Optical fiber cable and near-infrared brain function imaging system with same

Abstract

The embodiment of the utility model provides an optical fiber cable and a near-infrared brain function imaging system with the same, the optical fiber cable comprises an optical fiber, a fabric layer and an outer sleeve layer, the fabric layer sleeves the optical fiber, and on at least a middle section of the optical fiber cable, the fabric layer can slide relative to the optical fiber at least along the longitudinal direction of the optical fiber; the extension degree of the fabric layer in the longitudinal direction is lower than a first threshold value; the fabric layer is sleeved with the outer sleeve layer, and the outer sleeve layer is light-proof and flexible. When the middle section of the optical fiber cable is subjected to sudden external force or is partially tightened, the fabric layer can firstly bear large external force, the optical fiber and the fabric layer slide relatively, and breakage or damage of the optical fiber caused by the fact that most force suddenly acts on the optical fiber can be prevented. Usually, relative sliding between the optical fiber and the fabric layer caused by holding the optical fiber cable by a user is avoided. Even if the optical fiber and the fabric layer cannot slide relatively, when the fabric layer is tightened, the optical fiber cannot be snapped due to the small extensibility of the fabric layer.

Description

Technical Field

[0001] This application relates to the technical field of optical cables, and specifically, to an optical fiber cable for a near-infrared brain functional imaging device and a near-infrared brain functional imaging system having the optical fiber cable. Background Art

[0002] Near-infrared brain functional imaging has become an important research method in psychology and cognitive neuroscience. In near-infrared brain functional imaging (fnirs), a subject wears a headgear provided with a probe assembly, and the probe assembly on the headgear is usually connected to an acquisition module by an optical fiber cable. The optical fiber cable transmits near-infrared light to the subject, and / or receives near-infrared light from the subject and transmits it to the acquisition module.

[0003] During the examination process, sometimes the subject needs to move, or cooperate with the examination of other imaging devices. For example, in a magnetic resonance (MRI) scenario, it is usually necessary to transmit near-infrared light to the head of the subject in the MRI examination room through an optical fiber cable several meters long, and the near-infrared light from the subject's head also needs to be transmitted to the acquisition module using a long optical fiber cable. During the movement process, the optical fiber cable will be repeatedly pulled, and may also sag under the action of gravity and drag on the ground. Therefore, it is easy to pull the optical fiber and cause it to break and be damaged, and the mass density of the optical fiber cable itself will also increase the risk of breakage and damage. On the other hand, researchers and medical experts also need the optical fiber cable to be able to bend freely, even bend freely with a large curvature to meet on-site requirements, which requires more flexible optical fibers and jackets, but the tensile strength of flexible optical fibers and jackets usually cannot meet the actual requirements. Utility Model Content

[0004] To at least partially solve the problems existing in the prior art, an embodiment of this application provides an optical fiber cable for a near-infrared brain functional imaging device, including: an optical fiber; a fabric layer sleeved on the optical fiber, wherein: on at least the middle section of the optical fiber cable, the fabric layer can slide relative to the optical fiber at least along the longitudinal direction of the optical fiber; and the elongation of the fabric layer along the longitudinal direction is lower than a first threshold; and an outer jacket layer sleeved on the fabric layer, the outer jacket layer is light-impermeable and has flexibility.

[0005] Exemplarily, on at least the middle section, the fabric layer and the optical fiber are spaced apart, so that in a plane perpendicular to the longitudinal direction, the optical fiber can move relative to the fabric layer.

[0006] Exemplarily, the fabric layer is woven from synthetic fibers, and the elastic modulus of the synthetic fibers is higher than a second threshold.

[0007] Exemplarily, the synthetic fiber is synthetic silk.

[0008] Exemplarily, the fabric layer is an integrally woven seamless tubular member without stitching lines.

[0009] Exemplarily, the coefficient of friction of the inner circumferential surface of the fabric layer is less than a third threshold value.

[0010] Exemplarily, on at least the middle section, the outer jacket layer is slidable relative to the fabric layer at least along the longitudinal direction of the optical fiber.

[0011] Exemplarily, on at least the middle section, the fabric layer and the outer jacket layer are spaced apart such that the fabric layer is movable relative to the outer jacket layer in a plane perpendicular to the longitudinal direction.

[0012] Exemplarily, the elongation degree of the outer jacket layer along the longitudinal direction is higher than that of the fabric layer along the longitudinal direction.

[0013] Exemplarily, the outer jacket layer has elasticity.

[0014] Exemplarily, a first connection component is connected to the first end of the optical fiber cable, and a second connection component is connected to the second end of the optical fiber cable. At the first end and the second end, the end portions of the optical fiber, the fabric layer, and the outer jacket layer are respectively fixed to the first connection component and the second connection component.

[0015] Exemplarily, each of the tails of the first connection component and the second connection component has a sleeve. The end portion of the optical fiber passes through and is fixed inside the sleeve; the end portion of the fabric layer is sleeved and fixed on the sleeve; and the end portion of the outer jacket layer is sleeved on the end portion of the fabric layer and fixed to the sleeve.

[0016] Exemplarily, a mesh tail is sleeved on the first end of the optical fiber cable, and the mesh tail is fixed to the first connection component.

[0017] Another aspect of the present application provides a near-infrared brain functional imaging system, including: an acquisition module; a probe assembly; and the above-mentioned optical fiber cable, wherein the first end of the optical fiber cable is connected to the acquisition module, and the second end of the optical fiber cable is connected to the probe assembly.

[0018] In summary, when a sudden external force acts on the middle section of the optical fiber cable or it is partially straightened, the fabric layer can first bear a large external force, and the optical fiber and the fabric layer slide relative to each other. Usually, the holding force applied by the user is not sufficient to pinch the optical fiber cable flat, resulting in no relative sliding between the optical fiber and the fabric layer. Setting the optical fiber and the fabric layer to be relatively slidable can prevent most of the force from suddenly acting on the optical fiber, causing the acceleration of the optical fiber to be too large and resulting in fracture or damage. Since the elongation degree of the fabric layer along the longitudinal direction is lower than the first threshold value, when the fabric layer is tightened, the internal optical fiber may not bear a large tensile force or hardly bear a tensile force. Therefore, the optical fiber can be effectively prevented from being pulled broken. In this way, the reliability and service life of the optical fiber cable are significantly improved.

[0019] A series of simplified concepts are introduced in the utility model content, which will be further elaborated in the detailed implementation section. The utility model content section does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0020] The advantages and features of this application will be described in detail below with reference to the accompanying drawings. Brief Description of the Drawings

[0021] The following drawings of this application are hereby part of this application for understanding this application. The embodiments and descriptions of this application are shown in the drawings to explain the principles of this application. In the drawings,

[0022] Figure 1 is a schematic diagram of the application scenario of an optical fiber cable according to an exemplary embodiment of this application;

[0023] Figure 2A is a structural diagram of an optical fiber cable according to an exemplary embodiment of this application;

[0024] Figure 2B is a structural diagram of an optical fiber cable according to another exemplary embodiment of this application;

[0025] Figure 2C is a tail structural diagram of the first connection component of an optical fiber cable according to an exemplary embodiment of this application;

[0026] Figure 3 is a cross-sectional view of an optical fiber cable according to an exemplary embodiment of this application;

[0027] Figure 4A is a cross-sectional view of an optical fiber cable according to another exemplary embodiment of this application;

[0028] [[ID=3,5]] Figure 4B According to Figure 4A is a cross-sectional view of the optical fiber cable when it is bent according to the shown embodiment;

[0029] Figure 5A is a cross-sectional view of an optical fiber cable according to another exemplary embodiment of this application; and

[0030] Figure 5B According to Figure 5A is a cross-sectional view of the optical fiber cable when it is bent according to the shown embodiment.

[0031] Among them, the above-mentioned drawings include the following reference numerals:

[0032] 1. Optical fiber cable; 11. Optical fiber; 12. Fabric layer; 13. Jacket layer; 2. Acquisition module; 3. First connection component; 31. Cable tail; 32. Sleeve; 4, 4'. Second connection component; 5. Head cap. Detailed implementation

[0033] In the following description, a large number of details are provided to enable a thorough understanding of this application. However, those skilled in the art can understand that the following description only exemplarily shows the preferred embodiments of this application, and this application can be implemented without one or more such details. In addition, to avoid confusion with this application, some well-known technical features in the art are not described in detail.

[0034] In order to thoroughly understand the implementation of this application, detailed structures will be presented in the following description. Obviously, the implementation of the embodiments of this application is not limited to the special details familiar to those skilled in the art. The preferred embodiments of this application are described in detail below. However, in addition to these detailed descriptions, this application can also have other embodiments.

[0035] In a near-infrared brain functional imaging system, one end of the optical fiber cable is connected to the acquisition module, and the other end can be connected to the probe assembly on the subject's head cap. Figure 1An exemplary application scenario of the optical fiber cable 1 is shown. One end of the optical fiber cable 1 is connected to the acquisition module 2 through the first connection component 3. Specifically, for example, the first connection component 3 can be an SMA905 connector. The other end of the optical fiber cable 1 is connected to the second connection component 4. The second connection component 4 can be provided with a probe component and fixed on the head cap 5. For clarity and simplicity, only a group formed by including one optical fiber cable 1, one first connection component 3, and one second connection component 4 is shown in the figure. In actual applications, more such groups can be provided. Alternatively, optionally, each optical fiber cable 1 can also include multiple second connection components 4, and each second connection component 4 is provided with its own probe component. In the application scenario of the near-infrared brain functional imaging system in cooperation with other imaging devices, for example, in the scenario of magnetic resonance imaging (MRI), the optical fiber cable 1 may also need to be sent into the scanning room through a waveguide. Since the waveguide is about several tens of centimeters above the ground, the middle section of the optical fiber cable 1 in a suspended state will be pulled under the action of gravity. Moreover, the examination bed usually has a height from the ground, and the middle section of the optical fiber cable 1 may be in a suspended state. Along with the subject entering the scanning room, the optical fiber cable 1 connected to the subject's head cap will also continuously drag on the ground. Of course, the subject can also perform other activities while wearing the head cap. Due to the relatively long length of the optical fiber cable in this scenario and the relatively large weight of the optical fiber cable 1 itself, during the activity, the subject may hold the middle section of the optical fiber cable 1 with both hands and drag the optical fiber cable 1 on the ground. The above-mentioned hanging, pulling, suspended, and dragging states may increase the risk of internal optical fiber breakage and damage. On the other hand, it is necessary for the optical fiber cable 1 to be able to bend freely, even with large curvature free bending to meet the on-site requirements. Therefore, the existing optical fiber cables usually have a flexible outer layer sleeved outside the flexible optical fiber. However, the tensile strength of the flexible optical fiber and the outer layer usually cannot meet the actual requirements.

[0036] The inventor is aware and understands that one of the main reasons for the breakage and damage of optical fibers in optical fiber cables is the tensile force acting on the optical fibers along their longitudinal directions. The optical fibers in currently common optical fiber cables generally include a guiding optical fiber core and a cladding layer covering the guiding optical fiber core. Light is transmitted in the guiding optical fiber core in a total reflection manner. The cladding layer can prevent the guiding optical fiber core from breaking and forms an interface with a large refractive index difference with the guiding optical fiber core. An optical fiber cable may include one or more optical fibers. A protective layer is usually sleeved outside the optical fibers, and the protective layer is used to prevent the optical fibers from being damaged and broken due to abrasion or scratching during use. The inventor's research finds that in existing optical fiber cables, the optical fibers are usually in close contact with the protective layer or the gaps between the optical fibers and the protective layer are filled with fillers. Although this ensures the strength of the optical fiber cable, it will also result in a very large pressure or friction coefficient between the optical fibers and the protective layer, and further make the maximum static friction force between the optical fibers and the protective layer very large. Under the action of the static friction force, the optical fibers and the protective layer are always stationary relative to each other and move synchronously. When the middle section of the optical fiber cable is dragged during daily use or the middle section of the optical fiber cable droops, the external force acting on the protective layer will be directly transmitted to the inner optical fibers, resulting in the optical fibers being easily broken and damaged.

[0037] To address the above problems, the present application provides an optical fiber cable, which is particularly applicable to near-infrared brain functional imaging devices. As Figure 3As shown, the optical fiber cable 1 may include an optical fiber 11, a fabric layer 12, and an outer jacket layer 13. The fabric layer 12 is sleeved on the optical fiber 11 as a protective layer outside the optical fiber 11. On at least the middle section of the optical fiber cable 1, the fabric layer 12 is slidable relative to the optical fiber 11 at least along the longitudinal direction of the optical fiber 11. The longitudinal direction can be considered to be the same as the length direction of the optical fiber 11. It should be noted that in actual use, the optical fiber cable 1 is usually bent, so for different segments of the optical fiber 11, its longitudinal direction may be different. For example, for a vertical optical fiber 11, the longitudinal direction of this segment of the optical fiber 11 is the vertical direction; while for a horizontal optical fiber 11, its longitudinal direction is the horizontal direction. The aforementioned "slidable" means that there is a small coefficient of friction between the fabric layer 12 and the optical fiber 11, and there are no other forces binding the two except for the frictional force. Exemplarily, methods for reducing the frictional force between the fabric layer 12 and the optical fiber 11 include, but are not limited to: using a lubricant, reducing the coefficient of friction of the outer surface of the optical fiber 11 and / or the inner surface of the fabric layer 12, etc. When the optical fiber cable 1 is subjected to an external force, the fabric layer 12 can produce relative sliding with the optical fiber 11. The benefit brought by this is that when a component force along the longitudinal direction suddenly acts on the middle section of the optical fiber cable 1, for example, the user suddenly pulls the middle section of the optical fiber cable 1, or the middle section of the optical fiber cable 1 suddenly drops, since the fabric layer 12 and the optical fiber 11 are slidable at least along the longitudinal direction, the fabric layer 12 and the outer jacket layer 13 can play a buffering role, making the acceleration and / or the moving distance of the optical fiber 11 less than those of the fabric layer 12 and the outer jacket layer 13, thereby protecting the optical fiber 11 and preventing the above-mentioned external force from being directly transmitted to the optical fiber 11.

[0038] In this application, the fabric layer 12 is arranged such that the degree of elongation along the longitudinal direction is lower than a first threshold value. The degree of elongation can be considered as the extent to which an object can be elongated when subjected to a tensile force. When subjected to the same tensile force and with the same material dimensions, the lower the degree of elongation of the material itself, the shorter the length that can be elongated. Thus, during at least one period during or after the movement of the optical fiber cable 1, the fabric layer 12 is in a tensioned state, and the optical fiber 11 preferably presents a slack state within the fabric layer 12, thereby avoiding the optical fiber 11 from being subjected to force. The inventor has found through research that when moving the optical fiber cable 1, the user usually needs to apply pressure to hold the optical fiber cable 1 to increase the friction between the hand and the outer surface of the optical fiber cable 1, thereby preventing the optical fiber cable 1 from slipping in the hand. When the pressure applied by the user is large enough, the friction between the fabric layer 12 and the optical fiber 11 will also increase, which will also cause the optical fiber 11 to move together with the fabric layer 12. Of course, being able to move the inner optical fiber 11 is also what the user desires. Even in the situation described above, after the fabric layer 12 slips relative to the optical fiber 11, it is ultimately desired to be able to move the optical fiber 11. During the process of moving the optical fiber 11 or after the movement is completed, the tensile force applied by the user along the longitudinal direction is preferably borne by the fabric layer 12 or by the fabric layer 12 and the outer jacket layer 13 together. The optical fiber 11 is preferably only carried along by the fabric layer 12 during movement and does not directly bear the tensile force applied by the user. Or when the middle section of the optical fiber cable 1 drops and is in a suspended state, it is desired that more of the gravity of the optical fiber cable 1 is borne by the fabric layer 12 or by the fabric layer 12 and the outer jacket layer 13 together.

[0039] The fact that the fabric layer 12 is at least longitudinally slidable relative to the optical fiber 11 and the fact that the degree of elongation of the fabric layer 12 along the longitudinal direction is lower than the first threshold value complement each other. Specifically, the smaller the first threshold value, the better. Preferably, under the action of an external force, the fabric layer 12 cannot be stretched. Even if the fabric layer 12 can be stretched under the action of an external force, it is desired that when the fabric layer 12 is straightened, the tensile force acting on the optical fiber 11 is reduced to avoid damaging the optical fiber 11. On the other hand, when the tensile force along the longitudinal direction is transmitted from the outside to the inside of the optical fiber cable 1, since the fabric layer 12 is at least longitudinally slidable relative to the optical fiber 11 along the longitudinal direction of the optical fiber 11, the tensile force acting on the fabric layer 12 may not completely act on the optical fiber 11 due to the slippage of the optical fiber 11. Thus, the possibility of the optical fiber 11 being stretched can be reduced to a certain extent, and the risk of the optical fiber 11 breaking can be lowered.

[0040] Since both ends of the optical fiber cable 1 may be fixed to the acquisition module and the probe assembly for being assembled to the headgear, when the headgear is worn on the head of the subject, there is usually a certain distance from the acquisition module. Therefore, during use, the middle section of the optical fiber cable 1 may be held, dropped, suspended, or dragged on the ground by the user. Therefore, the fabric layer 12 may be slidable relative to the optical fiber 11 along the longitudinal direction only on the middle section of the optical fiber cable 1. Of course, the embodiments in which the fabric layer 12 is slidable relative to the optical fiber 11 along the longitudinal direction throughout the optical fiber cable 1 are not excluded in the present application. As described above, the direction of the force applied to the optical fiber cable 1 may not be limited to the longitudinal direction. Therefore, in some embodiments, the fabric layer 12 is also slidable relative to the optical fiber 11 along other directions. Exemplarily, the optical fiber cable 1 may also be locally twisted during use, and the fabric layer 12 being slidable relative to the optical fiber 11 along the circumferential direction can also provide buffering when the optical fiber cable 1 is twisted, avoiding the torsional force and / or the torsional acceleration acting directly on the optical fiber 11.

[0041] The outer jacket layer 13 of the optical fiber cable 1 may be sleeved on the fabric layer 12 as a protective layer outside the fabric layer 12. The outer jacket layer 13 is light-impermeable and flexible. The wear resistance and snag resistance of the fabric layer 12 may be relatively poor. Setting the outer jacket layer 13 can protect the fabric layer 12 and extend its service life. The outer jacket layer 13 may be made of a material with relatively high wear resistance, such as PVC or nylon material. Moreover, PVC and nylon materials are also flexible, can be freely bent, even bent freely with a large curvature to meet on-site requirements, and are light-impermeable, avoiding leakage during the transmission of near-infrared light or interference by external light.

[0042] In addition, the fabric layer 12 may have poor waterproof and dustproof effects, and it is difficult to clean when contaminated by the outside world. The contaminants may also penetrate and corrode the optical fiber 11. Setting the outer jacket layer 13 can prevent the optical fiber 11 and the fabric layer 12 from being contaminated and corroded, and is easy to clean. In the above embodiments using lubricant, the outer jacket layer 13 can prevent the lubricant from leaking and flowing out of the holes of the fabric layer 12, and can ensure that it plays a lubricating role between the optical fiber 11 and the fabric layer 12. In the case where the fabric layer 12 is made of a material with a relatively small friction coefficient, the outer jacket layer 13 may be made of a material with a relatively large friction coefficient, thereby increasing the frictional force between the optical fiber cable 1 and the user's hand and preventing the optical fiber cable 1 from sliding in the user's hand.

[0043] In addition, the fabric layer 12 may be relatively easier to be made soft compared to the outer jacket layer 13. Separating the outer jacket layer 13 from the optical fiber 11 with the fabric layer 12 can also protect the optical fiber 11 from being damaged by the outer jacket layer 13. Moreover, the fabric layer 12 usually has good flexibility, so that it will not affect the requirements for the free bending, even large-curvature bending, of the optical fiber cable 1 during on-site use. Although the flexible optical fiber 11 and the outer jacket layer 13 usually do not meet the actual tensile strength requirements, the fabric layer 12 can have good tensile properties, so it can strengthen the tensile strength of the optical fiber cable 1.

[0044] In summary, when a sudden external force acts on the middle section of the optical fiber cable 1 or it is partially straightened, the fabric layer 12 can first bear a large external force and the optical fiber 11 slides relative to the fabric layer 12. Usually, the holding force applied by the user is not enough to flatten the optical fiber cable 1, resulting in no relative sliding between the optical fiber 11 and the fabric layer 12. Setting the optical fiber 11 and the fabric layer 12 to be relatively slidable can prevent most of the forces from suddenly acting on the optical fiber 11, causing the acceleration of the optical fiber 11 to be too large and resulting in fracture or damage. Since the elongation of the fabric layer 12 in the longitudinal direction is lower than the first threshold, when the fabric layer 12 is tightened, the internal optical fiber 11 may not bear a large tensile force or hardly bear any tensile force, so that the optical fiber 11 can be effectively prevented from being pulled broken. In this way, the reliability and service life of the optical fiber cable 1 are significantly improved.

[0045] As Figure 4A shown, exemplarily, on at least the middle section of the optical fiber cable 1, the fabric layer 12 and the optical fiber 11 can be spaced apart so that in a plane perpendicular to the longitudinal direction, the optical fiber 11 is movable relative to the fabric layer 12. As described above, the user usually holds the middle section of the optical fiber cable 1 and applies a pulling force. Therefore, spacing apart the fabric layer 12 and the optical fiber 11 can effectively reduce the friction between the fabric layer 12 and the optical fiber 11. Of course, this application does not exclude embodiments in which the fabric layer 12 and the optical fiber 11 are spaced apart throughout the entire optical fiber cable 1 along the longitudinal direction. Specifically, there may be a gap D1 between the fabric layer 12 and the optical fiber 11. In an embodiment where only one optical fiber is included in the fabric layer, the gap D1 is determined by the difference between the inner diameter of the fabric layer and the outer diameter of the optical fiber. In the illustrated embodiment, multiple optical fibers 11 are included in the fabric layer 12. Since the cross-section of the optical fiber 11 is usually circular, adjacent optical fibers 11 and the fabric layer 12 can also enclose a void, see Figure 3 G in. Although this void G can cause the fabric layer 12 and the optical fiber 11 to be locally spaced apart, it does not allow the optical fiber 11 to move relative to the fabric layer 12 in a plane perpendicular to the longitudinal direction. Return to see Figure 4A, the gap D1 is determined by the difference between the radius of the circumscribed circle of multiple optical fibers 11 and the inner diameter of the fabric layer 12. Therefore, it allows the optical fibers 11 to move relative to the fabric layer 12 in a plane perpendicular to the longitudinal direction. The gap D1 can be filled with fluids such as air, lubricants, etc. Figure 4A The state shown is an ideal state. In reality, the optical fibers 11 will be supported on the bottom surface of the fabric layer 12 under the action of gravity. Therefore, the gap D1 is not evenly distributed around the entire outer circumference of the optical fibers 11.

[0046] Furthermore, the contact area between the spaced fabric layer 12 and the optical fibers 11 becomes smaller, which can also prevent large-area wear of the cladding of the optical fibers 11 when the fabric layer 12 slips relative to the optical fibers 11. The following describes an example where there is a gap D1 between the fabric layer 12 and the optical fibers 11. In some embodiments, the fabric layer 12 and the outer jacket layer 13 sleeved on the fabric layer 12 can have a certain rigidity. When the fabric layer 12 and the outer jacket layer 13 are subjected to the holding pressure of the user, only a small degree of deformation occurs. There may still be a gap between the deformed fabric layer 12 and the optical fibers 11, and the pressure applied by the user hardly transfers to the optical fibers 11. In some other embodiments, the fabric layer 12 and the outer jacket layer 13 sleeved on the fabric layer 12 have less rigidity. In the case of a large holding pressure, the deformed fabric layer 12 and the optical fibers 11 come into contact with each other, and the fabric layer 12 and the outer jacket layer 13 will transfer a part of the pressure to the optical fibers 11. Since the fabric layer 12 and the outer jacket layer 13 bear a part of the pressure, the pressure received by the optical fibers 11 can be greatly reduced. When the fabric layer 12 and the outer jacket layer 13 slip relative to the optical fibers 11, the frictional force between them and the optical fibers 11 is small. In this way, the fabric layer 12 and the outer jacket layer 13 can play a better buffering role when subjected to an external force.

[0047] The spaced fabric layer 12 can not only slip relative to the optical fibers 11 along the longitudinal direction of the optical fibers 11, but also rotate relative to the optical fibers 11 along the circumferential direction of the optical fibers 11. The middle section of the optical fiber cable 1 may be subjected to a torsional force. The fabric layer 12 and the outer jacket layer 13 can rotate relative to the optical fibers 11 when the optical fiber cable 1 is subjected to a torsional force. If there is still a gap between the fabric layer 12 and the outer jacket layer 13 and the optical fibers 11 after being deformed by the holding pressure of the user or due to free bending, only a part of the torsional force applied to the outer jacket layer 13 may transfer to the optical fibers 11, or it may not transfer to the optical fibers 11. Even if the deformed fabric layer 12 and the optical fibers 11 come into contact with each other, since the structure of the fabric layer 12 itself has borne a part of the torsional force, only a small part of the torsional force can be transferred to the optical fibers 11, greatly reducing the torsional force received by the optical fibers. Thus, the existence of the gap can prevent the torsional force from directly acting on the optical fibers 11, play a buffering role when twisting the optical fiber cable 1, and further prevent the optical fibers 11 from being damaged by torsion and breaking.

[0048] When the optical fiber cable 1 is bent, due to the existence of the gap D1, the optical fiber 11 has more room for movement in the cavity of the fabric layer 12. In the bending section, as Figure 4B shown, the optical fiber 11 can tend to move towards the inner peripheral side of the fabric layer 12, such that: on the inner peripheral side, the gap between the optical fiber 11 and the fabric layer 12 becomes smaller, and even abuts against the fabric layer 12; while on the outer peripheral side, the gap between the optical fiber 11 and the fabric layer 12 becomes larger (see the position marked by the arrow D1), so that the radius of curvature of the optical fiber 11 can be greater than the radius of curvature of the optical fiber cable 1. In other words, the bending of the optical fiber 11 is more gentle. On the one hand, it can prevent the small radius of curvature of the optical fiber 11 from affecting the transmission of infrared light. On the other hand, it can avoid the optical fiber 11 being broken due to excessive bending of the optical fiber cable 1.

[0049] Exemplarily, the fabric layer 12 can be woven from synthetic fibers, and the elastic modulus of the synthetic fibers is higher than the second threshold. The greater the elastic modulus of the synthetic fibers, the smaller the elongation of the synthetic fibers under the action of a unit tensile force, and thus the smaller the elongation of the fabric layer 12 woven from the synthetic fibers. Therefore, the elastic modulus of the synthetic fibers is one of the main factors affecting the elongation of the fabric layer 12. It should be understood that the degree to which the fabric layer 12 can be stretched depends not only on the elastic modulus of its material, but also on the weaving structure. Under the same weaving structure, the greater the elastic modulus of the material used for the fabric layer 12, the less likely the fabric layer 12 is to be stretched when subjected to tension.

[0050] The materials that can be selected include various synthetic fiber fabrics that resist stretching, such as but not limited to polyester fabrics, nylon fabrics, aramid fabrics, carbon fiber fabrics, etc. Preferably, the synthetic fiber can be synthetic silk. The benefits of synthetic silk are: relatively rigid, good moisture absorption effect, not easy to generate static electricity; good fluffiness and air permeability, which can reduce the contact and friction with the optical fiber while fully surrounding the optical fiber; wear-resistant, good anti-pilling property, and there will be no significant pilling phenomenon after long-term use, which can reduce the contact and friction with the optical fiber and ensure that the optical fiber can be freely bent as needed. It is not easy to generate static electricity and has a non-metallic property, which is more suitable for the collaborative multi-modal use scenarios such as nuclear magnetic resonance and transcranial magnetic stimulation. Moreover, the synthetic fiber has a relatively small density, which can also reduce the self-weight of the optical fiber cable 1. The hardness of the synthetic fiber is usually not very large, and it is not easy to cause damage to the cladding of the optical fiber 11 during the friction with the cladding of the optical fiber 11.

[0051] Exemplarily, the fabric layer 12 can be an integrally woven seamless tubular piece without suture lines. Suture lines will make the fabric protrude from the surface of the fabric layer 12, making the surface of the fabric layer 12 uneven, increasing the friction coefficient between the fabric layer 12 and the optical fiber 11, resulting in an increase in the frictional force between the fabric layer 12 and the optical fiber 11. Moreover, the long-term friction of the suture lines on the optical fiber 11 is more likely to cause damage to the cladding of the optical fiber 11. When the suture joint of the fabric layer 12 is subjected to traction, stress concentration will occur, making the fabric layer 12 more likely to break at the suture, resulting in the optical fiber 11 breaking under the traction force. An integrally woven seamless tubular piece without suture lines can be adopted, which is smooth and firm as a whole, and can effectively prevent the optical fiber 11 from breaking and being damaged.

[0052] Optionally, the friction coefficient of the inner circumferential surface of the fabric layer 12 can be less than the third threshold value. Since the maximum static friction force between the optical fiber 11 and the fabric layer 12 is proportional to the friction coefficient of the inner circumferential surface of the fabric layer 12 and the pressure exerted by the fabric layer 12 on the optical fiber 11. The friction coefficient is set to be less than the third threshold value to limit the maximum static friction force between the optical fiber 11 and the fabric layer 12, thereby avoiding damage to the cladding during the friction between the inner circumferential surface of the fabric layer 12 and the cladding of the optical fiber 11. The smaller the friction coefficient of the inner circumferential surface of the fabric layer 12, the better, but there is no absolutely smooth surface. Optionally, the methods for reducing the friction coefficient between the fabric layer 12 and the optical fiber 11 include but are not limited to using a material with a smaller friction coefficient for the fabric layer 12 or using a material with a smaller friction coefficient for the cladding of the optical fiber, etc. On this basis, optionally, a lubricant can also be used to reduce the frictional force between the fabric layer 12 and the optical fiber 11.

[0053] Exemplarily, on at least the middle section of the optical fiber cable 1, the outer jacket 13 is slidable relative to the fabric layer 12 at least along the longitudinal direction of the optical fiber 11. This can reduce the tensile force applied to the fabric layer 12 to a certain extent and lower the risk of the optical fiber 11 breaking. Similar to the fabric layer 12 being slidable relative to the optical fiber 11 at least along the longitudinal direction of the optical fiber 11 as described above, when the middle section of the optical fiber cable 1 is suddenly pulled or suddenly dropped, the outer jacket 13 can first bear a large tensile force. Since the fabric layer 12 and the outer jacket 13 can slide relative to each other, the outer jacket 13 can provide buffering, absorb a part of the tensile force, and then the attenuated tensile force acts on the middle fabric layer 12. Therefore, most of the forces can be prevented from suddenly acting on the fabric layer 12, causing the fabric layer 12 to bear a large tensile force. Thus, the external force applied to the fabric layer 12 can be reduced. Further, the elongation of the fabric layer 12 in the longitudinal direction is low enough and has sufficient tensile resistance, so it can hinder stretching. As a result, the inner optical fiber 11 is basically not subjected to stretching, preventing the optical fiber 11 from breaking or being damaged due to excessive acceleration. From another perspective, since the outer jacket 13 itself has a relatively large mass, when the optical fiber cable 1 is pulled by its own weight, because the fabric layer 12 and the outer jacket 13 can slide relative to each other, the probability that the self-weight of the outer jacket 13 is loaded onto the fabric layer 12 can be reduced. Thus, the fabric layer 12 can be prevented from being subjected to a large tensile force in the longitudinal direction. The outer jacket 13 and the fabric layer 12 are arranged to be relatively slidable. When the optical fiber cable 1 is pulled, the outer jacket 13 can first play a buffering role, reduce the tensile force applied to the fabric layer 12, and further prevent the optical fiber 11 from breaking or being damaged due to excessive tensile force. In some other embodiments, the friction between the outer jacket 13 and the fabric layer 12 can be further reduced. The methods include but are not limited to using lubricants, and the outer surface of the fabric layer 12 and / or the inner surface of the outer jacket 13 having a relatively small coefficient of friction, etc.

[0054] Exemplarily, it can be arranged that only on the middle section of the optical fiber cable 1, the outer jacket 13 is slidable relative to the fabric layer 12 along the longitudinal direction. Of course, the embodiments in which the outer jacket 13 is slidable relative to the fabric layer 12 along the longitudinal direction throughout the optical fiber cable 1 are not excluded in this application. As described above, the direction of the force applied to the optical fiber cable 1 may not be limited to the longitudinal direction. Therefore, in some embodiments, the outer jacket 13 is also slidable relative to the fabric layer 12 along other directions. Exemplarily, during the use of the optical fiber cable 1, it may also be locally twisted. The outer jacket 13 being slidable relative to the fabric layer 12 along the circumferential direction can also provide buffering when the optical fiber cable 1 is twisted, avoiding the torsional force and / or the torsional acceleration directly acting on the optical fiber 11.

[0055] Exemplarily, as Figure 5AAs shown, on at least the middle section of the optical fiber cable 1, the outer jacket layer 13 and the fabric layer 12 can be spaced apart such that in a plane perpendicular to the longitudinal direction, the fabric layer 12 is movable relative to the outer jacket layer 13. Spacing apart the outer jacket layer 13 and the fabric layer 12 can achieve the same technical effect as spacing apart the fabric layer 12 and the optical fiber 11 above, which will not be elaborated here. A gap D2 is formed between the outer jacket layer 13 and the fabric layer 12. This gap D2 can be filled with a fluid, such as air, lubricant, etc. Figure 5A What is shown is an ideal state. In fact, the optical fiber 11 will be supported on the bottom surface of the fabric layer 12 under the action of gravity, and the fabric layer 12 will be supported on the outer jacket layer 13 under the action of gravity. Therefore, the gaps D1 and D2 are not evenly distributed around the entire outer circumference of the optical fiber 11.

[0056] Due to the existence of the gap D2, the fabric layer 12 has a moving space within the outer jacket layer 13. Furthermore, at the bending section, as Figure 5B shown, the optical fiber 11 can have a further increased moving space. Within the bending section, the optical fiber 11 can tend to move towards the inner circumferential side of the fabric layer 12, such that: on the inner circumferential side, the gap between the optical fiber 11 and the fabric layer 12 and the gap between the fabric layer 12 and the outer jacket layer 13 will become smaller, and even the three will be in contact with each other. This can make the curvature radius of the fabric layer 12 larger than that of the outer jacket layer 13. Furthermore, the curvature radius of the optical fiber 11 can be further increased to avoid breakage and damage of the optical fiber 11 when the optical fiber cable 1 is bent. Further, when the optical fiber cable 1 is subjected to torsion, because there is a gap D2 between the outer jacket layer 13 and the fabric layer 12, the frictional force between the two can be reduced. Thus, after the torsion is applied to the outer jacket layer 13, the ratio finally transmitted to the optical fiber 11 will be much smaller. Therefore, the probability of the torsion acting on the optical fiber 11 causing its breakage and damage can be minimized as much as possible.

[0057] Exemplarily, the outer jacket 13 can be elastic. When the optical fiber cable 1 is bent, the outer jacket 13 follows the deformation of the optical fiber cable 1, and its own elastic force can make the optical fiber cable 1 tend to straighten. The larger the bending angle, the greater the elastic potential energy accumulated in the outer jacket 13, and the greater the force required to continue bending the optical fiber cable 1, which can prevent the optical fiber 11 from being overbent. Moreover, as described above, the tensile force applied to the optical fiber cable 1 will first act on the outermost outer jacket 13. The elastic outer jacket 13 can provide better buffering and absorb a larger part of the tensile force, thereby further reducing the tensile force acting on the fabric layer 12. In addition, in the bending section of the optical fiber cable 1, there will be a large deformation on the outer peripheral side of the outer jacket 13. The elasticity of the outer jacket 13 can reduce the amount of deformation during its bending. Specifically, although the outer jacket 13, the fabric layer 12, and the optical fiber 11 are in contact with each other on the inner peripheral side, under the elastic action of the outer jacket 13, the gap between the fabric layer 12 and the outer jacket 13 on the outer peripheral side (see the position marked by the arrow D2) may not increase either. This can avoid the risk of the outer jacket 13 breaking and being damaged.

[0058] Exemplarily, the elongation of the outer jacket 13 in the longitudinal direction is higher than that of the fabric layer 12 in the longitudinal direction. In this way, when the outer jacket 13 is subjected to a tensile force, the outer jacket 13 will elongate, and before reaching the maximum elongation, since the outer jacket 13 is slidable relative to the fabric layer 12, the outer jacket 13 cannot transfer all the tensile force to the fabric layer 12. In this way, even when the outer jacket 13 reaches the maximum elongation, the fabric layer 12 will only bear a small part of the tensile force. By setting the elongation of the outer jacket 13 to be higher than that of the fabric layer 12, the fabric layer 12 reaches the maximum elongation value before the outer jacket 13. At this time, the tensile force is borne by both the fabric layer 12 and the outer jacket 13, preventing the optical fiber cable 1 from being pulled apart.

[0059] Exemplarily, as Figure 2AAs shown, a first connection component 3 may be connected to the first end of the optical fiber cable 1, and a second connection component 4 may be connected to the second end of the optical fiber cable 1. The first connection component 3 is used to connect to the acquisition module 2. The first connection component 3 is, for example, an SMA905 connector or the like. The second connection component 4 is used to connect to the probe component and fix the probe component to the headcap. At the first end and the second end, the end portions of the optical fiber 11, the fabric layer 12, and the outer jacket layer 13 are respectively fixed to the first connection component 3 and the second connection component 4. Taking the first end of the optical fiber cable 1 as an example, the fixing methods include, but are not limited to, using glue to respectively bond the optical fiber 11, the fabric layer 12, and the outer jacket layer 13 to the first connection component 3, or using a clamp to respectively clamp the optical fiber 11, the fabric layer 12, and the outer jacket layer 13 onto the first connection component 3 to achieve fixed connection, or using heat shrinkage to increase the frictional force of the contact surface to achieve fixed connection. The end portions of the optical fiber 11, the fabric layer 12, and the outer jacket layer 13 may contact each other or may not contact each other, and are respectively fixed to the first connection component 3. The end portions of the optical fiber 11, the fabric layer 12, and the outer jacket layer 13 may also contact and be fixed to each other. The second end of the optical fiber cable 1 may be fixed to the second connection component 4 by any of the above-mentioned methods, which will not be elaborated here. In an embodiment not shown, connectors may be connected to both ends of the optical fiber cable 1, and the connector at one end is inserted into the corresponding interface of the probe component on the headcap.

[0060] Figure 2B An embodiment of connecting another second connection component 4' is shown. The second connection components 4 and 4' are respectively used to connect different types of probe components. Figure 2A The shown second connection component 4 is connected to a flat probe component. After being installed on the headcap 5, it will not protrude too much, so that the height between the probe component and the scalp is relatively low, which is suitable for scenarios where it is necessary to reduce the pressure of the probe component on the scalp (such as the MRI scenario), scenarios in combination with treatment equipment (such as the transcranial magnetic scenario), etc. Figure 2B The shown second connection component 4' is connected to a common probe component, and the applicable range of this probe component is wider and the universality is higher.

[0061] Exemplarily, a sleeve may be provided at the tail of each of the first connection component 3 and the second connection component 4. Taking the first connection component 3 as an example, as Figure 2CAs shown, a sleeve 32 may be provided at the tail of the first connection component 3. The end of the optical fiber 11 may be inserted and fixed into the sleeve 32. The sleeve 32 may be annular, and its cross-sectional shape includes but is not limited to circular and rectangular. The sleeve 32 may have an inner peripheral side wall and an outer peripheral side wall. The sleeve 32 may be rigid or flexible, and the material includes but is not limited to metal and rubber. The end of the optical fiber 11 may pass through the cavity inside the sleeve 32. For the SMA905 connector, its sleeve 32 may be a metal sleeve. The end of the optical fiber 11 may be fixed to the inner peripheral side wall of the sleeve 32 by glue bonding. Not shown, the sleeve may be made of heat-shrinkable material, so the sleeve can also be heat-shrunk to firmly sleeve on the optical fiber. The end of the fabric layer 12 may also be sleeved and fixed to the sleeve 32. Specifically, for example, the end of the fabric layer 12 may be sleeved on the outer peripheral side wall of the sleeve 32 and fixed to the sleeve 32 with glue. Or it can be firmly tied to the sleeve 32 with a rubber cord or a metal cord for fixation. The end of the outer jacket layer 13 may be sleeved on the end of the fabric layer 12. Since the end of the fabric layer 12 is fixed to the sleeve 32, therefore, in Figure 2C the illustrated embodiment, the outer jacket layer 13 may be fixed to the fabric layer 12, so as to indirectly fix the outer jacket layer 13 to the sleeve 32. The fixing methods include but are not limited to sewing, glue bonding, etc. In another embodiment, the end of the outer jacket layer 13 may also be directly fixed to the sleeve 32. For example, the fabric layer 12 may be fixed to a part of the sleeve 32, and the outer jacket layer 13 may be fixed to another part of the sleeve 32. The two parts may be arranged along the longitudinal direction or may be staggered along the circumferential direction of the sleeve 32. The fixing methods include but are not limited to glue bonding, heat-shrink process, etc. Thus, the fabric layer 12 and the outer jacket layer 13 may be fixed together with the tail of the first connection component 3, preventing the optical fiber 11 from directly receiving the tensile force when the optical fiber cable 1 is pulled, or preventing the fabric layer 12 and the outer jacket layer 13 from falling off the sleeve 32. For the second connection component 4, any one of the above suitable methods may also be adopted to fix it to the second end of the optical fiber cable 1.

[0062] Exemplarily, the first end of the optical fiber cable 1 may be provided with a mesh tail 31, which is fixed to the first connecting component 3. The junction between the first connecting component 3 and the first end of the optical fiber cable 1 is usually damaged due to frequent activities during pulling and bending. Therefore, a small section of thickened elastic material, namely the mesh tail 31, may be provided on the outer jacket 13 at the junction between the first end of the optical fiber cable 1 and the first connecting component 3. Adding the mesh tail 31 can improve the durability of the optical fiber cable 1 during frequent pulling and bending, and can also disperse the pressure when subjected to force, making the bending arc smoother, thereby reducing the risk of fatigue and breakage of the outer jacket 13. Although the mesh tail 31 design does not change the total amount of force applied to the wire, it can expand the force-bearing area, thereby changing the force-bearing method. Typically, the first end of the fiber optic cable 1 is connected to the acquisition module via the first connecting assembly 3. During use, the fiber optic cable 1 is typically dragged by its middle section, or by the end connected to the probe assembly. Sleeving a tail 31 over the first end of the fiber optic cable 1 prevents the portion of the jacket 13 fixedly connected to the first connecting assembly 3 from becoming thinner or breaking due to fatigue during the dragging process. The tail 31 can be integrally formed with the jacket 13 and fixed to the first connecting assembly 3; it can also be a separate component, mounted on the jacket 13 and then fixed to the first connecting assembly 3; or it can be integrally formed with the first connecting assembly 3 and then mounted on the jacket 13. Tail 31 includes, but is not limited to, an I-shaped tail and a straight tail.

[0063] According to another aspect of the present disclosure, a near-infrared brain function imaging system is also provided. Figure 1 The near-infrared brain imaging system can include any of the aforementioned optical fiber cables 1, an acquisition module 2, and a probe assembly. The first end of the optical fiber cable 1 can be connected to the acquisition module 2, and the second end of the optical fiber cable 1 can be connected to the probe assembly. The near-infrared brain imaging system using the aforementioned optical fiber cable includes at least the aforementioned technical advantages, which will not be further elaborated here.

[0064] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front", "back", "up", "down", "left", "right", "horizontal", "vertical", "vertical", "horizontal", "top", "bottom", etc. are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself.

[0065] For ease of description, regional relative terms such as "above", "over", "on the upper surface", "upper", etc. can be used here to describe the regional positional relationship between one or more components or features shown in the figure and other components or features. It should be understood that regional relative terms not only include the orientation of the components described in the figure but also different orientations during use or operation. For example, if the components in the attached figure are inverted as a whole, the components "above other components or features" or "over other components or features" will include the situation where the components are "below other components or structures" or "under other components or structures". Thus, the exemplary term "above" can include both the orientations of "above" and "below". In addition, these components or features can also be positioned at other different angles (such as rotated 90 degrees or other angles), and this document intends to cover all such situations.

[0066] It should be noted that the terms used here are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used here, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, components, assemblies, and / or combinations thereof.

[0067] It should be noted that the terms "first", "second", etc. in the description, claims, and above-mentioned drawings of the present application are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here.

[0068] The present application has been illustrated by the above embodiments. However, it should be understood that the above embodiments are only for the purpose of exemplification and illustration and are not intended to limit the present application within the scope of the described embodiments. In addition, those skilled in the art can understand that the present application is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present application, and these variations and modifications all fall within the scope claimed by the present application. The protection scope of the present application is defined by the appended claims and their equivalent scope.

Claims

1. An optical fiber cable for a near-infrared brain function imaging device, characterized in that: include: optical fiber; a fabric layer, the fabric layer being sleeved on the optical fiber, wherein: in at least a middle section of the optical fiber cable, the fabric layer is slidable relative to the optical fiber at least along a longitudinal direction of the optical fiber; and an extension of the fabric layer along the longitudinal direction is lower than a first threshold; and The outer layer is sleeved on the fabric layer, and the outer layer is light-proof and flexible.

2. The optical fiber cable according to claim 1, wherein In the at least intermediate section, the fabric layer and the optical fiber are spaced apart such that the optical fiber is movable relative to the fabric layer in a plane perpendicular to the longitudinal direction.

3. The optical fiber cable according to claim 1, wherein The fabric layer is woven from synthetic fibers, and the elastic modulus of the synthetic fibers is higher than a second threshold.

4. The optical fiber cable according to claim 3, wherein The synthetic fiber is synthetic silk.

5. The optical fiber cable according to claim 1, wherein The fabric layer is a seamless tubular member woven in one piece.

6. The optical fiber cable according to claim 1, wherein The friction coefficient of the inner peripheral surface of the fabric layer is less than a third threshold value.

7. The optical fiber cable according to any one of claims 1 to 6, characterized in that: In the at least middle section, the jacket layer is slidable relative to the fabric layer at least along the longitudinal direction of the optical fiber.

8. The optical fiber cable according to claim 7, wherein In the at least intermediate section, the fabric layer and the outer cover layer are spaced apart such that the fabric layer is movable relative to the outer cover layer in a plane perpendicular to the longitudinal direction.

9. The optical fiber cable according to claim 7, wherein: The extension of the outer shell layer in the longitudinal direction is higher than the extension of the fabric layer in the longitudinal direction.

10. The optical fiber cable according to claim 7, wherein The outer shell layer is elastic.

11. The optical fiber cable according to any one of claims 1 to 6, characterized in that: The first end of the optical fiber cable is connected to a first connecting component, and the second end of the optical fiber cable is connected to a second connecting component. At the first end and the second end, ends of the optical fiber, the fabric layer, and the jacket layer are secured to the first connection assembly and the second connection assembly, respectively.

12. The optical fiber cable according to claim 11, wherein The tail portion of each of the first connecting assembly and the second connecting assembly has a sleeve, and the end portion of the optical fiber is passed through and fixed in the sleeve; The end of the fabric layer is sleeved and fixed to the sleeve; and The end of the outer shell layer is sleeved on the end of the fabric layer and fixed to the sleeve.

13. The optical fiber cable according to claim 11, wherein The first end of the optical fiber cable is provided with a mesh tail, and the mesh tail is fixed to the first connecting component.

14. A near-infrared brain function imaging system, characterized in that: include: Acquisition module; Probe assembly; as well as The fiber optic cable according to any one of claims 1 to 13, wherein a first end of the fiber optic cable is connected to the acquisition module, and a second end of the fiber optic cable is connected to the probe assembly.

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