Photoacoustic cell, detection system and method for photoacoustic spectrum noninvasive blood glucose detection

Abstract

The invention discloses a photoacoustic cell, a detection system and a method for photoacoustic spectrum noninvasive blood glucose detection, the photoacoustic cell adopts any three-dimensional structure of crossed cylindrical cavities, one ends of the two cylindrical cavities are respectively provided with a laser diode and a microphone for laser incidence hole and sound reception, and the intersection surface of the other ends of the two cylindrical cavities is a hole for placing an object to be detected; the internal crossed cylindrical cavities are of a symmetrical structure, a certain included angle is kept between the two cylindrical cavities, the radiuses of the cylindrical cavities can be randomly changed along with the size of a light source, and the cylindrical cavities with different radiuses correspond to different characteristic frequencies; the appearance of the photoacoustic cell can be any three-dimensional structures such as a triangular prism, a cuboid and a ladder column; the material of the photoacoustic cell can be polished aluminum, stainless steel, brass and other metals with high thermal diffusivity. The photoacoustic cell can be used for small integrated photoacoustic spectrum noninvasive blood glucose detection, and not only can be used for detecting the concentration of blood glucose, but also can be used for detecting the concentrations of other various solutions.

Description

Technical Field

[0001] The invention belongs to the technical field of photoacoustic spectroscopy and blood sugar detection, and particularly relates to a photoacoustic cell, a detection device and a method for non-invasive blood sugar detection using photoacoustic spectroscopy. Background Art

[0002] With the changes in people's lifestyles and eating habits, the number of diabetic patients has increased year by year, and the workload of blood glucose testing has also increased accordingly. The current mainstream invasive blood glucose testing technology is cumbersome to operate and has high testing costs, and even has the risk of infection. Therefore, non-invasive blood glucose testing technology has gradually emerged.

[0003] Photoacoustic spectroscopy uses the microscopic local thermal expansion generated when laser irradiates the skin to modulate the ultrasonic signal, and calculates the glucose concentration by tracking the peak change of this ultrasonic signal. Photoacoustic spectroscopy has high sensitivity and a wide range of laser wavelength selection, making it an excellent method for non-invasive blood glucose detection.

[0004] In the prior art, the volume of the photoacoustic cell in the blood glucose detection system using photoacoustic spectroscopy is generally too large, and it is difficult to integrate it with the laser and microphone in a small space. Summary of the invention

[0005] In order to solve the shortcomings of the prior art and achieve the purpose of small-scale integration of a photoacoustic cell with a simple structure and good enhancement effect on acoustic wave signals, the present invention adopts the following technical solutions:

[0006] A photoacoustic cell for photoacoustic spectrum detection is provided with a penetrating cavity, at least two symmetrical cavities intersecting at one surface of the photoacoustic cell, the intersecting surface of the cavities is used for photoacoustic spectrum detection, and the other end surfaces of the two cavities are respectively used for laser incidence and sound collection.

[0007] Furthermore, the photoacoustic cell is a triangular prism, and the cylindrical cavities of the two prism faces intersect at the third cylindrical face, which is used for photoacoustic spectrum detection. The cross-cylindrical cavity structure perfectly matches the straight triangular prism, maximizing the volume of the triangular prism. In addition to the cavity, only part of the excess shell is used to support and fix the laser diode and the microphone. The triangular prism shape is also more stable and easier to fix in the instrument.

[0008] Furthermore, the triangular prism is a right triangular prism, and symmetrical cylindrical cavities are vertically opened on two right-angled prism surfaces and intersect at an oblique prism surface.

[0009] Furthermore, the right angle side length of the straight triangular prism is l, the hypotenuse length is l√2, the diameter of the cylindrical cavity is 0.38l, and Figure 4 , Figure 5It can be seen that the resonance peak position at this time is exactly at the end surface of one side of the two cylindrical cavities. If a radio receiver is set at this position, the strongest sound signal can be received.

[0010] Furthermore, a cylindrical cavity is provided at the center of the right-angled prism surface, and intersects with the center of the oblique prism surface to form an elliptical shape.

[0011] Furthermore, the angle between the two cavities and the symmetry axis is within a range of 30° to 60°. If the angle is too small, the cross volume in the cavity will be too large, thereby weakening the acoustic wave resonance effect. If the angle is too large, the volume of the photoacoustic cell will increase.

[0012] Furthermore, the size of the cavity is coordinated with the size of the light source, and cavities of different sizes correspond to different characteristic frequencies. The size of the corresponding cavity is set according to the modulation frequency of the light source.

[0013] Furthermore, the photoacoustic cell is made of metal material with high thermal diffusivity, and the metal inner wall of the cavity is polished.

[0014] A detection system for non-invasive blood glucose detection using photoacoustic spectroscopy, the detection system comprises the photoacoustic cell for photoacoustic spectroscopy detection, the intersection surface of the photoacoustic cell is used as a hole for placing the object to be detected, and a laser emitting device and an ultrasonic receiving device are respectively arranged on the other end surfaces of the two cavities.

[0015] A detection method for non-invasive blood glucose detection using photoacoustic spectroscopy, comprising: constructing a photoacoustic cell for photoacoustic spectroscopy detection, placing an object to be detected on the intersecting surface of the acoustic cell, inputting a laser through the other end surface of a cavity, and acquiring an ultrasonic signal at the other end surface of another cavity.

[0016] The advantages and beneficial effects of the present invention are:

[0017] The photoacoustic cell of the present invention is very small in size and easy to integrate, providing a new idea for making a portable non-invasive blood glucose detector; wherein, the cross-type cylindrical cavity structure is simple in structure, and the intersection surface of the light source hole and the sound receiving hole can directly receive the sound wave signal from the sound source as a test hole, thereby reducing the attenuation of the sound wave; while being small in size and easy to integrate, it also has an excellent signal enhancement effect; the size of the cross-type cylindrical cavity of the photoacoustic cell can be arbitrarily changed with the light source, and it is highly adaptable; the shape of the photoacoustic cell is not subject to any restrictions, and it only needs to ensure that the internal cavity structure is a cross-type cylindrical structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 4 is a cross-sectional view of the cross-cylindrical cavity of the photoacoustic cell in an embodiment of the present invention.

[0019] Figure 2 Schematic diagram of the side structure of the photoacoustic cell in an embodiment of the present invention.

[0020] Figure 3 It is a perspective view of the three-dimensional structure of the photoacoustic cell in an embodiment of the present invention.

[0021] Figure 4 Graph showing the simulation results of the sound pressure level of the cross-cylindrical cavity of the photoacoustic cell in an embodiment of the present invention.

[0022] Figure 5 This is a diagram of the sound pressure level simulation results after the cross-cylindrical cavity of the photoacoustic cell is lengthened in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0024] like Figure 1 As shown, a small integrated photoacoustic cell for photoacoustic spectroscopy detection is shown. The shape of the photoacoustic cell is a right triangular prism with isosceles right triangles on the front and back sides. The hypotenuse L1 of the isosceles triangle is 10√2mm. Holes are punched from the corresponding faces of the two right-angled sides. The positions of the two holes are symmetrical to each other. The punching direction is perpendicular to the prism surface. The diameter d2 of the hole is 3.8mm. A laser diode and a microphone are placed at the two hole ports respectively. The diameter d1 of the laser diode is 3.6mm, which can just be inserted into the cavity.

[0025] The photoacoustic cell can also be a small triangular prism, a cuboid, a ladder column or any other three-dimensional structure; its material can be polished aluminum, stainless steel, brass or other metal materials with high thermal diffusivity;

[0026] The cross-cylindrical cavity structure inside the photoacoustic pool is symmetrical, and the shapes and sizes of the two cylindrical cavities are exactly the same; the size of the cross-cylindrical cavity can vary with the size of the light source, and cavities of different sizes correspond to different characteristic frequencies, and the modulation frequency of the light source also changes accordingly. For the triangular prism, two holes are punched from one face of the metal material to the other face, and the hole surface serves as the cross surface of the two cylindrical cavities, that is, the common surface; the positions of the two holes are symmetrical and the size is the same, and the common surface of the two holes is elliptical; the angle between the two holes and the symmetry axis should be between 30° and 60°. If the angle is too small, the cross volume in the cavity will be too much, which will weaken the acoustic wave resonance effect, and if the angle is too large, the volume of the photoacoustic pool will increase; the metal inner wall of the cross-cylindrical cavity is polished; the laser diode and the microphone are placed at the ports of the two cylindrical cavities respectively.

[0027] like Figure 2 As shown, the side length L2 of the photoacoustic cell is 10 mm, and the height H of the photoacoustic cell is 7.07 mm. From the side, it can be seen intuitively that the circular hole is located in the center of the side. The side structure is simple with only one circular hole for placing the laser diode and the microphone.

[0028] like Figure 3 As shown, the cross-cylindrical cavity structure fits perfectly with the straight triangular prism, maximizing the volume of the triangular prism. In addition to the cavity, only part of the excess shell is used to support and fix the laser diode and the microphone. The triangular prism shape is also more stable and easier to fix in the instrument.

[0029] like Figure 4 As shown in the figure, the pressure acoustic simulation results of the internal cavity structure of the photoacoustic pool show that at the characteristic frequency, a resonance valley appears in the middle of the two cylindrical cavities, indicating that the structure belongs to a resonant photoacoustic pool, and the end faces of the two circular holes are at the resonance peak, which can effectively enhance the sound pressure intensity. It can be concluded from the results that the photoacoustic pool designed by the present invention has a good effect of enhancing the sound pressure.

[0030] like Figure 5 As shown, this figure is used for Figure 4 To add an explanation, Figure 4 The cavity is relatively short, which cannot well explain that the two circular hole end faces are at the resonance peak. Increasing the length of the two cylindrical cavities will cause two resonance valleys to appear in the cavity. Figure 4 The position of the end face of the circular hole in Figure 5 The center position between the two resonance valleys corresponds to the resonance peak position. Placing a microphone at this position can receive the strongest sound signal.

[0031] A detection system for non-invasive blood glucose detection using photoacoustic spectroscopy includes a photoacoustic cell for photoacoustic spectroscopy detection, the intersection surface of the photoacoustic cell is used as a hole for placing the object to be tested, and a laser emitting device and an ultrasonic receiving device are respectively arranged on the other end surfaces of two cavities.

[0032] A detection method for non-invasive blood glucose detection using photoacoustic spectroscopy is disclosed. A photoacoustic cell for photoacoustic spectroscopy detection is constructed, the intersection surface of the acoustic cell is used to place an object to be detected, a laser is input through the other end surface of a cavity, and an ultrasonic signal is obtained at the other end surface of another cavity.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photoacoustic cell for photoacoustic spectroscopy detection, provided with a through cavity, characterized in that: At least two symmetrical cavities intersect at one surface of the photoacoustic cell, the intersecting surface of the cavities is used for photoacoustic spectrum detection, and the other end surfaces of the two cavities are used for laser incidence and sound collection respectively.

2. The photoacoustic cell for photoacoustic spectroscopy detection according to claim 1, characterized in that: The photoacoustic cell is a triangular prism, and the cylindrical cavities of two prism surfaces intersect at the third cylindrical surface, which is used for photoacoustic spectrum detection.

3. The photoacoustic cell for photoacoustic spectroscopy detection according to claim 2, characterized in that: The triangular prism is a right triangular prism, and symmetrical cylindrical cavities are vertically opened on two right-angled prism surfaces and intersect at an oblique prism surface.

4. The photoacoustic cell for photoacoustic spectroscopy detection according to claim 3, characterized in that: The right angle side length of the right triangular prism is l, the hypotenuse length is l√2, and the diameter of the cylindrical cavity is 0.38l.

5. The photoacoustic cell for photoacoustic spectroscopy detection according to claim 3, characterized in that: A cylindrical cavity is provided at the center of the right-angled prism surface, and intersects at the center of the oblique prism surface to form an ellipse.

6. The photoacoustic cell for photoacoustic spectroscopy detection according to claim 1, characterized in that: The included angle between the two cavities and the symmetry axis is within a range of 30° to 60°.

7. The photoacoustic cell for photoacoustic spectroscopy detection according to claim 1, characterized in that: The cavity size is set in coordination with the light source size. Cavities of different sizes correspond to different characteristic frequencies. The size of the corresponding cavity is set according to the modulation frequency of the light source.

8. The photoacoustic cell for photoacoustic spectroscopy detection according to claim 1, characterized in that: The photoacoustic cell is made of a metal material with high thermal diffusivity.

9. A detection system for non-invasive blood glucose detection using photoacoustic spectroscopy, characterized in that: The detection system comprises the photoacoustic cell for photoacoustic spectroscopy detection as claimed in claim 1, the intersection surface of the photoacoustic cell is used as the hole for placing the object to be tested, and a laser emitting device and an ultrasonic receiving device are respectively arranged on the other end surfaces of the two cavities.

10. A detection method for non-invasive blood glucose detection using photoacoustic spectroscopy, characterized in that: Construct the photoacoustic cell for photoacoustic spectroscopy detection as described in claim 1, use the intersecting surface of the acoustic cell to place the object to be tested, input laser through the other end surface of one cavity, and obtain ultrasonic signals at the other end surface of the other cavity.

Images