a traditional lens group, such as a wide-angle lens or a fisheye lens.

[0118] In some embodiments, the first optical element 301 and the second optical element 302 are provided separately. In this embodiment, the first optical element 301 and the second optical element 302 are arranged in sequence along the transmission direction of the light path.

[0119] In other embodiments, the first optical element 301 and the second optical element 302 are integrally formed, and the layout of the optical system 30 is more compact, thereby reducing the volume of the optical system 30 .

[0120] Exemplarily, when both the first optical element 301 and the second optical element 302 are metasurfaces, the nanostructures of the first optical element 301 and the nanostructures of the second optical element 302 share a common substrate. When the second optical element 302 is a traditional lens, the first optical element 301 is formed on the second optical element 302 through semiconductor processing.

[0121] In some embodiments, the optical system 30 further includes a first optical component 303 located on the light-emitting side of the first optical element 301. In this embodiment, the first optical element 301 and the first optical component 303 are sequentially arranged along the optical transmission direction. After the light emitted from the first optical element 301 is irradiated by the first optical component 303, it is emitted to the detector 20 through the first optical component 303.

[0122] In some embodiments, the first optical component 303 is configured to converge the light emitted from the first optical element 301 .

[0123] In this embodiment, the first optical component 303 can achieve multi-point focusing, so that the output light of the optical system 30 converges at different positions of the detector 20. As a result, multiple (e.g., four) polarization images fully occupy the target surface of the detector 20, and the obtained sub-images of different polarization states have at least 100,000 pixels and clear resolution, which can meet the requirements of later use of neural network training data sets to identify and analyze image polarization, intensity and other information.

[0124] Illustratively, the first optical component 303 includes a first convex lens, a first concave lens, a second convex lens, and a second concave lens arranged in sequence along the light transmission direction.

[0125] In other embodiments, the first optical component 303 may also be composed of a metasurface, which can reduce the volume of the optical system 30.

[0126] In some embodiments, the optical system 30 further includes a fourth optical element 304 located on the light incident side of the detector 20 .

[0127] In this embodiment, the light signal reflected by the part of the human body to be tested will be filtered by the fourth optical element 304 (for example, filtering for wavelength or filtering for polarization state) when passing through the optical system 30, which can reduce the interference of stray light in the environment on the detector 20 sensing the light signal of specific wavelength and / or specific polarization state.

[0128] In some embodiments, the fourth optical element 304 is configured as a filter element.

[0129] In this embodiment, Figure 3 The fourth optical element 304 is located on the light incident side of the first optical element 301, and performs wavelength filtering on the stray light incident on the first optical element 301 (for example, incident from the second optical element 302), so as to prevent the first optical element 301 and the detector 20 from being interfered with by other wavelengths of light in the stray light.

[0130] refer to Figure 4 As shown, a fifth embodiment of the present invention provides a non-invasive blood glucose meter. In this non-invasive blood glucose meter, the fourth optical element 304 of the optical system 30 is configured as a polarization element, which can prevent the detector 20 from being interfered with by light of other polarization states within the stray light. In this embodiment, the same reference numerals represent the same components with similar functions and are not further described.

[0131] In this embodiment, the optical system 30 includes a first optical element 301. The first optical element 301 is configured as a monolithic multi-focal vector metalens, and the nanostructure of the first optical element 301 adopts a polarization-independent structure. Therefore, the first optical element 301 can achieve wavelength separation of the light signal reflected by the human body part 40 to be measured, thereby providing specific spectral information (such as Raman spectral information) for detection by the detector 20.

[0132] In this embodiment, the optical system 30 includes a fourth optical element 304 . The fourth optical element 304 is disposed on the sensing surface of the detector 20 .

[0133] In some embodiments, the fourth optical element 304 is configured as a polarization element.

[0134] In this embodiment, the polarization element is a polarizer (such as a polarizer), which can convert the polarization state of the light signal reflected by the human body part 40 to be tested, thereby providing specific polarization information for the detector 20 to sense, and can also prevent the detector 20 from being interfered with by other polarization states of light in the stray light.

[0135] For example, Figure 5 The polarization element (ie, the fourth optical element 304 ) is configured as a polarizer array, so as to perform polarization conversion on the light emitted from the first optical element 301 to different positions of the detector 20 .

[0136] refer to Figure 6 As shown, a sixth embodiment of the present invention provides a non-invasive blood glucose meter. In this non-invasive blood glucose meter, the fourth optical element 304 of the optical system 30 is configured as a filter element, which can prevent the detector 20 from being interfered with by light of other wavelengths within the stray light. In this embodiment, the same reference numerals represent the same components with similar functions and are not further described.

[0137] In this embodiment, the optical system 30 includes a first optical element 301. The first optical element 301 is configured as a monolithic multi-focal vector metalens, and the nanostructure of the first optical element 301 adopts a polarization-dependent structure. Therefore, the first optical element 301 can achieve polarization state separation of the light signal reflected by the human body part 40 to be measured, thereby providing specific polarization state information for detection by the detector 20.

[0138] In this embodiment, the optical system 30 includes a fourth optical element 304 . The fourth optical element 304 is disposed on the sensing surface of the detector 20 .

[0139] In some embodiments, the fourth optical element 304 is configured as a filter element.

[0140] In this embodiment, the fourth optical element 304 can perform wavelength separation on the light signal reflected by the human body part 40 to be tested, thereby providing specific spectral information (such as Raman spectral information) for the detector 20 to sense, and can also prevent the detector 20 from being interfered with by other wavelengths of light in the stray light.

[0141] Exemplarily, the filter element (ie, the fourth optical element 304 ) is configured as a filter array, so as to perform wavelength separation on the light emitted from the first optical element 301 to different positions of the detector 20 .

[0142] In some embodiments, the optical system 30 includes a micro lens array (e.g., Figure 7 As shown), the microlenses in the microlens array correspond one-to-one to the filters in the filter array, thereby converging the incident light incident on each filter, which is beneficial for the filter array to filter the wavelength.

[0143] According to another aspect of the present invention, a design method for a non-invasive blood glucose meter is provided. The structure and function of the non-invasive blood glucose meter are as described above and will not be repeated here.

[0144] Specifically, the design method of the non-invasive blood glucose meter includes the following steps:

[0145] The operating wavelength band of the optical system 30 is determined according to the wavelength band of the light emitted by the light source 10 .

[0146] In some embodiments, the light source 10 is configured as a narrow-band light source.

[0147] In this embodiment, the wavelength band of the light emitted by the light source 10 is around 940 nm. At this time, the operating wavelength band of the optical system 30 is the same as the wavelength band of the light emitted by the light source 10, that is, around 940 nm.

[0148] In this embodiment, the wavelength band of the light emitted by the light source 10 is near the fourth wavelength band (for example, 750-800 nm). At this time, the difference between the working wavelength band of the optical system 30 and the fourth wavelength band is the Raman characteristic shift, that is, the working wavelength band of the optical system 30 is the Raman shift wavelength in the range of 850-880 nm.

[0149] In this embodiment, the light emitted by the light source 10 is configured to be in a single polarization state, and the polarization direction of the light emitted by the light source 10 is dynamically adjustable.

[0150] In other embodiments, the light source 10 is configured as a broadband light source.

[0151] In this embodiment, the light emitted by the light source 10 includes at least a first wavelength band and a second wavelength band. The light emitted by the light source 10 may include a first wavelength band, a second wavelength band, and a third wavelength band. In this case, the operating wavelength band of the optical system 30 corresponds one-to-one to the wavelength band of the light emitted by the light source 10.

[0152] Based on the working wavelength band of the optical system 30 , the first optical element 301 is designed accordingly to direct the output light of the optical system 20 to different positions of the detector 20 .

[0153] In this embodiment, the phase (ie, phase distribution) of the first optical element 301 is determined according to the modulation function (eg, diffraction beam splitting function) of the first optical element 301 .

[0154] Exemplarily, the first optical element 301 has a first phase and a second phase superimposed on each other.

[0155] In this embodiment, while maintaining the phase, the metasurface, when performing phase arrangement, selects different metastructure unit periods, nanostructure feature sizes, and nanostructure heights to achieve higher efficiency for incident light in operating wavelength bands (e.g., the first wavelength band, the second wavelength band, and the third wavelength band). This selection process can also result in lower efficiency for incident light in other wavelength bands (e.g., non-operating wavelength bands), thereby filtering out optical signals in other wavelength bands (e.g., non-operating wavelength bands) and performing a light filtering function.

[0156] The optical signal that the detector 20 needs to sense is determined according to the output light of the optical system 30 .

[0157] In this embodiment, the optical signal reflected from the human body part 40 to be measured is modulated by the optical system 30, and then emitted as an optical signal of a specific wavelength (i.e., spectral information) and a specific polarization state (i.e., polarization information) to the detector 20. In this case, the optical signal that the detector 20 needs to sense is the optical signal of the specific wavelength (i.e., spectral information) and specific polarization state (i.e., polarization information) emitted by the optical system 30.

[0158] The optical system 30 is designed accordingly according to the parameters of the detector 20 so that the detector 20 can sense polarization images formed at different positions.

[0159] In this embodiment, Figure 1 The detector 20 is configured as a CMOS sensor, and the optical system 30 needs to image the light signal reflected by the human body part 40 to be tested, that is, to form polarization images at different positions of the detector 20.

[0160] In this embodiment, for Figure 3 For the fourth embodiment of the non-invasive blood glucose meter shown, in order to ensure that the polarization images formed at different positions can be sensed by the detector 20, multiple parameters of the optical system 30 need to be designed.

[0161] The first parameter of the optical system 30 satisfies:

[0162] f*tan(θ grating )>0.5,IMGH>3.4mm;(1)

[0163] Wherein, f is the effective focal length of the optical system 30 for imaging, θ grating is the diffraction angle of the central field light of the optical system 30 (ie, 0° incidence) after passing through the first optical element 301, and IMGH is the target surface size of the detector 20.

[0164] In this embodiment, the center of the polarization image is shifted to a relatively optimal position by the coordinated design of the first optical element 301 and the focal length of the optical system 30, ensuring that the four polarization images do not overlap and that the occupied area is maximized. The diagonal size of the IMGH target surface is greater than 3.4 mm to ensure that the optical system 30 has a sufficiently large image surface and pixel count, so that the polarization image pixels reach at least 10w or more. Among them, the four polarization images are as follows: Figure 8 shown.

[0165] The second parameter of the optical system 30 satisfies:

[0166] 30 <f1 / f2<90; (2)

[0167] The first optical element 301 and the second optical element are combined to form a second optical assembly, f1 is the combined focal length of the second optical assembly, and f2 is the combined focal length of the first optical assembly 303 .

[0168] In this embodiment, by constraining the ratio of f1 to f2, the optical system 30 can be imaged at a specified target surface position of the detector 20 after passing through two optical components at a specific large incident angle, and the area of ​​the polarization image (e.g., circular) is maximized without interfering with each other and without exceeding the range of the detector 20.

[0169] The third parameter of the optical system 30 satisfies:

[0170] 0.04mm <d<0.8mm; (3)

[0171] Wherein, d is the distance from the second optical component to the aperture stop of the optical system 30 .

[0172] In this embodiment, by controlling the distance d, parameters such as the "assembly process" between the second optical component and the first optical component 303, the "total optical length of the system", and the "vignetting size of each field of view light beam passing through the aperture stop after being emitted through the first optical element 301" can be adjusted.

[0173] In this embodiment, if d is approximately 0.04 mm, the second optical component and the first optical component 303 are assembled and supported in the same barrel structure to minimize the total optical length, facilitating module miniaturization. Furthermore, vignetting after the first optical element 301 passes through the aperture stop is relatively minimal, resulting in less light energy transmission loss.

[0174] In this embodiment, if d is around 0.8 mm, the second optical assembly and first optical assembly 303 are often assembled separately using two lens barrels and then glued together, resulting in a longer overall optical length. Furthermore, the external field beam will experience increased vignetting after exiting through the first optical element 301. This increased vignetting can be mitigated by reducing the aperture of the first optical element 301, thus avoiding the risk of uneven brightness in the upper and lower regions of the polarized image.

[0175] The fourth parameter of the optical system 30 satisfies:

[0176] 30<|Δφ / R M |<450; (4)

[0177] Wherein, Δφ is the maximum phase difference provided by the second optical element 302 at a single wavelength, R M is the optical effective radius of the second optical element 302.

[0178] In this embodiment, at a single wavelength, different positions of the second optical element 302 generally provide different phases. By constraining the relationship between the maximum phase difference of the second optical element 302 and the optically effective radius of the second optical element 302, the second optical element 302 achieves a better phase matching effect, further fully utilizing the optical performance of the second optical element 302.

[0179] The fifth parameter of the optical system 30 satisfies:

[0180] FOV image >3·θ grating ; (5)

[0181] Among them, FOV image is the viewing angle range of the first optical component 303 under the selected target surface of the detector 20, θ grating is the diffraction angle of the central field light of the optical system 30 (ie, 0° incidence) after passing through the first optical element 301.

[0182] In this embodiment, by constraining the parameter (5), the imaging of the four polarization images on the target surface of the detector 20 is shifted to a suitable position, while ensuring that the field of view of the first optical component 303 can cover the maximum angle of the first optical element 301.

[0183] In this embodiment, even if the diffraction angle of the first optical element 301 is too small, the polarization image will not be formed at the edge of the detector 20, thus avoiding the polarization image area being too small and the number of pixels being insufficient. Even if the diffraction angle of the first optical element 301 is too large, the polarization image will not overflow the edge of the detector 20.

[0184] The optical system 30 is designed accordingly according to the parameters of the detector 20 so that the detector 20 can sense spectral information and polarization information at different positions.

[0185] In this embodiment, Figure 2 Detector 20 is configured as a photodiode. The optical system 30 only needs to diffract (i.e., split) the spectral information near the characteristic peak from the light signal (i.e., Raman spectrum) reflected from the human body part 40 to be tested. Thus, the blood glucose concentration (e.g., the blood glucose concentration) can be analyzed and determined by directly detecting the strength of the electrical signal through the photodiode.

[0186] In some embodiments, Figure 4 As for the fifth embodiment of the non-invasive blood glucose meter shown, in order to ensure that the polarization images formed at different positions can be sensed by the detector 20, the optical system 30 needs to be structurally designed.

[0187] In this embodiment, the first optical element 301 is configured as a monolithic multi-focal vector meta-lens, and the nanostructure of the first optical element 301 adopts a polarization-independent structure, so that the first optical element 301 can achieve wavelength separation of the light signal reflected by the human body part 40 to be tested, thereby providing specific spectral information (such as Raman spectral information) for sensing by the detector 20.

[0188] In this embodiment, the fourth optical element 304 is configured as a polarization element, which is a polarizer (such as a polarizer), which can convert the polarization state of the light signal reflected by the human body part 40 to be tested, thereby providing specific polarization information for the detector 20 to sense, and can also prevent the detector 20 from being interfered with by other polarization states of light in the stray light.

[0189] In other embodiments, Figure 6 As for the sixth embodiment of the non-invasive blood glucose meter shown, in order to ensure that the polarization images formed at different positions can be sensed by the detector 20, the optical system 30 needs to be structurally designed.

[0190] In this embodiment, the optical system 30 includes a first optical element 301. The first optical element 301 is configured as a monolithic multi-focal vector metalens, and the nanostructure of the first optical element 301 adopts a polarization-dependent structure. Therefore, the first optical element 301 can achieve polarization state separation of the light signal reflected by the human body part 40 to be measured, thereby providing specific polarization state information for detection by the detector 20.

[0191] In this embodiment, the fourth optical element 304 is configured as a filter element, which can separate the wavelengths of the light signal reflected by the human body part 40 to be tested, thereby providing specific spectral information (such as Raman spectral information) for sensing by the detector 20, and can also prevent the detector 20 from being interfered with by other wavelengths of light in the stray light.

[0192] For example, Figure 9 Figure a shows a real shot of a non-invasive blood glucose meter. After at least part of the optical system 30 is made of a metasurface, the volume of the optical system 30 is small. Figure 9 b, a polarization image of the light signal reflected from the human body part 40 (ie, the palm) after being sensed by the detector 20.

[0193] For example, after the polarized image is cut, registered, and distortion corrected, the polarized anti-reflection function is tested, such as Figure 10 As shown, it can be seen that the optical system 30 has a high extinction ratio (measured extinction ratio greater than 20 dB at all viewing angles) in a small volume and can completely eliminate reflections.

[0194] For example, Figure 11a, polarization image sensed by detector 20 when light source 10 has only the third wavelength band (e.g. 900 nm). Figure 11 b, polarization images sensed by the detector 20 when the light source 10 has a first wavelength (e.g., 940 nm), a second wavelength (e.g., 860 nm), and a third wavelength (e.g., 900 nm). Through the spectrum reconstruction algorithm, discrete spectral information can be obtained, such as Figure 12 a is the polarization image corresponding to the second band, such as Figure 12 b is the polarization image corresponding to the third band, such as Figure 12 c is the polarization image corresponding to the first band, such as Figure 12 d is the polarization image after spectral fusion.

[0195] For example, Figure 13 Spectral information and polarization information sensed by the detector 20 are shown. After acquiring the spectral information and polarization information, the concentration information of glucose and protein can be obtained by the following method.

[0196] The Stokes parameters (S0, S1, S2, and S3) are four parameters that describe the polarization state of light: S0 is the total light intensity (related to the total energy of the light); S1 is the intensity difference between the horizontal (0°) and vertical (90°) linear polarization components; S2 is the intensity difference between the 45° and 135° linear polarization components; S3 is the intensity difference between the right-handed and left-handed circular polarization components; the degree of polarization (DOP) is the ratio of the polarized light intensity to the total light intensity, reflecting the degree of polarization of the light; and the angle of polarization (AoP) is the angle between the vibration direction of linearly polarized light and the reference axis.

[0197] Glucose has optical rotation (chiral molecular properties). When polarized light (such as linearly polarized light) passes through a medium containing glucose, the polarization plane will rotate (the optical rotation angle α∝C Glucose ·L, where C is the concentration and L is the optical path length). Changes in AoP directly reflect changes in optical rotation angle and can be used to calculate glucose concentration.

[0198] Proteins (such as albumin) can affect the polarization state through birefringence and scattering properties. Birefringence effect: The anisotropy of protein molecular arrangement or medium structure causes the incident light to decompose into two orthogonal polarized beams, resulting in phase delay (Δφ∝C Protein Scattering properties: Changes in protein concentration may alter the scattering properties of the medium, affecting the degree of polarization depolarization (DOP reduction).

[0199] Concentration inversion of glucose concentration:

[0200] Rotation of the Angle of Polarization (AoP): The optical rotation of glucose causes the polarization direction of linearly polarized light to rotate. The AoP shift α is related to the glucose concentration C Glucose Proportional to:

[0201] α=R(λ,T)·C·L

[0202] Where R is the optical rotation of glucose (related to wavelength λ and temperature T).

[0203] The first embodiment of the non-invasive blood glucose meter is used to detect blood glucose: the AoP of the incident light and the outgoing light are compared, and the concentration is calculated based on the calibration curve or physical model.

[0204] Relationship of Stokes parameters: The change of optical rotation angle will directly affect the ratio of S1 and S2. For example, after the original polarization angle of light is 0°, its polarization state can be expressed as:

[0205] S′1=S0cos(2Δθ), S′2=S0sin(2Δθ)

[0206] Blood glucose testing is performed using the second embodiment of a non-invasive blood glucose meter: the birefringence coefficient of protein is wavelength-dependent, and its contribution is separated using multi-wavelength data.

[0207] Depolarization due to scattering: Increased protein concentration may enhance scattering, leading to a decrease in DOP:

[0208]

[0209] The inverse analysis was performed by establishing an empirical relationship between DOP and protein concentration.

[0210] Blood glucose testing is performed using a combination of the first and second embodiments of a non-invasive blood glucose meter: Glucose and protein have different optical rotations and birefringence coefficients at different wavelengths. For example, glucose has a strong optical rotation at 940nm, while protein has more pronounced birefringence in the near-infrared band (e.g., 860nm). By measuring the multi-wavelength Stokes parameters (S1, S2), a linear equation system is constructed to decouple the contributions of these two parameters:

[0211]

[0212] Solving the equations yields C Glucose and C Protein .

[0213] Machine learning model: Use a large amount of experimental data to train the model (such as support vector machine, neural network), input multi-wavelength Stokes parameters, DOP and AoP, and output concentration value. Through calculation and actual blood test results, we can obtain Figure 14 The results, where Figure 14 a is the glucose concentration, Figure 14 b is the protein concentration.

[0214] The third embodiment of the non-invasive blood glucose meter measures blood glucose concentration based on the following principles:

[0215] The principle of polarized Raman spectroscopy is the polarization-selective enhancement mechanism. The Raman signal intensity is related to the anisotropy of the molecular polarizability tensor. Polarization technology achieves selective excitation and interference suppression of the target molecular vibrational mode by controlling the polarization direction of the incident light (ei) and scattered light (es):

[0216] I Raman ∝|e i ·α·e s | 2

[0217] Where α is the molecular polarizability tensor. The COC symmetric stretching vibration of glucose (1125 cm -1 ) has a specific polarization direction, and its signal can be enhanced by matching the polarization direction.

[0218] The combination of the first and third embodiments of the non-invasive blood glucose meter can suppress background fluorescence through polarization filtering. Skin background fluorescence is mostly isotropically scattered, while the Raman signal is polarization-dependent. Fluorescence can be suppressed by using a polarizer (with a polarization direction orthogonal to the incident polarization):

[0219]

[0220] Here, ρ = I⊥ / I∥ is the depolarization rate, ρ of the symmetric vibrational mode of glucose is < 0.75, and ρ of the fluorescence background is ≈ 0.75.

[0221] It should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0222] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A non-invasive blood glucose meter, characterized in that: include: light source; detector; An optical system, wherein the light emitted by the light source is reflected by the part of the human body to be measured and then emitted toward the optical system, the optical system is located on the light incident side of the detector, and the detector is used to sense the light emitted by the optical system; The optical system includes a first optical element, which is configured to diffract incident light so that outgoing light of the optical system is irradiated at different positions of the detector, and the first optical element is configured as a metasurface.

2. The non-invasive blood glucose meter according to claim 1, wherein: The first optical element is configured to diffract incident light, specifically comprising: The first optical element is configured to perform wavelength separation and / or polarization state separation on the incident light.

3. The non-invasive blood glucose meter according to claim 1, wherein: The first optical element has a first phase and a second phase, wherein the first phase is configured to diffract incident light, and the second phase is configured to modulate the incident light so that the outgoing light of the optical system converges at different positions of the detector.

4. The non-invasive blood glucose meter according to claim 1, wherein: The optical system includes a second optical element located on a light incident side of the first optical element, wherein the second optical element is configured to modulate incident light to reduce an incident angle of at least a portion of the incident light incident on the first optical element.

5. The non-invasive blood glucose meter according to claim 4, characterized in that: The second optical element is configured as a metasurface or a traditional lens, and the first optical element and the second optical element are arranged separately.

6. The non-invasive blood glucose meter according to claim 1, wherein: The optical system further includes a first optical component located on a light-emitting side of the first optical element, wherein the first optical component is configured to converge the light emitted from the first optical element.

7. The non-invasive blood glucose meter according to claim 1, wherein: The optical system further includes a fourth optical element located on the light incident side of the detector, and the fourth optical element is configured as a filter element or a polarization element.

8. The non-invasive blood glucose meter according to claim 1, wherein: The light emitted by the light source is configured to be in a single polarization state, and the polarization direction of the light emitted by the light source is dynamically adjustable.

9. The non-invasive blood glucose meter according to claim 1, wherein: The output light of the light source includes at least a first wavelength band and a second wavelength band, and the first wavelength band and the second wavelength band are both configured as working wavelength bands of the optical system.

10. The non-invasive blood glucose meter according to claim 1, wherein: The output light of the light source includes a fourth wavelength band, and the difference between the working wavelength band of the optical system and the fourth wavelength band is the Raman characteristic shift.

11. The non-invasive blood glucose meter according to any one of claims 8 to 10, characterized in that: The detector is configured as a CMOS sensor or a photodiode.

12. A method for designing a non-invasive blood glucose meter according to any one of claims 1 to 11, characterized in that: The steps include: Determine the working band of the optical system according to the wavelength of the light emitted by the light source; Based on the working band of the optical system, the first optical element is designed accordingly to irradiate the output light of the optical system at different positions of the detector; The optical signal that the detector needs to sense is determined based on the output light of the optical system.

13. The design method of the non-invasive blood glucose meter according to claim 12, wherein: According to the parameters of the detector, the optical system is designed accordingly so that the detector can sense the polarization images formed at different positions.

14. The design method of the non-invasive blood glucose meter according to claim 12, wherein: According to the parameters of the detector, the optical system is designed accordingly so that the detector can sense spectral information and polarization information at different positions.

Images