A time-domain near-infrared depth detection device

Abstract

The utility model relates to time domain near infrared detection standardization verification and dummy test technical field, concretely is a kind of time domain near infrared depth detection device.The device includes mounting plate, the U-shaped support of mounting plate upper end and the optical box of mounting plate lower end.The center through-hole is equipped in the center of mounting plate, and a plurality of mounting protrusions are arranged along the circumferential interval of center through-hole, and a plurality of optical assemblies are equipped on mounting protrusion.U-shaped support is equipped with electric control displacement device, and the upper end of electric control displacement device is equipped with control transmission circuit.Optical box is equipped with layered optical module and movable target layer controlled by electric control displacement device.The utility model drives movable target layer to step along the depth direction in layered optical module by electric control displacement device, cooperates fixed optical fiber assembly, can establish stable "target depth-time domain signal" response relationship, realizes the automation, standardization verification of system depth resolution performance, effectively improves test precision, repeatability and detection efficiency.

Description

Technical Field

[0001] This utility model relates to the field of time-domain near-infrared detection standardization verification and phantom testing technology, and in particular to a time-domain near-infrared depth detection device. Background Technology

[0002] TD-fNIRS (Time-Domain Functional Near-Infrared Spectroscopy) systems have greater depth resolution potential compared to continuous-wave near-infrared technology, and their system performance typically requires verification using phantoms or layered phantoms. Current verification methods often employ a fixed-thickness, uniformly sized phantom with manual insertion of the absorbing target, or manual adjustment of the target layer position through manual raising and lowering or inserting of phantoms, followed by observation of response changes at different depths. While these methods can simulate the tissue scattering environment to some extent, they still suffer from two prominent problems: First, target layer depth adjustment relies on manual operation, resulting in insufficient step accuracy and repeatability, making it difficult to achieve continuous and precise depth scanning; second, the geometric relationship between the target layer, the phantom, and the transmitting / receiving fibers often requires repeated clamping and manual alignment, which can easily introduce additional errors due to different assembly conditions, making it difficult to establish a stable "target depth - detection result" correspondence. The closest technical solution to this application is a detection structure that uses a layered phantom body with manual slide rails or mechanical clamps to adjust the target position. However, this type of solution usually lacks an upper electrically controlled displacement mechanism, a vertical drive component directly connected to the target layer, a lower fixed fiber optic assembly, and a linkage design between the control unit / data interface, which corresponds to the structure shown in the attached figure. This makes it difficult to efficiently support standardized comparative tests between different time gate widths, different time windows, and different inversion models. These shortcomings directly lead to low depth calibration efficiency, large result dispersion, and difficulty in cross-system benchmarking, which is detrimental to the research, development, verification, and standardized evaluation of time-domain near-infrared devices. Utility Model Content

[0003] The purpose of this invention is to solve the problems of insufficient target layer positioning accuracy, poor depth step repeatability, unstable geometric relationship between fiber optic components and target layer, and difficulty in automating the testing process in existing phantom verification methods. In order to output detection signals at different target depths in a standardized and repeatable manner, it can be used to verify the depth selectivity, time gating settings, and DOT inversion model performance of the TD-fNIRS system.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] A time-domain near-infrared depth detection device includes a mounting plate, a U-shaped bracket disposed at the upper end of the mounting plate, and an optical housing disposed at the lower end of the mounting plate. The mounting plate has a central through-hole, and multiple mounting protrusions are spaced circumferentially along the central through-hole, each protruding with a plurality of optical components. An electrically controlled displacement device is mounted on the U-shaped bracket, and a control transmission line is located at the upper end of the electrically controlled displacement device. The optical housing contains layered optical modules and a movable target layer controlled by the electrically controlled displacement device. This device improves the accuracy and stability of phantom testing and signal collection through fixed spacing and electrically controlled lifting techniques.

[0006] Preferably, the electrically controlled displacement device has mounting ears with through holes on both sides, and the U-shaped bracket has mounting holes that mate with the mounting ears. The mounting holes are used to insert bolts to fix the electrically controlled displacement device.

[0007] Preferably, multiple corner plates are provided at the connection between the mounting plate and the U-shaped bracket. The corner plates are located at the corners where the mounting plate and the U-shaped bracket connect to improve the overall structural stability of the device.

[0008] Preferably, the lower end of the electrically controlled displacement device is provided with a connecting shaft, and the movable target layer is connected to the electrically controlled displacement device through the connecting shaft. The connecting shaft is used to generate a traction effect on the movable target layer.

[0009] Preferably, the control transmission line is connected to a control detection device, which is used to control the depth position of the movable target layer and synchronously bind and store the time-domain signals collected by the optical components.

[0010] Preferably, the optical components include fiber optic components and a light-shielding cap.

[0011] Preferably, the optical fiber assembly includes a transmitting optical fiber assembly and a receiving optical fiber assembly. The transmitting optical fiber assembly and the receiving optical fiber assembly are used to transmit and receive light to the layered optical module, respectively, and the light-shielding cap is used to prevent ambient light from entering.

[0012] Preferably, the transmitting fiber optic assembly, the receiving fiber optic assembly, and the light-shielding caps are spaced apart on the mounting protrusions. The transmitting and receiving fiber optic assemblies are mounted symmetrically on the mounting protrusions to form a detection optical path, while the remaining mounting protrusions are fitted with light-shielding caps to prevent external light from flowing in.

[0013] Compared with existing technologies, the advantages of this utility model are as follows: 1. By setting an electrically controlled displacement mechanism located on the upper part of the phantom body and directly connecting it to the movable target layer, the accuracy, repeatability, and testing efficiency of the target layer depth adjustment can be significantly improved; 2. By integrating the layered optical module, the movable target layer, and the lower fixed fiber optic assembly into the same phantom body, the transmit / receive geometry can be kept stable, reducing errors caused by repeated clamping; 3. By synchronously recording the depth position and acquired data through the control unit, a standard correspondence between "target depth - time window response - inversion result" can be established, providing benchmark data for time gating parameter optimization and DOT model verification; 4. By linking with an external host through a data interface, an automated and batch standard testing process can be formed, facilitating R&D benchmarking, factory quality inspection, and third-party performance verification; 5. The device has a clear structure and well-defined objectives, which helps to improve the standardization and traceability of the TD-fNIRS system depth performance verification. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a time-domain near-infrared depth detection device of the present invention from the first angle;

[0015] Figure 2 This is a structural schematic diagram of the present invention from a second angle;

[0016] Figure 3 This is a front view of the present invention.

[0017] The components include: 1. Mounting plate; 11. Mounting protrusion; 12. Central through hole; 2. U-shaped bracket; 21. Corner plate; 22. Mounting hole; 3. Optical housing; 31. Layered optical module; 4. Electrically controlled displacement device; 5. Control transmission line; 6. Fiber optic assembly; 61. Transmitting fiber optic assembly; 62. Receiving fiber optic assembly; 7. Light-shielding cap; 8. Connecting shaft; 9. Movable target layer. Detailed Implementation

[0018] To enable those skilled in the art to clearly and completely understand the technical solution of this utility model, the following detailed description is provided in conjunction with embodiments. Obviously, the embodiments described herein are only for explaining this utility model and are not intended to limit the scope of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this utility model.

[0019] In the description of this utility model, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] Example 1: As Figures 1-3 As shown, a time-domain near-infrared depth detection device includes a mounting plate 1, a U-shaped bracket 2 disposed at the upper end of the mounting plate 1, and an optical housing 3 disposed at the lower end of the mounting plate 1. The mounting plate 1 has a central through hole 12, and multiple mounting protrusions 11 are arranged at intervals around the central through hole 12. Multiple optical components are disposed on the mounting protrusions 11. An electrically controlled displacement device 4 is disposed on the U-shaped bracket 2, and a control transmission line 5 is disposed at the upper end of the electrically controlled displacement device 4. The optical housing 3 contains a layered optical module 31 and a movable target layer 9 controlled by the electrically controlled displacement device 4.

[0021] In this embodiment, the mounting plate 1 is generally flat, with a central through hole 12. Multiple mounting protrusions 11 are spaced circumferentially along the central through hole 12, and an optical component is fixed to each mounting protrusion 11. More specifically, each pair of opposite mounting protrusions 11 is grouped together; in this embodiment, there are four mounting protrusions 11, i.e., two groups of mounting protrusions: a working protrusion group and a light-shielding protrusion group. The spacing of the mounting protrusions 11 is detailed in Table 1.

[0022] Table 1: Spacing Settings for Mounting Protrusion 11

[0023] The U-shaped bracket 2 is fixedly mounted on the upper end of the mounting plate 1, forming an inverted "U"-shaped frame structure. The U-shaped bracket 2 is bolted to the mounting plate 1. The electrically controlled displacement device 4 is fixedly mounted on the upper crossbeam of the U-shaped bracket 2, with its output end extending vertically downwards. In this embodiment, the electrically controlled displacement device 4 uses an IP60-24V-50mm-5S-Y type Pfide mini push rod. The upper end of the electrically controlled displacement device 4 is equipped with a control transmission line 5, which can serve as both a power line and a data transmission line. The control transmission line 5 is connected to a control detection device to receive displacement commands and provide feedback on position information. The optical housing 3 adopts a black housing structure and is fixed to the lower end of the mounting plate 1 by bolts to prevent external light sources from affecting accuracy. The layered optical module 31 is composed of multiple layers of phantom media stacked along the depth direction, used to simulate the optical environment of different tissue layers. In this embodiment, the layered optical module 31 uses a liquid phantom and is set as a double-layer model to simulate superficial tissues (such as scalp / skull) and deep brain tissue, respectively. (1) Liquid phantoms: suitable for simulating dynamic physiological processes, such as changes in blood flow and oxygenation. Liquid phantoms mainly use physiological saline as a common material. Some studies use saline layers of different concentrations and thicknesses to simulate the electrical properties of scalp and brain tissue. The core advantage of liquid phantoms is that they can simulate dynamic changes and are difficult to construct multi-layer structures; (2) Blood-lipid mixture: an ideal material for simulating dynamic changes. The oxygenation state of the phantom can be independently controlled by consuming oxygen through chemical reactions or by introducing oxygen; (3) Ink + fat emulsion solution: ink is used as an absorbent and fat emulsion solution is used as a scattering agent. The optical parameters can be changed by adjusting the concentration of the two. The layered optical module 31 has a movable target layer 9 inside, which is driven by an electrically controlled displacement device 4 to move back and forth along the depth direction inside the layered optical module 31. The specific model of the movable target layer 9 is Glass10, which is a transparent glass ball with a diameter of 10mm, filled with black ink and sealed with a silicone plug. In use, this device emits light pulses to the layered optical module 31 via optical components. The movable target layer 9 interacts with the light signal at different depths, changing the photon time-of-flight distribution. The diffusely reflected light carrying depth information is collected by the optical components and transmitted back to the device for analysis. Since the position of the optical components is fixed, while the depth of the target layer is precisely controlled by the electronically controlled displacement device 4, a stable "depth-signal" correspondence can be established, enabling automated verification of the system's depth resolution performance.

[0024] Furthermore, the electric displacement device 4 is provided with mounting ears with through holes on both sides, and the U-shaped bracket 2 is provided with mounting holes 22 that cooperate with the mounting ears.

[0025] The electrically controlled displacement device 4 has mounting ears on both sides, each with through holes. Correspondingly, the upper crossbeam of the U-shaped bracket 2 has mounting holes 22 on both sides, each corresponding to one of the through holes. During assembly, the electrically controlled displacement device 4 is placed above the crossbeam of the U-shaped bracket 2, aligning the through holes on the mounting ears with the mounting holes 22. Screws or bolts are then passed through the through holes and screwed into the mounting holes 22 to reliably fix the electrically controlled displacement device 4 onto the U-shaped bracket 2. This connection method not only facilitates assembly and disassembly and provides accurate positioning, but also ensures that the output shaft of the electrically controlled displacement device 4 remains coaxial with the central through hole 12 of the mounting plate 1, thereby ensuring the vertical movement accuracy and stability of the movable target layer 9.

[0026] Furthermore, multiple corner plates 21 are provided at the connection between the mounting plate 1 and the U-shaped bracket 2.

[0027] The corner plates 21 are triangular or L-shaped plate structures, installed at the connection between the vertical section of the U-shaped bracket 2 and the mounting plate 1 by screws or welding. Multiple corner plates 21 are symmetrically distributed to distribute the force evenly. The reinforcement connection using corner plates 21 can significantly improve the connection stiffness and bending strength between the U-shaped bracket 2 and the mounting plate 1, ensuring the verticality of the electrically controlled displacement device 4 and the motion accuracy of its driven movable target layer 9, further improving the stability and repeatability of the detection results.

[0028] Furthermore, the lower end of the electrically controlled displacement device 4 is provided with a connecting shaft 8, and the movable target layer 9 is connected to the electrically controlled displacement device 4 through the connecting shaft 8.

[0029] In this embodiment, the connecting shaft 8 is a 0.5mm diameter linear optical shaft made of bearing steel. Its upper end is fixed to the moving end of the electrically controlled displacement device 4, and its lower end passes through the central through hole 12 in the center of the mounting plate 1 and is fixed to the top connection point of the movable target layer 9. When the electrically controlled displacement device 4 receives a control command to extend or retract, its output end drives the movable target layer 9 to move synchronously up and down in the vertical direction within the layered optical module 31 via the connecting shaft 8, thereby accurately changing the depth position of the target layer in the phantom. Using the connecting shaft 8 as a transmission component results in a simple structure, light weight, and low resistance to the movement of the target layer, which is beneficial for improving the accuracy of depth positioning and the stability of movement.

[0030] Furthermore, the control transmission line 5 is connected to a control detection device, which is used to control the depth position of the movable target layer 9 and synchronously bind and store the time-domain signals collected by the optical components.

[0031] In this embodiment, the electrically controlled displacement device 4, the control transmission line 5, and the control detection device constitute an embedded system integrating power management, motor drive, user interaction, and data communication. Its core working principle can be summarized as follows: using an MCU (microcontroller unit) as the brain, it obtains power and data through a Type-C interface, precisely drives the motor based on button input and preset programs, and provides real-time status feedback on the display screen. The Type-C interface plays a dual role in power supply and data transmission; the standard Type-C interface provides 5V by default. If the driver board requires higher power, higher voltages (such as 9V, 12V, 15V, 20V) can be negotiated through protocols. The control detection device communicates with a host computer or other computer via USB data through the D+ and D- pins of the Type-C interface. The buttons and display screen on the control detection device constitute the most direct human-machine interface (HMI). Buttons are typically connected in a "pull-down" manner. When a button is pressed, the corresponding pin of the MCU detects a low level, triggering the corresponding action. The display screen provides real-time feedback on the push rod status, such as current position, speed, and operating mode. To reduce power consumption, low-power screens such as OLEDs are usually selected, and automatic screen-off functionality is supported.

[0032] Furthermore, the optical components include fiber optic assembly 6 and light-shielding cap 7.

[0033] The light-shielding cap 7 is a cap-shaped or plug-shaped structure made of opaque material, and its size is adapted to the mounting protrusion 11. It is used to seal the mounting hole at the mounting protrusion 11 where the fiber optic assembly 6 is not installed. The light-shielding cap 7 and its corresponding mounting protrusion 11 form a light-shielding protrusion group, and the fiber optic assembly 6 and its corresponding mounting protrusion 11 form a working protrusion group. The fiber optic assembly 6 and the light-shielding cap 7 are respectively fixed on the corresponding mounting protrusion 11. The two work together to ensure the normal transmission of the optical signal required for detection, and effectively block stray light from the external environment from entering the optical housing 3 through the unused mounting hole, avoiding interference with the diffuse reflection signal, thereby improving the detection signal-to-noise ratio and the accuracy of the measurement results.

[0034] Furthermore, the optical fiber assembly 6 includes a transmitting optical fiber assembly 61 and a receiving optical fiber assembly 62.

[0035] One end of the transmitting fiber assembly 61 is equipped with an SMA905 fiber optic connector for connecting to the transmitting port of an external time-domain near-infrared device, and the other end is fixed to a corresponding mounting protrusion 11. This allows the ultrafast light pulses generated by the external device to be guided into the layered optical module 31 inside the optical housing 3. One end of the receiving fiber assembly 62 is fixed to the corresponding mounting protrusion 11, and the other end is equipped with an SMA905 fiber optic connector for connecting to the receiving port of an external time-domain near-infrared device. This allows the receiving fiber assembly 62 to collect diffusely reflected light signals carrying depth information of the movable target layer 9 after being scattered by the layered optical module 31, and transmit these signals back to the external device for time-point spread function (TPSF) analysis. By setting up independent transmitting fiber optic assemblies 61 and 62, the physical separation of the optical signal transmission and reception channels is achieved. This facilitates flexible adjustment of the relative positions of the transmitting and receiving fibers according to different detection requirements, and also facilitates independent maintenance and replacement of the fibers.

[0036] Furthermore, the transmitting fiber assembly 61, the receiving fiber assembly 62, and the light-shielding cap 7 are spaced apart on the mounting protrusion 11.

[0037] More specifically, the transmitting fiber assembly 61 is fixed to one of the mounting protrusions 11, and the receiving fiber assembly 62 is fixed to a mounting protrusion 11 symmetrical to the transmitting fiber assembly 61. Light-shielding caps 7 made of black silicone are installed on the remaining mounting protrusions 11 where no fiber optic assemblies are installed. By employing an alternating layout of the transmitting fiber assembly 61, the receiving fiber assembly 62, and the light-shielding caps 7, a suitable source-detector spacing is ensured between the transmitting and receiving fibers, meeting the geometric conditions for time-domain near-infrared detection signal acquisition. Furthermore, the light-shielding caps 7 completely block the unused mounting protrusions 11, preventing stray ambient light from entering the optical housing 3 from the side and interfering with the detection signal. This alternating layout is simple and compact, facilitating rapid installation and removal of the fibers, while ensuring that the optical components do not interfere with each other in multi-channel detection scenarios, effectively improving the stability and reliability of the detection signal.

[0038] Based on the above embodiment 1, embodiment 2 of the working mode of this device is provided:

[0039] Phase 1: System preparation and parameter configuration.

[0040] A1. Insert the transmitting fiber assembly 61 and the receiving fiber assembly 62 into the mounting protrusion 11 with a fixed center distance of 30mm and fix them to ensure good coupling of the optical path on the surface of the layered optical module 31.

[0041] A2. Power on the device and use the MCU inside the control detection device connected by the control transmission line 5 to perform a self-test and confirm the initial position of the electric displacement device 4 and the movable target layer 9 (usually located at the midpoint of the stroke or the shallowest point).

[0042] A3. Setting the scanning task through the control detection device requires configuring the following:

[0043] (1) Scanning range: Using the 50mm stroke of the push rod, combined with the phantom layer structure, the lifting start and stop depth of the movable target layer 9 is set;

[0044] (2) Step interval: Sets the distance between each movement that determines the depth resolution;

[0045] (3) Sampling integration time: Set the time for the time-domain device to collect signals at each depth position to ensure that a sufficient signal-to-noise ratio is obtained.

[0046] Phase 2: Automated depth scan cycle.

[0047] B1. The MCU drives the electronically controlled displacement device 4 to precisely push the movable target layer 9 at its lower end to the preset starting depth position.

[0048] B2. The MCU sends a synchronization trigger signal to the time-domain near-infrared device through the control transmission line 5. The device then sends a series of ultrafast (picosecond-level) light pulses to the layered optical module 31 through the transmitting fiber optic component 61.

[0049] B3. The light pulse enters the layered optical module 31, which is designed to simulate the optical properties of different layers of the brain, such as the scalp, skull, cerebrospinal fluid, and gray matter. A portion of the diffused photons propagate to the depth of the movable target layer 9. Because the black ink within the movable target layer 9 has an extremely high absorption coefficient, it forms a strong optical contrast with the surrounding background of the layered optical module 31. After the photons interact with the movable target layer 9, their time-of-flight distribution (time-point spread function, TPSF) changes significantly, and the attenuation mode is directly related to the depth of the target sphere.

[0050] B4. Diffuse reflected light carrying target depth information is collected by receiving fiber optic component 62 and transmitted back to the time domain device, which records the TPSF curve at this time.

[0051] B5. The MCU binds and stores the current movable target layer 9 depth position and the corresponding time domain signal data;

[0052] B6. The MCU drives the electronically controlled displacement device 4 according to the preset step size to move the target ball up or down to the next depth position.

[0053] B7. Repeat steps B2 to B6 above until all the set scan strokes are completed.

[0054] Phase 3: Data processing and result output.

[0055] C1. After the scan is completed, the MCU integrates all the "Depth-TPSF" datasets and performs preprocessing such as denoising and averaging on the original time domain signal.

[0056] C2. Perform quantitative analysis on the time-domain signal at each depth point, for example:

[0057] (1) Observe the attenuation curve of the total area (representing the total light intensity) under the TPSF curve as the depth of the movable target layer 9 changes;

[0058] (2) Extract parameters that are highly sensitive to the depth and location of the target, such as average flight time and peak time.

[0059] C3. Generate a "signal feature-depth" calibration curve and display it on the screen;

[0060] C4. Export all raw data and calibration curves through the data interface for further in-depth analysis or as a basis for instrument calibration.

[0061] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A time-domain near-infrared depth detection device, characterized in that, The device includes a mounting plate, a U-shaped bracket disposed at the upper end of the mounting plate, and an optical housing disposed at the lower end of the mounting plate. The mounting plate has a central through hole, and multiple mounting protrusions are spaced apart circumferentially along the central through hole. Multiple optical components are disposed on the mounting protrusions. An electrically controlled displacement device is disposed on the U-shaped bracket, and a control transmission line is disposed at the upper end of the electrically controlled displacement device. The optical housing contains a layered optical module and a movable target layer controlled by the electrically controlled displacement device.

2. The time-domain near-infrared depth detection device according to claim 1, characterized in that, The electrically controlled displacement device has mounting ears with through holes on both sides, and the U-shaped bracket has mounting holes that mate with the mounting ears.

3. The time-domain near-infrared depth detection device according to claim 1, characterized in that, The mounting plate and the U-shaped bracket are provided with multiple corner plates at the connection point.

4. The time-domain near-infrared depth detection device according to claim 1, characterized in that, The lower end of the electrically controlled displacement device is provided with a connecting shaft, and the movable target layer is connected to the electrically controlled displacement device through the connecting shaft.

5. The time-domain near-infrared depth detection device according to claim 1, characterized in that, The control transmission line is connected to a control detection device, which is used to control the depth position of the movable target layer and synchronously bind and store the time-domain signals collected by the optical components.

6. The time-domain near-infrared depth detection device according to claim 1, characterized in that, The optical components include fiber optic components and a light-shielding cap.

7. The time-domain near-infrared depth detection device according to claim 6, characterized in that, The optical fiber assembly includes a transmitting optical fiber assembly and a receiving optical fiber assembly.

8. The time-domain near-infrared depth detection device according to claim 7, characterized in that, The transmitting fiber assembly, the receiving fiber assembly, and the light-shielding cap are spaced apart on the mounting protrusion.

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