Optical device and method for measuring skin elasticity and moisture content

Abstract

This invention provides an optical device and method for measuring skin elasticity and moisture content. The device includes a reference module, a control module, and an excitation module, a detection module, and a receiving module electrically connected to the control module. Under the control of the control module, the excitation module emits ultrasonic excitation that acts on the skin tissue of the human subject, causing the skin tissue to vibrate and generate shear waves. Simultaneously, under the control of the control module, the detection module emits a detection beam, which, after passing through an ultrasonic transducer, acts on the skin tissue of the subject and reflects a feedback beam. The detection beam is used to detect the shear waves. Under the control of the control module, the receiving module detects the feedback beam and the reference beam. Finally, by measuring the shear waves, a non-contact, quantitative, and accurate measurement of skin elasticity and moisture content is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of skin elasticity and moisture content measurement, specifically relating to an optical device and method for measuring skin elasticity and moisture content. Background Technology

[0002] As living standards continue to improve, people are paying more and more attention to their physical health.

[0003] Among these, skin hydration and elasticity are important indicators for assessing skin health and aging. Studies show that ideal skin should be smooth, moist, and elastic. When the stratum corneum's hydration level falls below 10%, the skin becomes dry and flaky, loses elasticity, and its barrier function is compromised. Research indicates that most skin diseases and signs of skin aging involve varying degrees of skin barrier dysfunction. Therefore, measuring skin hydration and elasticity is crucial.

[0004] Currently, various technologies are used to test the elasticity and hydration content of human skin tissue. However, most devices rely on contact with the skin, using negative pressure to lift and release the skin, and then estimating the skin's elasticity and hydration based on its rebound. This type of testing method has several drawbacks. Firstly, the testing device needs to be in contact with the skin, which can damage the test subject's skin and potentially lead to cross-infection. Secondly, the skin's rebound process is affected by various external environmental factors, making it impossible to accurately quantify skin elasticity and hydration. Summary of the Invention

[0005] Based on this, the present invention provides an optical device and method for measuring skin elasticity and moisture content, aiming to solve the problem that in the prior art, traditional methods for measuring skin elasticity and moisture content require contact with the skin of the test subject and cannot accurately quantify the data.

[0006] A first aspect of the present invention provides an optical device for measuring skin elasticity and moisture content, the device comprising:

[0007] The excitation module includes a function signal generator, a power amplifier, and an ultrasonic transducer connected in sequence. The ultrasonic transducer is used to emit ultrasonic excitation under the action of the function signal generator and the power amplifier, which acts on the skin tissue of the human tester, causing the skin tissue to vibrate and generate shear waves.

[0008] The detection module includes a swept-frequency laser, a first three-pole polarization controller, a first beam splitter, a first optical circulator, a second three-pole polarization controller, a collimating lens, a scanning galvanometer, and a convex lens, which are connected in sequence via optical paths. The convex lens is connected to the optical path of the ultrasonic transducer. The detection beam emitted from the convex lens passes through the ultrasonic transducer, acts on the skin tissue of the subject, and reflects a feedback beam. The detection beam is used to detect the shear wave.

[0009] The reference module includes a second optical circulator connected to the first beam splitter optical path, and a third three-paddle polarization controller, a variable aperture, a plano-convex mirror, and a dielectric film reflector connected sequentially to the second optical circulator optical path.

[0010] The receiving module includes a second beam splitter connected to the optical paths of the first optical circulator and the second optical circulator respectively, and a balanced detector connected to the optical path of the second beam splitter. The balanced detector is used to detect the feedback beam emitted by the first optical circulator and the reference beam emitted by the second optical circulator.

[0011] The control module is used to be electrically connected to the swept laser, the balanced detector and the function signal generator respectively.

[0012] Furthermore, the center wavelength of the scanning laser is 1310 nm, and the bandwidth is 100 nm.

[0013] Furthermore, the ultrasonic transducer includes a housing, a pad, a backing, an electrode, a piezoelectric crystal, an acoustic matching layer, a protective layer, and a lens, which are stacked sequentially within the housing. The electrode extends outward with electrode wires. The piezoelectric crystal is made of transparent epoxy resin and is convex in shape. A coil is disposed on the outside of the piezoelectric crystal.

[0014] Furthermore, the first beam splitter is a 90:10 beam splitter, wherein the first beam splitter is used to control 90% of the optical power to reach the first optical circulator and 10% of the optical power to reach the second optical circulator.

[0015] Furthermore, the second beam splitter is a 50:50 beam splitter.

[0016] Furthermore, the detection module has a lateral resolution of 17.5 μm, a longitudinal resolution of 8.34 μm, an imaging depth of 5 mm, and a signal-to-noise ratio of 94.34 dB.

[0017] Furthermore, the material of the liner is either a mixture of epoxy resin and tungsten powder or a mixture of ferrite powder and rubber powder.

[0018] A second aspect of the present invention provides a method for measuring skin elasticity and moisture content, implemented using the aforementioned optical device for measuring skin elasticity and moisture content, the method comprising:

[0019] The ultrasonic transducer in the control excitation module, under the action of the function signal generator and power amplifier, emits ultrasonic excitation that acts on the skin tissue of the tester, causing the skin tissue to vibrate and generate shear waves. The sweeping laser in the control detection module emits a detection beam, which is used to pass through the first three-pole polarization controller and the first beam splitter in sequence. The first beam splitter is used to split the detection beam into two beams. One beam is acted on the skin tissue of the tester by the first optical circulator, the second three-pole polarization controller, the collimating lens, the scanning galvanometer, the convex lens and the ultrasonic transducer, and reflects the feedback beam. The other beam is reached by the second optical circulator, the third three-pole polarization controller, the variable aperture and the plano-convex mirror of the reference module, and reflects the reference beam.

[0020] The reference beam and the feedback beam are acquired, and the optical path difference between the detection module and the reference module is adjusted according to the reference beam and the feedback beam to obtain a target detection image;

[0021] The wave velocity of the shear wave in the feedback beam is obtained, and the shear modulus is calculated based on the wave velocity; the shear modulus is input into the mapping model to obtain the skin elasticity and water content.

[0022] Furthermore, in the step of obtaining the wave velocity of the shear wave in the feedback beam and calculating the shear modulus based on the wave velocity, the formula for calculating the shear modulus is:

[0023] E = 3ρV 2 ;

[0024] Where E is the shear modulus, ρ is the density of biological tissue, and V is the shear wave velocity.

[0025] Furthermore, in the step of acquiring the reference beam and the feedback beam, and adjusting the optical path difference between the detection module and the reference module based on the reference beam and the feedback beam to obtain the detection image, the formula for calculating the strain tensor in each direction of the detection image is:

[0026]

[0027]

[0028]

[0029] Where v represents Poisson's ratio, σ xxLet σ be the component of the stress tensor in the x-direction. yy σ is represented by the component of the stress tensor in the yy direction. zz Let σ be the component of the stress tensor in the z-direction. xy σ is represented by the components of the stress tensor in the xy direction. yz σ is represented by the components of the stress tensor in the yz direction. zx Let e ​​be the component of the stress tensor in the zx direction. xx Let e ​​be the component of the strain tensor in the x-direction. yy Let e ​​be the component of the strain tensor in the yy direction. zz Let e ​​be the component of the strain tensor in the z-direction. xy Let e ​​be the component of the strain tensor in the xy direction. yz E is represented as the component of the strain tensor in the yz direction. zx It is represented as the component of the strain tensor in the zx direction.

[0030] The beneficial effects of this invention are as follows: The device includes a reference module, a control module, and an excitation module, a detection module, and a receiving module electrically connected to the control module. Under the control of the control module, the excitation module emits ultrasonic excitation that acts on the skin tissue of the test subject, causing the skin tissue to vibrate and generate shear waves. At the same time, under the control of the control module, the detection module emits a detection beam, which, after passing through an ultrasonic transducer, acts on the skin tissue of the human test subject and reflects a feedback beam. The detection beam is used to detect the shear waves. Under the control of the control module, the receiving module detects the feedback beam and the reference beam. Finally, through the measurement results of the shear waves, non-contact, quantitative, and accurate measurement of skin elasticity and water content is achieved. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of an optical device for measuring skin elasticity and moisture content provided in Embodiment 1 of the present invention;

[0032] Figure 2 This is a schematic diagram of the ultrasonic transducer provided in Embodiment 1 of the present invention;

[0033] Figure 3 This is a flowchart illustrating the implementation of a method for measuring skin elasticity and moisture content according to Embodiment 2 of the present invention.

[0034] Explanation of key component symbols:

[0035]

[0036]

[0037] The following detailed embodiments will be further described in conjunction with the above-mentioned accompanying drawings. Detailed Implementation

[0038] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0039] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] Example 1

[0042] Please see Figure 1 and Figure 2 , Figure 1 This diagram illustrates the structure of an optical device for measuring skin elasticity and moisture content according to Embodiment 1 of the present invention. Figure 2 A schematic diagram of the structure of an ultrasonic transducer provided in Embodiment 1 of the present invention is shown. The optical device includes a reference module, a control module 1, and an excitation module, a detection module, and a receiving module that are electrically connected to the control module 1. In this embodiment, the control module 1 can be a computer, which is electrically connected to the swept laser 2 of the detection module, the balanced detector 18 of the receiving module, and the function signal generator 19 of the excitation module, respectively, for controlling them.

[0043] Specifically, the excitation module includes a function signal generator 19, a power amplifier 20, and an ultrasonic transducer 10, which are connected in sequence. The ultrasonic transducer 10, under the action of the function signal generator 19 and the power amplifier 20, emits ultrasonic excitation that acts on the skin tissue 11 of the test subject, causing the skin tissue 11 to vibrate and generate shear waves. The detection module includes a swept-frequency laser 2, a first three-propeller polarization controller 3, a first beam splitter 4, a first optical circulator 5, a second three-propeller polarization controller 6, a collimating lens 7, a scanning galvanometer 8, and a convex lens 9, which are connected in sequence. The convex lens 9 is optically connected to the ultrasonic transducer 10. The detection beam emitted from the convex lens 9 passes through the ultrasonic transducer 10 and acts on the skin tissue 11 of the test subject. The reflected feedback beam and the detection beam are used to detect shear waves. The reference module includes a second optical circulator 12 connected to the first beam splitter 4, and a third three-propeller polarization controller 13, a variable aperture 14, a plano-convex mirror 15, and a dielectric film reflector 16 connected to the second optical circulator 12 in sequence. The receiving module includes a second beam splitter 17 connected to the first optical circulator 5 and the second optical circulator 12 in optical paths, and a balanced detector 18 connected to the second beam splitter 17 in optical path. The balanced detector 18 is used to detect the feedback beam emitted by the first optical circulator 5 and the reference beam emitted by the second optical circulator 12. The control module 1 is electrically connected to the swept laser 2, the balanced detector 18, and the function signal generator 19 in optical paths.

[0044] In this embodiment, the scanning laser in the detection module has a center wavelength of 1310nm and a bandwidth of 100nm, enabling more sensitive and rapid measurement of shear wave propagation on tissue. Since a beam is used, it is a non-contact method, which is safer and more hygienic compared to traditional contact methods. Specifically, the laser light power emitted by the scanning laser is 20mW. The 1310nm laser first passes through the first three-paddle polarization controller 3. By adjusting the first three-paddle polarization controller 3, the polarization state of the laser can be adjusted. Then, it passes through a 90:10 beam splitter to divide the laser light power into 90% and 10%. It should be noted that 90% of the light power will reach the first optical circulator 5 of the detection module, and 10% of the light power will reach the second optical circulator 12 of the reference module. That is, 90% of the light power reaches the sample arm, and 10% of the light power reaches the reference arm. Furthermore, the light reaching the sample arm passes through interface one of the first optical circulator 5 and is output with low attenuation from interface two of the first optical circulator 5 to the second three-paddle polarization controller 6. The second three-paddle polarization controller 6 can adjust the interference Gaussian envelope state of the light from the sample arm and the reference arm to obtain the highest signal-to-noise ratio and make the imaging clear. In addition, during the image imaging process, the light passing through the second three-paddle polarization controller 6 reaches the scanning galvanometer 8. The scanning galvanometer 8 is composed of an X-axis scanning galvanometer 8 and a Y-axis scanning galvanometer 8, which constitute the two-dimensional scanning area. The rotation of the X-axis scanning galvanometer 8 and the Y-axis scanning galvanometer 8 is controlled by the NI card for rotation scanning. The scanning area is set in the computer operation interface. The light emitted from the scanning galvanometer 8 passes through the convex lens 9 and the transparent ultrasonic transducer 10 in sequence, and acts on the skin area to detect the shear wave generated by the transparent ultrasonic transducer 10. It should be noted that during the image imaging process, the detection module has a horizontal resolution of 17.5μm, a vertical resolution of 8.34μm, an imaging depth of 5mm, a signal-to-noise ratio of 94.34dB, and a maximum acquisition speed of 1Gs / s for the data acquisition card.

[0045] Furthermore, when the excitation is applied to the skin, the position of the excitation needs to be adjusted on the computer interface to ensure that the probe beam can detect the propagation of the shear wave. During the detection process, the size and position of the excitation need to be adjusted according to the detection situation to ensure that the detected excitation is not too large or too small, and that the excitation signal can be seen in the image. Specifically, 10% of the light power emitted by the first beam splitter 4 reaches the first interface of the second optical circulator 12 and enters the reference arm from the second interface of the second optical circulator 12. That is, the third three-paddle polarization controller 13, the variable aperture 14, the plano-convex mirror 15 and the dielectric film reflector 16 are sequentially connected to the second optical circulator 12. The collimating lens 7 in the detection module is adjusted to match the optical path difference between the reference arm and the sample arm. When the optical path difference is zero, the interference signal is the strongest and the quality of the obtained detection image is the best. The surface of the dielectric film reflector 16 is coated with a layer of gold material, so that the reflectivity of the dielectric film reflector 16 reaches 90%.

[0046] In this embodiment, the probe beam from the sample arm, which sequentially passes through the second three-propeller polarization controller 6, collimating lens 7, scanning galvanometer 8, convex lens 9, and ultrasonic transducer 10, reaches the skin area and generates a feedback beam. The feedback beam sequentially passes through the ultrasonic transducer 10, convex lens 9, scanning galvanometer 8, collimating lens 7, and the second three-propeller polarization controller 6 to reach the second interface of the first optical circulator 5, and is emitted from the third interface of the first optical circulator 5 to reach the second beam splitter 17. The second beam splitter 17 is a 50:50 beam splitter, which interferes with the reference beam reflected back from the reference arm and outputs to the V+ and V- terminals of the balanced detector 18. Specifically, the balanced detector 18 converts the received optical signal into an electrical signal, amplifies the AC signal, and filters out the DC signal.

[0047] It should be noted that the ultrasonic transducer 10 includes a housing 29, a padding 21, a backing 22, an electrode 28, a piezoelectric crystal 23, an acoustic matching layer 24, a protective layer 25, and a lens 26, which are stacked sequentially within the housing 29. The lens 26 in the ultrasonic transducer 10 is a convex lens 9. Electrode 28 extends outwards with electrode wires 27, meaning that a lead wire is welded to the upper and lower poles of electrode 28, respectively, and connects to the electrode insert on the housing 29 to transmit electrical signals. The piezoelectric crystal 23 is made of transparent epoxy resin and is circular and convex. A coil is disposed on the outside of the piezoelectric crystal 23 to complete the acoustic-to-electric conversion, transmitting mechanical energy to the crystal to generate ultrasonic waves. Sound waves act on human skin. The material of the pad 21 is either a mixture of epoxy resin and tungsten powder or a mixture of ferrite powder and rubber powder. It is a sound-absorbing material that can attenuate and absorb the ultrasonic energy radiated from the piezoelectric crystal 23. Specifically, the side wall of the pad 21 has a wiring hole through which the electrode wire 27 passes. The outer shell 29 is distributed on the outermost layer of the ultrasonic transducer 10, providing support for the internal materials of the probe. It is connected to the internal piezoelectric crystal 23, protective layer 25, and pad 21. The outer shell 29 fixes the cable lead and also serves to support, accommodate, insulate, bear pressure, and protect the transducer.

[0048] In this embodiment, the sound-absorbing material mentioned above has the following properties: it can make the pad 21 have a large attenuation capacity, and the ultrasonic energy will not be reflected back and forth in the probe, but will be absorbed by the sound-absorbing material; it has an impedance close to that of the piezoelectric material, and the same impedance can make all the sound waves radiated by the piezoelectric crystal 23 enter the pad 21 and no longer be reflected back into the crystal. The advantage is that the acoustic radiation force of the transparent ultrasonic transducer 10 can be more stable, and the generated ultrasonic excitation can be better focused on the skin area. In addition, a protective layer 25 is provided on the side of the transparent ultrasonic transducer 10 near the skin. The material used is a material with a low attenuation coefficient and wear resistance. The protective layer 25 can also serve as an acoustic impedance gradient layer. The thickness is one-quarter of the wavelength. The protective layer 25 has the following properties: it is wear-resistant, protecting the internal components of the transparent ultrasonic transducer 10 from damage; it has the optimal thickness with good transmittance when the transparent ultrasonic transducer 10 generates ultrasonic excitation; the acoustic impedance of the protective layer 25 is close to the acoustic impedance of human tissue, which reduces the energy attenuation of ultrasonic waves during transmission, so that the ultrasonic excitation can still generate a certain excitation when it reaches the skin and can be detected synchronously by the optical detection device.

[0049] In summary, the optical device for measuring skin elasticity and moisture content in the above embodiments of the present invention, under the control of the control module, emits ultrasonic excitation that acts on the skin tissue of the test subject, causing the skin tissue to vibrate and generate shear waves. At the same time, under the control of the control module, the detection module emits a detection beam, which, after passing through an ultrasonic transducer, acts on the skin tissue of the test subject and reflects a feedback beam. The detection beam is used to detect the shear waves, while the receiving module, under the control of the control module, detects the feedback beam and the reference beam. Finally, through the measurement results of the shear waves, non-contact, quantitative, and accurate measurement of skin elasticity and moisture content is achieved.

[0050] Example 2

[0051] Please see Figure 3 The above is a flowchart of a method for measuring skin elasticity and moisture content provided in Embodiment 2 of the present invention. The method specifically includes steps S201 to S205.

[0052] In step S201, the ultrasonic transducer in the control excitation module emits ultrasonic excitation under the action of the function signal generator and the power amplifier, which acts on the skin tissue of the test subject, causing the skin tissue to vibrate and generate shear waves.

[0053] First, determine the area of ​​skin tissue to be tested, adjust the angle of the ultrasound transducer acting on the skin tissue area, and simultaneously adjust the distance of the ultrasound excitation to the skin tissue area to be tested, i.e., the focal length, to generate acoustic radiation force on the skin tissue, causing the piezoelectric crystal of the transparent ultrasound transducer to enter a vibrating state, radiating sound waves into the medium, acting on the skin area, and causing appropriate skin vibration. Among them, the acoustic radiation force generated by the transparent ultrasound transducer acts on the skin tissue area to be tested, inducing tissue deformation and generating shear waves at the same time.

[0054] Step S202: The sweeping laser in the detection module emits a detection beam. The detection beam passes sequentially through a first three-paddle polarization controller and a first beam splitter. The first beam splitter splits the detection beam into two beams. One beam, consisting of a first optical circulator, a second three-paddle polarization controller, a collimating lens, a scanning galvanometer, a convex lens, and the ultrasonic transducer, acts on the skin tissue of the subject and reflects a feedback beam. The other beam, consisting of a second optical circulator, a third three-paddle polarization controller, a variable aperture, and a plano-convex mirror in the reference module, reaches the dielectric film reflector and reflects a reference beam.

[0055] Specifically, the scanning galvanometer consists of an X-axis scanning galvanometer and a Y-axis scanning galvanometer. As the X-axis and Y-axis rotate, a two-dimensional plane can be scanned and detected in the area of ​​the skin tissue to be tested. Through two-dimensional scanning, shear waves generated by acoustic radiation force on the skin tissue can be detected.

[0056] In addition, the optical fiber is wound three times on each of the three propellers of the first, second, and third three-propeller polarization controllers. The three rotating propellers can rotate back and forth. The first rotating propeller is used to change the polarization state of the light and adjust it to linearly polarized light. The second rotating propeller is used to change the polarization direction of the light. The third rotating propeller is used to transform input light with arbitrary polarization state into output light with arbitrary state.

[0057] Step S203: Obtain the reference beam and the feedback beam; adjust the optical path difference between the detection module and the reference module according to the reference beam and the feedback beam to obtain a target detection image.

[0058] Step S204: Obtain the wave velocity of the shear wave in the feedback beam, and calculate the shear modulus based on the wave velocity.

[0059] In this embodiment, under the action of the detection beam emitted by the detection module, the shear wave on the skin tissue can be reacted to, generating a feedback beam. This feedback beam contains wave velocity information, and the shear modulus is calculated based on this wave velocity information. Specifically, the formula for calculating the shear modulus is as follows:

[0060] E = 3ρV 2 ;

[0061] Where E is the shear modulus, ρ is the density of biological tissue, and v is the shear wave velocity.

[0062] Specifically, the target detection image obtains the stress and strain of skin tissue in different directions, and then performs distributed imaging reconstruction of its elastic modulus. The formula for calculating the strain tensor in each direction of the detection image is as follows:

[0063]

[0064]

[0065]

[0066] Where v represents Poisson's ratio, σ xx Let σ be the component of the stress tensor in the x-direction. yy σ is represented by the component of the stress tensor in the yy direction. zz Let σ be the component of the stress tensor in the z-direction. xy σ is represented by the components of the stress tensor in the xy direction. yz σ is represented by the components of the stress tensor in the yz direction. zx Let e ​​be the component of the stress tensor in the zx direction. xx Let e ​​be the component of the strain tensor in the x-direction. yyLet e ​​be the component of the strain tensor in the yy direction. zz Let e ​​be the component of the strain tensor in the z-direction. xy Let e ​​be the component of the strain tensor in the xy direction. yz E is represented as the component of the strain tensor in the yz direction. zx It is represented as the component of the strain tensor in the zx direction.

[0067] Step S205: Input the shear modulus into the mapping model to obtain skin elasticity and water content.

[0068] It should be noted that a mapping model is established in advance. This involves conducting extensive tests on the shear modulus, skin elasticity, and water content of different skin tissues. The test results of the shear modulus are then correlated with the test results of the skin elasticity and water content to form a corresponding relationship, i.e., a fitting relationship, in order to complete the establishment of the mapping model.

[0069] In addition, by measuring the elastic modulus of skin tissue and inputting it into the mapping model, the corresponding skin elasticity and water content can be obtained. At the same time, it can also output corresponding skin care suggestions based on different skin elasticity and water content.

[0070] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0071] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An optical device for measuring skin elasticity and moisture content, characterized in that, The device includes an excitation module comprising a function signal generator, a power amplifier, and an ultrasonic transducer connected in sequence. The ultrasonic transducer is used to emit ultrasonic excitation under the action of the function signal generator and the power amplifier to act on the skin tissue of the tester, causing the skin tissue to vibrate and generate shear waves. The detection module includes a swept-frequency laser, a first three-pole polarization controller, a first beam splitter, a first optical circulator, a second three-pole polarization controller, a collimating lens, a scanning galvanometer, and a convex lens, which are connected in sequence via optical paths. The convex lens is connected to the optical path of the ultrasonic transducer. The detection beam emitted from the convex lens passes through the ultrasonic transducer, acts on the skin tissue of the subject, and reflects a feedback beam. The detection beam is used to detect the shear wave. The reference module includes a second optical circulator connected to the first beam splitter optical path, and a third three-paddle polarization controller, a variable aperture, a plano-convex mirror, and a dielectric film reflector connected sequentially to the second optical circulator optical path. The receiving module includes a second beam splitter connected to the optical paths of the first optical circulator and the second optical circulator respectively, and a balanced detector connected to the optical path of the second beam splitter. The balanced detector is used to detect the feedback beam emitted by the first optical circulator and the reference beam emitted by the second optical circulator. The control module is used to be electrically connected to the swept laser, the balanced detector and the function signal generator respectively.

2. The optical device for measuring skin elasticity and moisture content according to claim 1, characterized in that, The scanning laser has a center wavelength of 1310nm and a bandwidth of 100nm.

3. The optical device for measuring skin elasticity and moisture content according to claim 2, characterized in that, The ultrasonic transducer includes a housing, a pad, a backing, an electrode, a piezoelectric crystal, an acoustic matching layer, a protective layer, and a lens, which are stacked sequentially within the housing. The electrode extends outward with electrode wires. The piezoelectric crystal is made of transparent epoxy resin and is convex in shape. A coil is disposed on the outside of the piezoelectric crystal.

4. The optical device for measuring skin elasticity and moisture content according to claim 3, characterized in that, The first beam splitter is a 90:10 beam splitter, wherein the first beam splitter is used to control 90% of the optical power to reach the first optical circulator and 10% of the optical power to reach the second optical circulator.

5. The optical device for measuring skin elasticity and moisture content according to claim 4, characterized in that, The second beam splitter is a 50:50 beam splitter.

6. The optical device for measuring skin elasticity and moisture content according to claim 5, characterized in that, The detection module has a lateral resolution of 17.5 μm, a longitudinal resolution of 8.34 μm, an imaging depth of 5 mm, and a signal-to-noise ratio of 94.34 dB.

7. The optical device for measuring skin elasticity and moisture content according to claim 3, characterized in that, The liner material is any one of a mixture of epoxy resin and tungsten powder or a mixture of ferrite powder and rubber powder.

8. A method for measuring skin elasticity and moisture content, implemented using the optical device for measuring skin elasticity and moisture content as described in any one of claims 1-7, characterized in that, The method includes: controlling the ultrasonic transducer in the excitation module to emit ultrasonic excitation under the action of a function signal generator and a power amplifier, which acts on the skin tissue of the tester, causing the skin tissue to vibrate and generate shear waves; The sweeping laser in the control detection module emits a detection beam, which is used to pass sequentially through a first three-pole polarization controller and a first beam splitter. The first beam splitter splits the detection beam into two beams. One beam is formed by a first optical circulator, a second three-pole polarization controller, a collimating lens, a scanning galvanometer, a convex lens, and the ultrasonic transducer, acting on the skin tissue of the subject and reflecting a feedback beam. The other beam is formed by a second optical circulator, a third three-pole polarization controller, a variable aperture, and a plano-convex mirror in the reference module, reaching a dielectric film reflector and reflecting a reference beam. The reference beam and the feedback beam are acquired, and the optical path difference between the detection module and the reference module is adjusted according to the reference beam and the feedback beam to obtain a target detection image; The wave velocity of the shear wave in the feedback beam is obtained, and the shear modulus is calculated based on the wave velocity; the shear modulus is input into the mapping model to obtain the skin elasticity and water content.

9. The method for measuring skin elasticity and moisture content according to claim 8, characterized in that, In the step of obtaining the wave velocity of the shear wave in the feedback beam and calculating the shear modulus based on the wave velocity, the formula for calculating the shear modulus is as follows: E=3ρV 2 ; Where E is the shear modulus, ρ is the density of biological tissue, and V is the shear wave velocity.

10. The method for measuring skin elasticity and moisture content according to claim 9, characterized in that, In the step of acquiring the reference beam and the feedback beam, and adjusting the optical path difference between the detection module and the reference module based on the reference beam and the feedback beam to obtain a detection image, the formula for calculating the strain tensor in each direction of the detection image is as follows: Where v represents Poisson's ratio, σ xx Let σ be the component of the stress tensor in the x-direction. yy σ is represented by the component of the stress tensor in the yy direction. zz Let σ be the component of the stress tensor in the z-direction. xy σ is represented by the components of the stress tensor in the xy direction. yz Let σ be the component of the stress tensor in the yz direction. zx Let e ​​be the component of the stress tensor in the zx direction. xx Let e ​​be the component of the strain tensor in the x-direction. yy Let e ​​be the component of the strain tensor in the yy direction. zz Let e ​​be the component of the strain tensor in the z-direction. xy Let e ​​be the component of the strain tensor in the xy direction. yz E is represented as the component of the strain tensor in the yz direction. zx It is represented as the component of the strain tensor in the zx direction.

Images