A calibration device and a calibration method thereof

Abstract

The application discloses a calibration device and a calibration method thereof, and relates to the technical field of calibration devices, and specifically discloses the following technical scheme: a temperature and humidity control box is used for maintaining preset temperature and humidity conditions; a calibration unit is located in the temperature and humidity control box and comprises a biomimetic material layer and a waterproof and breathable film, the biomimetic material layer is used for providing a stable moisture reference, the waterproof and breathable film is covered on the biomimetic material layer to form a calibration reference interface and is used for establishing a stable water vapor pressure gradient; a controllable linear motion unit is arranged in the temperature and humidity control box and can drive a probe to move in a vertical direction; a fixed adjustment unit is connected with the controllable linear motion unit and is used for fixing the probe and adjusting an attitude angle of the probe; and a pressure control unit is used for controlling contact pressure between the probe and the calibration reference interface of the calibration unit. The application constructs a simulated skin interface through the biomimetic material layer and the waterproof and breathable film, realizes complete metrological traceability, unifies calibration conditions and actual measurement conditions, and improves repeatability and reproducibility of calibration results.

Description

Technical Field

[0001] This application belongs to the field of metrology and testing technology, and in particular relates to a calibration device and its calibration method. Background Technology

[0002] Objective measurement of skin moisture parameters is crucial in fields such as cosmetics research and development, dermatology, and drug efficacy evaluation. Currently, the industry commonly uses specialized instruments based on different principles for measurement. Among the most representative are: skin moisture content probes based on capacitance measurement, which reflect the surface moisture content of the skin by measuring changes in the skin's dielectric constant; and transepidermal water loss probes based on vapor pressure gradient measurement, which calculate transepidermal water loss rate by measuring the water vapor pressure gradient on the skin surface and are a core indicator for assessing skin barrier function. Regular calibration of these instruments is essential to ensure the accuracy and comparability of the measurement data.

[0003] Current calibration methods for skin moisture measuring instruments primarily rely on manufacturer-provided standard parts or internal electronic zero-point calibration. However, these existing calibration methods have the following shortcomings: First, the measurement value transfer chain of standard parts provided by manufacturers is not transparent, and third-party testing institutions cannot establish an independent metrological traceability system, making it difficult to issue credible calibration reports; Second, the calibration process is usually carried out in a normal temperature and humidity environment, which fails to simulate the skin physiological temperature and humidity conditions faced by the probe during actual measurement, resulting in a difference between the calibration conditions and the usage conditions. Third, key parameters such as probe placement angle and contact pressure lack standardized control methods, and the repeatability and reproducibility of calibration results largely depend on the operator's experience.

[0004] Therefore, there is a need for a skin moisture probe calibration technology that can provide independent metrological traceability, simulate the real physiological environment, and achieve standardized operation. Summary of the Invention

[0005] The purpose of this application is to provide a calibration device and calibration method thereof, which can achieve integrated calibration of probes based on different principles (such as capacitance method and vapor pressure gradient method) under standard conditions.

[0006] To achieve the above objectives, this application adopts the following technical solution: A calibration device for calibrating a probe for testing skin moisture parameters, the calibration device comprising: a temperature and humidity control chamber for maintaining a calibration area under preset temperature and humidity conditions; a calibration unit located within the temperature and humidity control chamber, comprising a biomimetic material layer and a waterproof and breathable membrane, the biomimetic material layer providing a stable moisture reference, and the waterproof and breathable membrane covering the biomimetic material layer to form a calibration reference interface and for establishing a stable water vapor pressure gradient; a controllable linear motion unit disposed within the temperature and humidity control chamber, capable of driving the probe to move vertically; a fixing and adjusting unit connected to the controllable linear motion unit for fixing the probe and also for adjusting the probe's posture angle; and a pressure control unit for controlling the contact pressure between the probe and the calibration reference interface of the calibration unit.

[0007] In this solution, a constant temperature and humidity environment is provided by a temperature and humidity control box, a biomimetic material layer and a waterproof and breathable membrane construct a stable and uniform "simulated skin" interface, a controllable linear motion unit and a pressure control unit realize the precise positioning and standardized contact of the probe, and a fixed adjustment unit ensures the vertical posture of the probe, thereby realizing independent, traceable and standardized calibration of the skin moisture probe.

[0008] Furthermore, the calibration unit also includes: a lower base, disposed at the bottom of the temperature and humidity control box, with a groove on its top, in which the biomimetic material layer is housed; and an upper cover, disposed on the lower base, for pressing and fixing the waterproof and breathable membrane onto the biomimetic material layer, with a test hole on the top of the upper cover for the probe to contact the waterproof and breathable membrane.

[0009] In this design, the fixing method is simple and reliable. The groove in the lower base ensures the positioning accuracy of the biomimetic material layer, and the upper cover ensures the flatness of the waterproof and breathable membrane surface, thus improving the stability of the calibration benchmark.

[0010] Furthermore, the biomimetic material layer is a sponge sheet containing sodium polyacrylate solution; the water vapor permeability of the waterproof and breathable membrane is 8-22 g / m³. 2 Within the range of h.

[0011] In this scheme, the biomimetic material layer prepared by dripping sodium polyacrylate solution onto a sponge sheet can provide a stable moisture baseline for a long time; the water vapor transmission rate of the waterproof and breathable membrane is 8-22 g / m³. 2 •h is close to the actual permeability of the stratum corneum of human skin, ensuring the biomimeticity of the vapor pressure gradient.

[0012] Furthermore, the fixing adjustment unit includes a clamping structure and a fixing arm; one end of the fixing arm is connected to the clamping structure, which is used to clamp and fix the probe; the other end of the fixing arm is provided with a rotating joint, and is rotatably connected to the controllable linear motion unit through the rotating joint; the rotating joint is equipped with a joint limiter for locking its rotation angle.

[0013] In this design, one end of the fixed arm, i.e. the front end, clamps the fixed probe through a clamping structure, while the other end of the fixed arm, i.e. the rear end, is rotatably connected to the controllable linear motion unit through a rotary joint. The rotary joint allows the probe to adjust its posture in multiple directions, providing a high degree of freedom of adjustment. After the joint limiter is locked, it can withstand the reaction force of the probe during the descent process, ensuring that the angle does not change.

[0014] Furthermore, the clamping structure includes: a first joint housing formed by the mating of a front arc-shaped clamp and a rear arc-shaped clamp, and a first inner liner formed by the mating of a front arc-shaped pad and a rear arc-shaped pad; the first inner liner is disposed inside the first joint housing, and the outer curved surface of the first inner liner is in contact with the inner curved surface of the first joint housing, and the inner curved surface of the first inner liner is in contact with the probe surface; the front arc-shaped clamp and the rear arc-shaped clamp are detachably fixed together by a first fastener; a first locking member is respectively provided between the front arc-shaped clamp and the front arc-shaped pad, and between the rear arc-shaped clamp and the rear arc-shaped pad.

[0015] Furthermore, the fixed arm has a plug-in groove at one end for connecting to the clamping structure; the end of the front arc-shaped clamp or the rear arc-shaped clamp is connected to a plug-in rod adapted to the plug-in groove; the depth of the plug-in rod inserted into the plug-in groove is used to adjust the horizontal position of the clamping structure; the plug-in rod and the plug-in groove are fixed by a limiting member.

[0016] Furthermore, the calibration device also includes: a horizontal observation sleeve fitted on the probe for indicating the vertical state of the probe; and / or a horizontal adjustment unit disposed on the temperature and humidity control box for adjusting the horizontal state of the temperature and humidity control box.

[0017] In this design, the horizontal observation sleeve is directly mounted on the probe, allowing for real-time observation of the probe's vertical status, making the operation intuitive.

[0018] Further, the horizontal observation sleeve includes: a second joint shell formed by the mating of a first arc-shaped clip and a second arc-shaped clip; a second inner liner formed by the mating of a first arc-shaped pad and a second arc-shaped pad; and a probe level disposed on the first arc-shaped clip or the second arc-shaped clip and used to indicate the vertical state of the probe; the second inner liner is disposed inside the second joint shell, and the outer curved surface of the second inner liner is in contact with the inner curved surface of the second joint shell, and the inner curved surface of the second inner liner is in contact with the probe surface; the first arc-shaped clip and the second arc-shaped clip are detachably fixed together by a second fastener; A second locking element is provided between the first arc-shaped clamp and the first arc-shaped gasket, and between the second arc-shaped clamp and the second arc-shaped gasket.

[0019] Furthermore, the leveling unit includes: a box level, which is disposed at the inner bottom of the temperature and humidity control box, for indicating the horizontal state of the temperature and humidity control box; and adjustable support feet, which are disposed at the outer bottom of the temperature and humidity control box, for adjusting the height of the temperature and humidity control box according to the box level to keep it in a horizontal state.

[0020] In this design, a stable support plane is formed by adjustable support legs, and the height of these adjustable support legs can be adjusted to achieve precise leveling; the box level indicator visually indicates the level status and is easy to operate.

[0021] This application also provides a method for calibrating a skin moisture parameter testing probe using the above-mentioned calibration device, comprising the following steps: adjusting the calibration area of ​​the temperature and humidity control box to a preset temperature and humidity condition and keeping it stable, wherein the preset temperature and humidity condition is a temperature of 37°C and a relative humidity of 50%RH; adjusting the orientation of the probe to make it vertical and keeping it fixed; preparing a biomimetic material layer with defined water absorption properties; assembling the biomimetic material layer and the waterproof and breathable membrane to form a calibration reference interface; under stable environmental conditions, controlling the probe to contact the calibration reference interface with a preset pressure, wherein the preset pressure is the standard measurement pressure of the probe; maintaining the contact pressure until the measurement is completed, and then releasing the contact.

[0022] This method achieves complete standardization of the calibration process through a standardized operating procedure of "leveling adjustment → environmental stabilization → probe posture adjustment → calibration reference preparation → pressure-controlled contact → measurement," eliminating random errors introduced by different operator techniques and improving the repeatability and reproducibility of calibration results. Simultaneously, 37℃ is close to the core temperature of human skin, and 50%RH is the typical humidity environment for human skin; this combination of parameters ensures that the calibration conditions are highly consistent with actual measurement conditions, minimizing systematic errors. The standard measurement pressure ensures that the calibration conditions are consistent with actual usage conditions, improving calibration accuracy.

[0023] Beneficial effects (1) A biomimetic calibration benchmark was created: A stable and uniform "simulated skin" interface was constructed through a structure of "constant temperature and humidity biomimetic material layer + waterproof and breathable membrane". This interface not only provides a stable moisture source (for capacitance method calibration), but also establishes a physiologically consistent vapor pressure gradient (for TEWL calibration), unifying the calibration conditions with the actual measurement conditions and eliminating systematic errors introduced by environmental mismatch. It is used to simultaneously calibrate skin moisture content probes based on capacitance measurement and transdermal water loss probes based on vapor pressure gradient.

[0024] (2) Complete metrological traceability is achieved: The calibration reference of the device is defined by physical parameters (temperature, humidity, pressure) that can be precisely controlled and quantified. These parameters can be directly traced to national / international metrological standards, thus providing testing institutions with an independent and reliable traceability basis, solving the problem of dependence on manufacturer calibration parts, and enabling third-party testing institutions to issue credible calibration reports.

[0025] (3) Improved calibration accuracy and repeatability: By integrating horizontal correction and pressure feedback control, the two key variables of probe placement angle and pressure are standardized, which fundamentally eliminates random errors introduced by different operator techniques, greatly improves the repeatability and reproducibility of calibration results, and ensures the consistency of calibration results for different operators or different operations.

[0026] (4) Integrated multi-functional calibration: This device ingeniously integrates the calibration requirements of probes with two different measurement principles into a unified physical model, providing an efficient and integrated calibration platform, reducing the equipment cost and operational complexity of the testing institution, and improving the efficiency of calibration work. Attached Figure Description

[0027] Figure 1 This diagram shows a structural schematic of a calibration device in this embodiment; Figure 2 A cross-sectional schematic diagram of the calibration unit in this embodiment is shown; Figure 3 A cross-sectional schematic diagram of the fixed adjustment unit in this embodiment is shown; Figure 4 This is a schematic cross-sectional view of the horizontal observation sleeve in this embodiment.

[0028] Figure Labels 10. Temperature and humidity control box; 11. Temperature and humidity controller; 12. Temperature and humidity sensor; 13. Rubber threaded sealing plug; 20. Calibration unit; 21. Bionic material layer; 22. Waterproof and breathable membrane; 23. Lower base; 231. Groove; 24. Upper cover; 241. Test hole; 30. Controllable linear motion unit; 40. Fixing and adjustment unit; 41. Clamping structure; 411. Front arc-shaped clamp; 412. Rear arc-shaped clamp; 413. Front arc-shaped gasket; 414. Rear arc-shaped gasket; 415. First fastener; 416. 417. Locking component; 418. Connecting rod; 419. Limiting component; 42. Fixing arm; 421. Connecting slot; 43. Rotating joint; 44. Joint limiter; 50. Pressure control unit; 60. Probe; 61. Probe connecting cable; 70. Horizontal observation sleeve; 71. First arc-shaped clamp; 72. Second arc-shaped clamp; 73. First arc-shaped gasket; 74. Second arc-shaped gasket; 75. Probe level; 76. Second fastener; 77. Second locking component; 80. Horizontal adjustment unit; 81. Box level; 82. Adjustable support foot. Detailed Implementation

[0029] The technical solutions of this application are further illustrated below through specific embodiments. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0030] It should be noted that the technical terms in the following embodiments are defined as follows: A temperature and humidity control box is a closed box that can precisely control the internal temperature and relative humidity.

[0031] The biomimetic material layer refers to a material layer with stable water absorption and release properties, which is made by dripping sodium polyacrylate solution onto a sponge sheet.

[0032] Waterproof and breathable membranes are membrane materials with selective permeability, allowing water vapor to pass through but preventing liquid water from passing through.

[0033] A servo electric cylinder is a precision linear motion device driven by a servo motor, which can achieve high-precision position and force control.

[0034] A ball joint is a mechanical connection structure that achieves multi-degree-of-freedom angle adjustment through ball-and-socket mating.

[0035] Please refer to Figure 1As shown, this embodiment provides a calibration device for calibrating a probe 60 for testing skin moisture parameters. The top of the probe 60 is connected to a probe connection cable 61. The calibration device includes a temperature and humidity control box 10, a calibration unit 20, a controllable linear motion unit 30, a fixing and adjusting unit 40, and a pressure control unit 50. The temperature and humidity control box 10 is used to maintain the calibration area at preset temperature and humidity conditions. The calibration unit 20 is located inside the temperature and humidity control box 10 and includes a biomimetic material layer 21 and a waterproof and breathable membrane 22. The biomimetic material layer 21 provides a stable moisture reference, and the waterproof and breathable membrane 22 covers the biomimetic material layer 21 to form a calibration reference interface and is used to establish a stable water vapor pressure gradient. The controllable linear motion unit 30 is located inside the temperature and humidity control box 10 and can drive the probe 60 to move vertically. The fixing and adjusting unit 40 is connected to the controllable linear motion unit 30 and is used to fix the probe 60 and also to adjust the posture angle of the probe 60. The pressure control unit 50 is used to control the contact pressure between the probe 60 and the calibration reference interface of the calibration unit 20.

[0036] In this embodiment, the temperature and humidity control box 10 maintains the calibration area under preset temperature and humidity conditions (such as a standard temperature and humidity environment: temperature 37°C, 50%RH). The biomimetic material layer 21 of the calibration unit 20 provides a stable moisture reference. The waterproof and breathable membrane 22 has selective permeability characteristics, and its water vapor permeability is within a preset range, used to simulate the stratum corneum of the skin. The waterproof and breathable membrane 22 covers the biomimetic material layer 21, and the two form a calibration reference interface. That is, through the structure of "bionic material layer 21 + waterproof and breathable membrane 22", a stable and uniform "simulated skin" interface is constructed. The biomimetic material layer 21 provides a stable moisture source for capacitance method probe calibration, and the waterproof and breathable membrane 22 establishes a vapor pressure gradient for vapor pressure gradient method probe calibration. This calibration device can be used to simultaneously calibrate a skin moisture content probe based on capacitance measurement and a transdermal water loss rate probe based on vapor pressure gradient. One device meets the calibration requirements of two probes, reducing equipment costs and operational complexity. During the calibration process, the controllable linear motion unit 30, which integrates the pressure control unit 50 and the fixed adjustment unit 40, controls the probe 60 to contact the calibration reference interface with a vertical posture and standard pressure, thereby providing the testing organization with an independent, traceable, and standardized calibration solution.

[0037] Please continue to refer to Figure 1As shown in this embodiment, it should be noted that the temperature and humidity control box 10 has a rectangular box structure, and the box material is made of a material with good thermal insulation properties. The upper part of the temperature and humidity control box 10 is equipped with a temperature and humidity controller 11 and a temperature and humidity sensor 12. The temperature and humidity controller 11 is a common and feasible standard constant temperature and humidity chamber control unit, which can automatically adjust the temperature and relative humidity inside the chamber according to the set values. The temperature and humidity sensor 12 monitors the temperature and humidity values ​​inside the chamber in real time and feeds the data back to the temperature and humidity controller 11, forming a closed-loop control. The function of the temperature and humidity control box 10 is to provide a constant temperature and humidity environment for the calibration process, simulating the physiological conditions of human skin, thereby ensuring the consistency between the calibration conditions and the actual measurement conditions.

[0038] In some embodiments, the top of the temperature and humidity control box 10 is also provided with an opening, and a rubber wire sealing plug 13 is installed at the opening for the probe connection wire 61 to pass through, and to ensure a certain degree of sealing so that the temperature and humidity can reach the preset conditions.

[0039] In some embodiments, the temperature and humidity control box 10 is further provided with a leveling unit 80, which is used to adjust the level of the temperature and humidity control box 10. The leveling unit 80 includes a box level 81 and adjustable support feet 82. There are four adjustable support feet 82, and their heights are adjustable. The four adjustable support feet 82 are respectively located at the four ends of the temperature and humidity control box 10. The adjustable support feet 82 are fixed to the four bottom corners of the temperature and humidity control box 10 by threaded connection, and the height of each adjustable support foot 82 can be adjusted by rotation. The box level 81 is fixedly installed at the bottom edge of the temperature and humidity control box 10 and is used to indicate the level of the temperature and humidity control box 10. It should be noted that the combined function of the box level 81 and the adjustable support feet 82 is to ensure that the temperature and humidity control box 10 is placed horizontally, thereby ensuring that the calibration reference surface at the bottom of the temperature and humidity control box 10 is horizontal and avoiding measurement errors caused by uneven contact of the probe 60 due to tilting. In addition, the reason for setting the number of adjustable support legs 82 to four is that the four support points can form a stable support plane, and the adjustment process is simple and easy to operate.

[0040] Please continue to refer to Figure 1As shown in this embodiment, it should be noted that the calibration unit 20 includes a biomimetic material layer 21 and a waterproof and breathable membrane 22. The biomimetic material layer 21 is a standard biomimetic absorbent layer, which is a standard circular sponge containing sodium polyacrylate solution. It is prepared by dripping 2 mL of 0.1%~0.5% sodium polyacrylate solution (m / v) onto a sponge sheet with a thickness of 5 mm, a diameter of 3 cm, and a hardness of 25D~35D (the concentration of the sodium polyacrylate solution, the amount added, and the size of the sponge sheet can be adjusted appropriately). Its diameter is slightly larger than the measuring surface of the probe 60. The waterproof and breathable membrane 22 is selected from medical-grade or high-end industrial brands. In this embodiment, the water vapor transmission rate of the selected waterproof and breathable membrane 22 is 8-22 g / m³. 2 The permeability range is close to that of real human skin. The waterproof and breathable membrane 22 is a porous polymer film with pore sizes ranging from nanometers to micrometers. The pore size is small enough to prevent liquid water molecules from passing through, but large enough to allow water vapor molecules to pass freely. The waterproof and breathable membrane 22 covers the biomimetic material layer 21 and is in direct contact with it. While preventing liquid water from seeping out of the surface of the biomimetic material layer 21, it allows water vapor to diffuse outward from the biomimetic material layer 21 through the waterproof and breathable membrane 22 at a stable rate, establishing a stable water vapor pressure gradient above the surface of the waterproof and breathable membrane 22. The function of the waterproof and breathable membrane 22 is to simulate the stratum corneum structure of real skin, which also has the property of preventing liquid water from seeping out but allowing water vapor to pass through.

[0041] Please refer to Figure 1 and Figure 2As shown, in one possible implementation, the calibration unit 20 further includes a lower base 23 and an upper cover 24. The lower base 23 is disposed at the bottom of the temperature and humidity control box 10. A cylindrical groove 231 is formed in the middle of the top of the lower base 23. The biomimetic material layer 21 is placed in the cylindrical groove 231. A waterproof and breathable membrane 22 covers the upper surface of the biomimetic material layer 21, and the coverage area of ​​the waterproof and breathable membrane 22 covers at least the entire upper surface of the biomimetic material layer 21. The upper cover 24 is screwed into place by a thread on its inner circumference that engages with the corresponding thread on the lower base 23 at the outer edge of the groove 231. When the upper cover 24 is tightened, its top inner surface (i.e., the central area of ​​the inner wall of the cover) comes into close contact with the upper surface of the waterproof and breathable membrane 22, thereby pressing and fixing the waterproof and breathable membrane 22 onto the upper surface of the biomimetic material layer 21. This ensures that the surface of the waterproof and breathable membrane 22 is flat and level with the bottom surface of the temperature and humidity control chamber 10, thus ensuring uniform force on the probe 60 during contact and good measurement repeatability. A circular test hole 241 is provided in the middle of the top of the upper cover 24. This hole penetrates the top wall of the upper cover 24, connecting the space above the internal waterproof and breathable membrane 22 with the external environment. The diameter of the test hole 241 is smaller than the exposed area of ​​the waterproof and breathable membrane 22 to ensure that the probe 60 can be stably aligned with the center of the membrane when it passes through the test hole 241 and contacts the waterproof and breathable membrane 22, while avoiding the probe 60 touching the inner wall of the upper cover 24 and causing measurement deviation. It should be noted that the cooperation between the lower base 23 and the upper cover 24 is to fix the biomimetic material layer 21 and the waterproof and breathable membrane 22, to build a stable and uniform calibration reference interface, and to ensure that the initial conditions of the probe 60 are consistent each time it makes contact.

[0042] Please refer to Figure 1 As shown in the illustration, in this embodiment, it should be noted that the controllable linear motion unit 30 is located inside the temperature and humidity control box 10, specifically a servo electric cylinder. The cylinder body of the servo electric cylinder is rigidly connected to the top of the temperature and humidity control box 10, and the piston rod of the servo electric cylinder extends downward in the vertical direction. The servo electric cylinder can achieve high-precision position control and force control.

[0043] In one feasible implementation, the controllable linear motion unit 30 is fixed to the top of the temperature and humidity control box 10 via a pressure control unit 50. In this embodiment, the pressure control unit 50 is specifically a precision pressure controller, which is used to set the descent pressure and movement speed of the servo electric cylinder. The function of the controllable linear motion unit 30 is to drive the probe 60 to move vertically, achieving precise contact between the probe 60 and the waterproof and breathable membrane 22, and ensuring the standardization of the contact pressure through the pressure control unit 50. The servo electric cylinder is selected as the controllable linear motion unit 30 because it has the characteristics of fast response speed, high control accuracy, and smooth movement, which can meet the requirements of the calibration device for position accuracy and force control accuracy.

[0044] Please refer to Figure 1 and Figure 3 As shown in this embodiment, it should be noted that the fixing adjustment unit 40 is connected to the lower end of the piston rod of the controllable linear motion unit 30. In this embodiment, the fixing adjustment unit 40 includes a clamping structure 41 and a fixing arm 42. One end of the fixing arm 42 is rotatably connected to the lower end of the piston rod of the controllable linear motion unit 30 through a rotating joint 43, and the rotating joint 43 is equipped with a joint limiter 44 for locking its rotation angle. The other end of the fixing arm 42 is connected to the clamping structure 41, which clamps and fixes the probe 60. It should be noted that the connection between the fixing arm 42 and the controllable linear motion unit 30 is the rotating joint 43, which is used to adjust the angle between the clamping structure 41 and the fixing arm 42, thereby adjusting the posture angle of the probe 60 and ensuring that the probe 60 is in a vertical state. After the angle adjustment is completed, the joint limiter 44 is tightened to ensure that the rotating joint 43 no longer rotates, and the probe 60 is stably clamped by the clamping structure 41 and vertically fixed.

[0045] In one example, the rotary joint 43 is a ball joint, consisting of a ball head and a ball socket. The ball socket is located at the lower end of the servo cylinder piston rod, and the ball head is fixed to one end of the fixed arm 42. The ball head and ball socket are engaged by a spherical surface, allowing the fixed arm 42 to be adjusted in multiple directions. The selection criteria for the ball joint are: the ball joint allows for multi-degree-of-freedom angle adjustment, has high adjustment flexibility, and strong load-bearing capacity after locking, which can meet the requirements of the calibration device for the attitude adjustment and angle stability of the probe 60. Secondly, a joint limiter 44 is provided at the connection between the ball joint and the controllable linear motion unit 30. The joint limiter 44 is a screw-locking mechanism, which locks the ball head and ball socket by tightening the bolt to prevent the ball joint from rotating during the descent of the probe 60. The function of the joint limiter 44 is to lock the adjusted angle, bear the reaction force during the descent of the probe 60, and ensure that the angle remains stable. If the joint limiter 44 is a bolt locking mechanism, the clamping force on the ball head can be increased by rotating the bolt, thereby locking the angle of the ball joint.

[0046] In one example, the clamping structure 41 is a common mechanical clamping structure, which fixes the probe 60 to be calibrated. The clamping structure 41 includes a first joint housing and a first inner liner. The first joint housing is formed by the mating of a front arc-shaped clamping piece 411 and a rear arc-shaped clamping piece 412; the first inner liner is formed by the mating of a front arc-shaped gasket 413 and a rear arc-shaped gasket 414. The first inner liner is movably installed inside the first joint housing, and its outer curved surface contour fits against the inner curved surface contour of the first joint housing to achieve radial positioning and relative sliding; the inner curved surface of the first inner liner directly fits against the outer surface of the probe 60 to form a clamping contact surface.

[0047] The front arc-shaped clamp 411 and the rear arc-shaped clamp 412 are respectively provided with horizontally extending mounting planes at both ends. The two mounting planes located on the same side are detachably fixedly connected by a first fastener 415 (e.g., bolt, stud, or screw). By tightening or loosening the first fastener 415, the preload of the first joint housing on the first inner liner can be adjusted, and the installation and removal of the probe 60 can be facilitated.

[0048] To further enhance the clamping stability of the probe 60 and accommodate probes of different diameters or shapes, the clamping structure 41 is also provided with a first locking element 416. Specifically, at least one first locking element 416 is arranged between the front arc-shaped clamp 411 and the front arc-shaped pad 413, and between the rear arc-shaped clamp 412 and the rear arc-shaped pad 414. The first locking element 416 is preferably a bolt locking mechanism, with its bolt shank passing through a threaded hole on the clamp and abutting against the outer curved surface of the corresponding pad. By rotating the bolt (e.g., clockwise), the front arc-shaped pad 413 and / or the rear arc-shaped pad 414 can be pushed radially toward the probe 60, thereby increasing the clamping force of the first liner on the probe 60 independently of the first fastener 415. This design allows the clamping structure 41 to achieve both quick assembly and disassembly and basic clamping through the first fastener 415, and fine adjustment of the clamping force through the first locking element 416, preventing the probe 60 from loosening or shifting. It should be noted that the measuring surface of the probe 60 to be calibrated faces downwards. The function of the clamping structure 41 is to fix the probe 60, so that the probe 60 forms a rigid connection with the piston rod of the servo cylinder. Under the drive of the servo cylinder, the probe 60 moves vertically up and down with the piston rod, ensuring that the position of the probe 60 is stable during the descent and does not shift or shake. Specifically, the first locking member 416 can control the front arc-shaped pad 413 and the rear arc-shaped pad 414 to engage inside the first joint shell formed by the engagement of the front arc-shaped clamping piece 411 and the rear arc-shaped clamping piece 412 to complete the clamping and fixing of the probe 60.

[0049] In one example, the position of the clamping structure 41 relative to the fixed arm 42 can be adjusted horizontally back and forth. The fixed arm 42 has a insertion groove 421 at one end for connecting the clamping structure 41. The insertion groove 421 extends along the length of the fixed arm 42. An insertion rod 417 adapted to the insertion groove 421 is integrally connected to the end of either the front arc-shaped clamping piece 411 or the rear arc-shaped clamping piece 412. The insertion rod 417 is movably inserted into the insertion groove 421 to adjust the horizontal position of the clamping structure 41. The insertion rod 417 and the insertion groove 421 are fixed by a limiting member 418, such as a bolt. The limiting members 418 are symmetrically arranged on the upper and lower sides of the fixed arm 42. The limiting members 418 are threadedly connected to threaded holes on the fixed arm 42, and their ends are pressed against the side of the insertion rod 417, thereby achieving the fixing operation of the insertion rod 417. It should be noted here that the limiting member 418 at the middle position of the fixing arm 42 is loosened to adjust the depth of the insertion rod 417 into the insertion slot 421 so that the probe 60 under test is aligned with the test hole 241 below, and then the limiting member 418 is tightened.

[0050] Please refer to Figure 1 and Figure 4 As shown in this embodiment, it should be noted that the calibration device further includes a horizontal observation sleeve 70, which is fitted onto the probe 60 and is used to indicate the vertical state of the probe 60.

[0051] In one feasible embodiment, the horizontal observation sleeve 70 includes a second joint outer shell and a second inner liner. The second inner liner is movably disposed inside the second joint outer shell, with its outer curved surface fitting against the inner curved surface of the second joint outer shell. The inner curved surface of the second inner liner also fits against the probe 60 surface. The second joint outer shell adopts a split structure, formed by the mating of a first arc-shaped clamp 71 and a second arc-shaped clamp 72. The two ends of the first arc-shaped clamp 71 and the second arc-shaped clamp 72 extend symmetrically outward to form horizontal connecting surfaces. The two opposing horizontal connecting surfaces are detachably fixed by second fasteners 76 (e.g., bolts), thereby achieving radial clamping and basic positioning of the outer shell. The second inner liner also adopts a split structure, formed by the mating of a first arc-shaped gasket 73 and a second arc-shaped gasket 74. The first arc-shaped gasket 73 is movably fitted against the inner side of the first arc-shaped clamp 71, and the second arc-shaped gasket 74 is movably fitted against the inner side of the second arc-shaped clamp 72. This "movable fitting" allows the inner liner to still have a certain adjustment margin after the outer shell is closed. To achieve adjustable clamping of the probe 60, a second locking element 77 is provided between the first arc-shaped clamp 71 and the first arc-shaped pad 73, and between the second arc-shaped clamp 72 and the second arc-shaped pad 74. This second locking element 77 is a bolt-locking mechanism; its bolt passes through the outer shell and abuts against the back of the inner liner. By rotating the bolt (e.g., clockwise), the first arc-shaped pad 73 and / or the second arc-shaped pad 74 can be pushed radially towards the probe 60, thereby independently and progressively increasing the local clamping force on the probe 60. A probe level 75 is provided on the first arc-shaped clamp 71 or the second arc-shaped clamp 72 to indicate the vertical position of the probe 60. It should be noted that before calibration begins, the horizontal observation sleeve 70 is placed on the probe 60 to be measured. The probe 60 is placed vertically on a horizontal platform (such as the bottom surface of the temperature and humidity control box 10 after horizontal adjustment) with the measuring surface facing down. The rotating joint 43 is adjusted to center the bubble of the probe level 75. After adjustment, the second fastener 76 and the second locking member 77 are tightened.

[0052] When the probe 60 is in a vertical position, the bubble in the probe level 75 is centered; when the probe 60 deviates from a vertical position, the bubble in the probe level 75 deviates from the center position, and the direction of deviation indicates the tilt direction. The function of the horizontal observation sleeve 70 is to provide a direct indication of verticality, assisting the operator in adjusting the attitude angle of the probe 60 to ensure that the probe 60 is in a vertical position.

[0053] The implementation principle of this embodiment is as follows: When calibrating the probe 60 using the above-described device, first adjust the level of the temperature and humidity control box 10. The operator rotates the four adjustable support feet 82 while observing the box level 81, adjusting the height of each adjustable support foot 82 until the bubble in the box level 81 is centered. At this point, the temperature and humidity control box 10 is placed horizontally. The purpose of horizontal adjustment is to ensure that the calibration reference surface at the bottom of the temperature and humidity control box 10 is horizontal, providing a reference for the subsequent vertical contact of the probe 60. After the horizontal adjustment is completed, turn on the temperature and humidity controller 11 and set the temperature and humidity to 37°C and the relative humidity to 50%RH. The temperature and humidity controller 11 automatically adjusts the temperature and humidity inside the box according to the set values. The temperature and humidity sensor 12 monitors the temperature and humidity values ​​inside the temperature and humidity control box 10 in real time and feeds them back to the temperature and humidity controller 11, forming a closed-loop control. Wait for the temperature and humidity inside the temperature and humidity control box 10 to reach the set values ​​and remain stable. The temperature is set to 37°C because 37°C is close to the core temperature of human skin, which can simulate the temperature conditions when the probe 60 is actually measuring. The relative humidity is set to 50%RH because 50%RH is the typical humidity environment for human skin, which can simulate the humidity conditions under which the probe 60 is actually measured.

[0054] Weigh a fixed mass of sodium polyacrylate and place it in a container. Add a fixed proportion of deionized water and mix well to prepare a 0.1%~0.5% (m / v) sodium polyacrylate solution. Pipette 2 mL of the 0.1%~0.5% sodium polyacrylate solution (m / v) and add it dropwise onto a sponge sheet with a thickness of 5 mm, a diameter of 3 cm, and a hardness of 25D~35D. The sponge sheet absorbs the solution, thus obtaining a sodium polyacrylate aqueous solution sponge disc (the concentration, amount of sodium polyacrylate solution, and the size of the sponge sheet can be adjusted appropriately). Place the prepared sodium polyacrylate aqueous solution sponge disc into the cylindrical groove 231 of the lower base 23. Then, cover the upper base 23 with a waterproof and breathable membrane 22. The waterproof and breathable membrane 22 can be medical grade or high-end industrial grade. Finally, align the upper cover 24 with the threads of the lower base 23 and tighten it to fix the waterproof and breathable membrane 22 and the sodium polyacrylate aqueous solution sponge disc, creating a stable and uniform "simulated skin" interface. The water vapor transmission rate of the waterproof and breathable membrane 22 is set at 8-22 g / m². 2 The basis for ·h is that this range is close to the actual water vapor permeability of the stratum corneum of human skin, which can simulate the permeability characteristics of the stratum corneum and establish a vapor pressure gradient that conforms to physiology.

[0055] A horizontal observation sleeve 70 is fitted over the upper end of the probe 60. The upper end of the probe 60 is wrapped with a first arc-shaped pad 73 and a second arc-shaped pad 74, and then clamped by a first arc-shaped clamp 71 and a second arc-shaped clamp 72, forming a ball joint. The two ends of the first arc-shaped clamp 71 and the second arc-shaped clamp 72 are fixed with a second fastener 76, which is then slightly tightened. The probe 60 to be tested is placed vertically on a horizontal platform (such as the bottom surface of the temperature and humidity control box 10 after leveling). The rotating joint 43 is adjusted to center the bubble of the probe level 75 on the horizontal observation sleeve 70. After adjustment, the second locking piece 77 and the second fastener 76 are tightened, and the horizontal observation sleeve 70 is now installed and adjusted. Before subsequent calibration operations are completed, all second locking pieces 77 and second fasteners 76 on the horizontal observation sleeve 70 will not be moved.

[0056] The lower end of the probe 60 is held by the clamping structure 41 of the fixing arm 42. The lower end of the probe 60 is wrapped with a front arc-shaped pad 413 and a rear arc-shaped pad 414, and then clamped by a front arc-shaped clamp 411 and a rear arc-shaped clamp 412, forming a ball joint. The first fasteners 415 at both ends of the front arc-shaped clamp 411 and the rear arc-shaped clamp 412 are slightly tightened. The plug rod 417 is adjusted to a suitable length so that the bottom test surface of the probe 60 is directly facing the test hole 241 below. The limiting piece 418 on the fixing arm 42 is initially tightened. By adjusting the ball joint formed by the front arc-shaped clamp 411, the rear arc-shaped clamp 412, the front arc-shaped pad 413, and the rear arc-shaped pad 414, and simultaneously adjusting the rotating joint 43, the bubble of the probe level 75 on the horizontal observation sleeve 70 installed at the upper end of the probe 60 is centered. If necessary, the first fastener 415 can be loosened for adjustment. After the test angle and the length of the connector 417 are adjusted, tighten the first fastener 415, the first locking member 416, the limiting member 418, and the joint limiter 44. The probe 60 is then clamped at the required angle, ensuring that the vertical posture of the probe 60 remains unchanged during the subsequent descent. The purpose of adjusting the posture of the probe 60 is to ensure that the probe 60 contacts the waterproof and breathable membrane 22 below in a vertical posture, avoiding measurement errors caused by uneven contact due to posture tilt.

[0057] The descent pressure of the servo cylinder is set to the standard measurement pressure of probe 60. After waiting for the internal temperature and humidity of the temperature and humidity control box 10 to reach the preset value and stabilize for a certain period of time, the controllable linear motion unit 30 is controlled to descend vertically. The piston rod of the servo cylinder drives the fixed adjustment unit 40 and probe 60 to descend vertically. When the measuring surface of probe 60 contacts the waterproof and breathable membrane 22, the precision pressure controller detects the increase in resistance through the force sensor built into the servo cylinder. When the resistance rises to the set standard measurement pressure, the precision pressure controller controls the servo cylinder to stop increasing the downward force and maintain the existing pressure, so that probe 60 and waterproof and breathable membrane 22 maintain stable contact. The stability of the contact pressure is achieved through the force feedback control of the servo cylinder. The force sensor monitors the contact pressure value in real time. When the pressure deviates from the set value, the servo cylinder automatically adjusts the output force to bring the pressure back to the set value. After probe 60 contacts waterproof and breathable membrane 22 and maintains stable pressure, probe 60 begins to read the measurement value.

[0058] For the capacitive skin moisture content probe, probe 60 measures the capacitance value at the interface between the waterproof and breathable membrane 22 and the biomimetic material layer 21, which reflects the moisture content of the interface. For the vapor pressure gradient transdermal water loss probe, probe 60 measures the water vapor pressure gradient on the surface of the waterproof and breathable membrane 22, which reflects the rate of evaporation of moisture through the membrane. After probe 60 completes its reading, a precision pressure controller controls the controllable linear motion unit 30 to rise, and the piston rod of the servo electric cylinder drives the fixed adjustment unit 40 and probe 60 to rise vertically to the initial position, completing one calibration reading.

[0059] By adopting the above technical solution, this application achieves the following technical effects. First, the temperature and humidity control chamber 10 provides a constant temperature and humidity environment (37℃, 50%RH), simulating the physiological conditions of human skin, thus unifying the calibration conditions with the actual measurement conditions and eliminating systematic errors introduced by environmental mismatch. Second, the "simulated skin" interface constructed by the biomimetic material layer 21 and the waterproof and breathable membrane 22 simultaneously meets the calibration requirements of both the capacitance method probe and the vapor pressure gradient method probe. The biomimetic material layer 21 provides a stable moisture source for capacitance measurement calibration of the capacitance method probe; the waterproof and breathable membrane 22 establishes a physiologically consistent vapor pressure gradient for water loss rate measurement calibration of the vapor pressure gradient method probe. Third, the temperature and humidity control box 10 is leveled using the box level 81 and adjustable support feet 82, while the probe 60 is vertically adjusted using the rotating joint 43 and horizontal observation sleeve 70. Precise control and feedback adjustment of the contact pressure are achieved through a servo electric cylinder and a precision pressure controller. This standardizes the two key variables—the probe 60 placement angle and the contact pressure—fundamentally eliminating random errors introduced by different operator techniques and greatly improving the repeatability and reproducibility of calibration results. Fourth, the calibration benchmark of this device is defined by precisely controllable and quantifiable physical parameters (temperature 37℃, relative humidity 50%RH). These parameters are directly traceable to national or international metrological standards, providing testing institutions with independent and reliable traceability, solving the problem of dependence on manufacturer calibration parts, and enabling third-party testing institutions to issue credible calibration reports.

[0060] Example 2 This embodiment provides a method for calibrating a skin moisture parameter testing probe using the above-described calibration device, comprising the following steps: Step 1: Adjust the calibration area of ​​the temperature and humidity control box 10 to the preset temperature and humidity conditions and keep it stable. The preset temperature and humidity conditions are 37°C and 50%RH. Step 2: Adjust the orientation of the probe 60 to make it vertical and keep it fixed, including: adjusting the rotating joint 43, observing the probe level 75 set on the horizontal observation sleeve 70, and after the bubble of the probe level 75 is centered, tighten the joint limiter 44 to lock the rotating joint 43 so that the probe 60 remains vertical.

[0061] Step 3: Prepare a biomimetic material layer 21 with defined water absorption properties; including: weighing a fixed mass of sodium polyacrylate, placing it in a container, adding a fixed proportion of deionized water and mixing well to prepare a 0.1%~0.5% (m / v) sodium polyacrylate solution. Pipette 2 mL of the 0.1%~0.5% sodium polyacrylate solution (m / v) and add it dropwise onto a sponge sheet with a thickness of 5 mm, a diameter of 3 cm, and a hardness of 25D~35D, allowing it to be absorbed by the sponge, thus obtaining a sodium polyacrylate aqueous solution sponge sheet.

[0062] Step 4: Assemble the biomimetic material layer 21 and the waterproof and breathable membrane 22 to form a calibration reference interface; Step 5: Under stable environmental conditions, control probe 60 to contact the calibration reference interface with a preset pressure, wherein the preset pressure is the standard measurement pressure of probe 60; Step 6: Maintain contact pressure until the measurement is complete, then release the contact.

[0063] It is understood that this application has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this application. Furthermore, based on the teachings of this application, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this application. Therefore, this application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this application.

Claims

1. A calibration device, characterized in that, The probe (60) used for calibrating skin moisture parameter testing includes: Temperature and humidity control box (10) is used to maintain the calibration area at preset temperature and humidity conditions; The calibration unit (20), located inside the temperature and humidity control box (10), includes a biomimetic material layer (21) and a waterproof and breathable membrane (22). The biomimetic material layer (21) is used to provide a stable moisture reference, and the waterproof and breathable membrane (22) covers the biomimetic material layer (21) to form a calibration reference interface and is used to establish a stable water vapor pressure gradient. A controllable linear motion unit (30) is installed inside the temperature and humidity control box (10) and can drive the probe (60) to move in the vertical direction; A fixed adjustment unit (40) is connected to the controllable linear motion unit (30) for fixing the probe (60) and for adjusting the attitude angle of the probe (60); The pressure control unit (50) is used to control the contact pressure between the probe (60) and the calibration reference interface of the calibration unit (20).

2. The calibration device according to claim 1, characterized in that, The calibration unit (20) further includes: The lower base (23) is located at the bottom of the temperature and humidity control box (10), and a groove (231) is opened on its top, and the biomimetic material layer (21) is accommodated in the groove (231); The upper cover (24) is disposed on the lower base (23) and is used to press and fix the waterproof and breathable membrane (22) onto the biomimetic material layer (21). The top of the upper cover (24) is provided with a test hole (241) for the probe (60) to contact the waterproof and breathable membrane (22).

3. The calibration device according to claim 1 or 2, characterized in that, The biomimetic material layer (21) is a sponge sheet containing sodium polyacrylate solution; The water vapor transmission rate of the waterproof and breathable membrane (22) is 8-22 g / m. 2 Within the range of h.

4. The calibration device according to claim 1, characterized in that, The fixed adjustment unit (40) includes a clamping structure (41) and a fixing arm (42); One end of the fixing arm (42) is connected to the clamping structure (41), which is used to clamp and fix the probe (60); The other end of the fixed arm (42) is provided with a rotating joint (43), and is rotatably connected to the controllable linear motion unit (30) through the rotating joint (43); The rotating joint (43) is equipped with a joint limiter (44) for locking its rotation angle.

5. The calibration device according to claim 4, characterized in that, The clamping structure (41) includes: a first joint shell formed by the mating of a front arc-shaped clamping piece (411) and a rear arc-shaped clamping piece (412), and a first inner liner formed by the mating of a front arc-shaped pad (413) and a rear arc-shaped pad (414); The first liner is disposed inside the first joint housing, and the outer curved surface of the first liner is in contact with the inner curved surface of the first joint housing, and the inner curved surface of the first liner is in contact with the surface of the probe (60). The front arc-shaped clip (411) and the rear arc-shaped clip (412) are detachably fixed together by a first fastener (415); A first locking member (416) is provided between the front arc-shaped clamp (411) and the front arc-shaped gasket (413), and between the rear arc-shaped clamp (412) and the rear arc-shaped gasket (414).

6. The calibration apparatus according to claim 5, characterized in that, The fixed arm (42) is provided with a plug groove (421) at one end for connecting to the clamping structure (41); The end of the front arc-shaped clip (411) or the rear arc-shaped clip (412) is connected to a plug rod (417) that is adapted to the plug groove (421); The insertion depth of the plug rod (417) into the plug groove (421) is used to adjust the horizontal position of the clamping structure (41); The plug rod (417) and the plug slot (421) are fixed by a limiting member (418).

7. The calibration apparatus according to claim 1, characterized in that, The calibration device also includes: A horizontal observation sleeve (70) is fitted onto the probe (60) to indicate the vertical state of the probe (60); And / or, A horizontal adjustment unit (80) is installed on the temperature and humidity control box (10) for adjusting the horizontal state of the temperature and humidity control box (10).

8. The calibration apparatus according to claim 7, characterized in that, The horizontal observation sleeve (70) includes: a second joint shell formed by the mating of a first arc-shaped clip (71) and a second arc-shaped clip (72); a second inner liner formed by the mating of a first arc-shaped pad (73) and a second arc-shaped pad (74); and a probe level (75) disposed on the first arc-shaped clip (71) or the second arc-shaped clip (72) and used to indicate the vertical state of the probe (60); The second liner is disposed inside the second joint housing, and the outer curved surface of the second liner is in contact with the inner curved surface of the second joint housing, and the inner curved surface of the second liner is in contact with the surface of the probe (60). The first arc-shaped clip (71) and the second arc-shaped clip (72) are detachably fixed together by a second fastener (76); A second locking member (77) is provided between the first arc-shaped clamp (71) and the first arc-shaped gasket (73), and between the second arc-shaped clamp (72) and the second arc-shaped gasket (74).

9. The calibration apparatus according to claim 7, characterized in that, The horizontal adjustment unit (80) includes: A box level (81) is installed at the bottom inside the temperature and humidity control box (10) to indicate the horizontal state of the temperature and humidity control box (10); Adjustable support feet (82) are provided on the outer bottom of the temperature and humidity control box (10) and are used to adjust the height of the temperature and humidity control box (10) according to the box level (81) so that it is in a horizontal state.

10. A method for calibrating a skin moisture parameter testing probe (60) using the calibration device as described in any one of claims 1 to 9, characterized in that, Includes the following steps: The calibration area of ​​the temperature and humidity control box (10) is adjusted to the preset temperature and humidity conditions and kept stable, wherein the preset temperature and humidity conditions are a temperature of 37°C and a relative humidity of 50%RH; Adjust the orientation of the probe (60) to make it vertical and keep it fixed; Prepare a biomimetic material layer with defined water absorption properties (21); The biomimetic material layer (21) and the waterproof and breathable membrane (22) are assembled to form a calibration reference interface; Under stable environmental conditions, the probe (60) is controlled to contact the calibration reference interface at a preset pressure, wherein the preset pressure is the standard measurement pressure of the probe; Maintain contact pressure until the measurement is complete, then release the contact.

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