技术领域Technical Field
本说明书涉及医疗器械技术领域，尤其涉及一种光纤探针以及血压监测系统。The present invention relates to the field of medical device technology, and in particular to a fiber optic probe and a blood pressure monitoring system.
背景技术Background Art
人体血液经由两条主要冠状动脉进入心脏，并经由心脏肌肉表面上的一个血管网络，使心脏得到养分。胆固醇、脂肪沉积在动脉中脂质沉积和炎症反应，导致血管管腔狭窄或闭塞，引起心肌缺血和心绞痛等疾病。经过多年的技术的发展，冠状动脉血流储备分数(FFR：Fractional Flow Reserve)作为有创病变功能学评价指标受到了越来越多人的肯定。FFR定义为心外膜狭窄冠状动脉提供给支配区域心肌的最大血流量与同一支冠状动脉正常时提供给心肌的最大血流量的比值，简化定义为心肌最大充血状态下的狭窄远端冠状动脉内平均压(Pd)与冠状动脉口部主动脉平均压(Pa)的比值。Blood enters the heart through two main coronary arteries and passes through a network of blood vessels on the surface of the heart muscle to provide nutrients to the heart. Cholesterol and fat are deposited in the arteries. Lipid deposition and inflammatory reactions lead to stenosis or occlusion of the vascular lumen, causing myocardial ischemia and angina pectoris. After years of technological development, the coronary artery blood flow reserve fraction (FFR) has been recognized by more and more people as an invasive functional evaluation indicator of lesions. FFR is defined as the ratio of the maximum blood flow provided to the myocardium of the innervated area by the epicardial stenotic coronary artery to the maximum blood flow provided to the myocardium by the same coronary artery when it is normal. It is simplified as the ratio of the mean pressure in the stenotic distal coronary artery (Pd) under the state of maximum myocardial hyperemia to the mean pressure in the aorta at the coronary artery orifice (Pa).
现有的血压监测方法主要采用电类传感器进行监测，但是该类产品在使用上存在一些问题和不便。一方面是电类传感器本身易受电磁干扰，采用多点测量时组网困难；另一方面是由于其本身体积过大，进入人体血管内部测量困难，进而导致信号的及时处理与灵敏度受限。Existing blood pressure monitoring methods mainly use electrical sensors for monitoring, but this type of product has some problems and inconveniences in use. On the one hand, electrical sensors are susceptible to electromagnetic interference, making it difficult to network when using multi-point measurements; on the other hand, due to their large size, it is difficult to enter the human blood vessels for measurement, which in turn limits the timely processing of signals and their sensitivity.
光纤压力传感器具有体积小、灵敏度高、抗电磁干扰能力强，以及在某些情况下具有生物相容性和无菌操作的便利性，在医学领域被应用广泛。常见的光纤传感器通常只能测某一点的压力，有时需要多次测量才能实现压力测定，操作十分不便。Fiber optic pressure sensors are widely used in the medical field due to their small size, high sensitivity, strong anti-electromagnetic interference ability, and in some cases, biocompatibility and convenience of aseptic operation. Common fiber optic sensors can usually only measure the pressure at a certain point, and sometimes multiple measurements are required to achieve pressure measurement, which is very inconvenient to operate.
发明内容Summary of the invention
为克服相关技术中存在的问题，本说明书提供了一种光纤探针以及血压监测系统。In order to overcome the problems existing in the related art, this specification provides a fiber optic probe and a blood pressure monitoring system.
根据本说明书实施例的第一方面，提供了一种光纤探针，包括：具有自由端和连接端的套管以及容纳在套管内用于压力测量的n个F-P传感器，n大于等于2，所述F-P传感器包括F-P腔和两个多模光纤，所述F-P腔形成于两个多模光纤之间，每个F-P腔的腔长均不相同，所述多模光纤通过细径光纤连接，所述多模光纤的直径大于细径光纤的直径，所述F-P传感器沿套管自由端向连接端的方向，根据腔长从小到大依次级联在套管内。According to a first aspect of an embodiment of the present specification, there is provided an optical fiber probe, comprising: a sleeve having a free end and a connecting end, and n F-P sensors for pressure measurement contained in the sleeve, wherein n is greater than or equal to 2, the F-P sensor comprising an F-P cavity and two multimode optical fibers, the F-P cavity being formed between the two multimode optical fibers, the cavity length of each F-P cavity being different, the multimode optical fibers being connected by thin-diameter optical fibers, the diameter of the multimode optical fibers being greater than the diameter of the thin-diameter optical fibers, the F-P sensors being cascaded in sequence in the sleeve from small to large according to the cavity length, from the free end of the sleeve to the connecting end.
进一步的，n等于3，3个F-P腔的腔长形成以3为公比的等比数列。Furthermore, n is equal to 3, and the cavity lengths of the three F-P cavities form a geometric progression with 3 as the common ratio.
进一步的，最短F-P腔的腔长为60μm。Furthermore, the shortest F-P cavity length is 60 μm.
进一步的，至少有一F-P传感器设置于套管中心位置，至少有一F-P传感器设置于套管偏心位置。Furthermore, at least one F-P sensor is arranged at the center position of the casing, and at least one F-P sensor is arranged at the eccentric position of the casing.
进一步的，沿着所述套管的轴向，相邻F-P传感器之间的间距相等，间距大于等于1cm，且小于等于3cm。Furthermore, along the axial direction of the sleeve, the spacing between adjacent F-P sensors is equal, and the spacing is greater than or equal to 1 cm and less than or equal to 3 cm.
进一步的，所述F-P传感器在细径光纤外周还设有聚二甲基硅氧烷包层，所述聚二甲基硅氧烷包层充盈所述F-P腔。Furthermore, the F-P sensor is provided with a polydimethylsiloxane cladding on the periphery of the thin-diameter optical fiber, and the polydimethylsiloxane cladding fills the F-P cavity.
进一步的，所述聚二甲基硅氧烷包层直径高于所述多模光纤直径，所述聚二甲基硅氧烷包层轴向的两端均至少部分地包裹所述多模光纤的外周表面。Furthermore, the diameter of the polydimethylsiloxane cladding is greater than the diameter of the multimode optical fiber, and both axial ends of the polydimethylsiloxane cladding at least partially wrap the outer peripheral surface of the multimode optical fiber.
进一步的，还包括与F-P传感器级联的光纤布拉格光栅，所述光纤布拉格光栅的长度大于等于7mm，且小于等于12mm。Furthermore, it also includes a fiber Bragg grating cascaded with the F-P sensor, and the length of the fiber Bragg grating is greater than or equal to 7 mm and less than or equal to 12 mm.
进一步的，F-P传感器沿套管自由端至连接端，分别为第一至第n F-P传感器，所述光纤布拉格光栅靠近套管自由端的一端级联所述第n F-P传感器。Furthermore, the F-P sensors are respectively the first to the nth F-P sensors along the free end to the connection end of the sleeve, and the end of the fiber Bragg grating close to the free end of the sleeve is cascaded to the nth F-P sensor.
根据本说明书实施例的第二方面，提供了一种血压监测系统，包括：环形器、宽带光源、光谱采集模块、计算机设备，以及所述的光纤探针，所述光纤探针通过光纤连接到环形器，所述环形器通过光纤还分别连接了提供光源的宽带光源和接收反射回光谱信息的光谱采集模块，所述光谱采集模块将光谱信息传输至计算机设备，计算机设备对光谱信息进行解调。According to the second aspect of the embodiments of this specification, a blood pressure monitoring system is provided, comprising: a circulator, a broadband light source, a spectrum acquisition module, a computer device, and the fiber optic probe, wherein the fiber optic probe is connected to the circulator via an optical fiber, and the circulator is also connected to a broadband light source providing a light source and a spectrum acquisition module receiving reflected spectral information via optical fibers, respectively, and the spectrum acquisition module transmits the spectral information to the computer device, and the computer device demodulates the spectral information.
本说明书的实施例提供的技术方案可以包括以下有益效果：The technical solutions provided by the embodiments of this specification may have the following beneficial effects:
在探针内部的不同轴向位置上级联设置了多个F-P传感器用于测量血压，使得仅通过一次测量即可获得对不同位置的血压测量，操作简单快速。A plurality of F-P sensors are cascaded at different axial positions inside the probe for measuring blood pressure, so that blood pressure measurements at different positions can be obtained with only one measurement, and the operation is simple and fast.
应当理解的是，以上的一般描述和后文的细节描述仅是示例性和解释性的，并不能限制本说明书。It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present specification.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
图1是本发明一实施例的血压监测系统的结构示意图；FIG1 is a schematic diagram of the structure of a blood pressure monitoring system according to an embodiment of the present invention;
图2是本发明一实施例的光纤探针结构示意图；FIG2 is a schematic diagram of the structure of an optical fiber probe according to an embodiment of the present invention;
图3是图2中F-P传感器的结构图。FIG3 is a structural diagram of the F-P sensor in FIG2 .
附图标记：Reference numerals:
1、宽带光源；2、光纤；3、环形器；4、光纤探针；41、F-P传感器；411、细径光纤；4111、细径光纤纤芯；4112、细径光纤包层；412、多模光纤；4121、多模光纤纤芯；4122、多模光纤包层；413、PDMS包层；42、套管；43、FBG；44、单模光纤；441、单模光纤纤芯；442、单模光纤包层；5、光谱采集模块；6、计算机设备。1. Broadband light source; 2. Optical fiber; 3. Circulator; 4. Optical fiber probe; 41. F-P sensor; 411. Thin-diameter optical fiber; 4111. Thin-diameter optical fiber core; 4112. Thin-diameter optical fiber cladding; 412. Multimode optical fiber; 4121. Multimode optical fiber core; 4122. Multimode optical fiber cladding; 413. PDMS cladding; 42. Sleeve; 43. FBG; 44. Single-mode optical fiber; 441. Single-mode optical fiber core; 442. Single-mode optical fiber cladding; 5. Spectral acquisition module; 6. Computer equipment.
具体实施方式DETAILED DESCRIPTION
图2为本发明一实施例的光纤探针内部结构示意图，图未按实际比例绘制。如图2所示，本发明公开了一种光纤探针4，由于光纤本身体积很小，特别适合用于有创面的血管压力测量。光纤探针4外侧设有套管42，用于支撑和保护内部传感器单元。对于套管42的材料可以选自生物相容性材料，如聚酰亚胺材料。套管42整体为细长型圆管，包括自由端以及与设备相连的连接端，套管42内部从自由端至连接端依次设置n个压力感应单元，n大于等于2，n个压力感应单元级联形成光纤探针4的压力测量部件，用于测量血管内不同位置的血压值。n个压力感应单元均为光纤法布里-珀罗（Fabry-Perot，简称F-P）传感器，即：n个F-P传感器41，如图2虚线方框内所示。n个F-P传感器41从套管42自由端至连接端，依次为第一至第n F-P传感器41，n个F-P传感器41相邻之间通过光纤连接，光纤可以采用成本低、熔接损耗小的单模光纤44。套管42具有血液经过的通道，血液经通道将压力传导到n个F-P传感器41。FIG2 is a schematic diagram of the internal structure of an optical fiber probe according to an embodiment of the present invention, and the figure is not drawn according to the actual scale. As shown in FIG2, the present invention discloses an optical fiber probe 4, which is particularly suitable for measuring blood vessel pressure with a wound surface because the optical fiber itself is very small. A sleeve 42 is provided on the outside of the optical fiber probe 4 to support and protect the internal sensor unit. The material of the sleeve 42 can be selected from a biocompatible material, such as a polyimide material. The sleeve 42 is a slender circular tube as a whole, including a free end and a connecting end connected to the device. The sleeve 42 is sequentially arranged from the free end to the connecting end. n pressure sensing units are cascaded to form a pressure measurement component of the optical fiber probe 4, which is used to measure the blood pressure values at different positions in the blood vessel. The n pressure sensing units are all optical fiber Fabry-Perot (abbreviated as F-P) sensors, that is, n F-P sensors 41, as shown in the dotted box in FIG2. The n F-P sensors 41 are arranged from the free end to the connection end of the sleeve 42, and are sequentially the first to the nth F-P sensors 41. The n F-P sensors 41 are connected to each other by optical fibers, and the optical fibers can be single-mode optical fibers 44 with low cost and small fusion loss. The sleeve 42 has a channel for blood to pass through, and the blood transmits the pressure to the n F-P sensors 41 through the channel.
套管42内部还设有一光纤布拉格光栅（Fiber Bragg Grating，简称FBG），用于温度补偿。FGB 43可设置于套管42中的任意位置，即：可以位于第一F-P传感器41的前端，也可以位于第n F-P传感器后端，亦或是任意两个F-P传感器41之间。如图2实施例所示，作为优选，将FGB 43级联在第n F-P传感器41的后面，即：FGB 43靠近套管42自由端的一端与第nF-P传感器41连接。A fiber Bragg grating (FBG) is also provided inside the sleeve 42 for temperature compensation. The FGB 43 can be arranged at any position in the sleeve 42, i.e., it can be located at the front end of the first F-P sensor 41, or at the rear end of the nth F-P sensor, or between any two F-P sensors 41. As shown in the embodiment of FIG. 2 , preferably, the FGB 43 is cascaded behind the nth F-P sensor 41, i.e., the end of the FGB 43 close to the free end of the sleeve 42 is connected to the nth F-P sensor 41.
n个F-P传感器41以及FBG 43相互之间通过单模光纤44（包括：内部的单模光纤纤芯441以及外部的单模光纤包层442）进行连接。单模光纤44的外直径与多模光纤412的外直径相等。n个F-P传感器41沿套管42的轴向方向以一定的距离分开设置，距离优选为1~3cm。如此设置，既能实现不同位置的血压测量，又能避免光纤探针4整体长度过长，造成使用困难的问题。另外，相邻两个F-P传感器41之间存在的轴向间距优选为相等间距，间距大于等于1cm，且小于等于3cm。由于n个F-P传感器41之间存在间距，使得n个F-P传感器41所测量的血压点位置均不相同，实现了一次可测多个位点的血压值。The n F-P sensors 41 and the FBG 43 are connected to each other through a single-mode optical fiber 44 (including: an internal single-mode optical fiber core 441 and an external single-mode optical fiber cladding 442). The outer diameter of the single-mode optical fiber 44 is equal to the outer diameter of the multi-mode optical fiber 412. The n F-P sensors 41 are separated by a certain distance along the axial direction of the sleeve 42, and the distance is preferably 1~3cm. Such an arrangement can not only realize blood pressure measurement at different positions, but also avoid the problem that the overall length of the optical fiber probe 4 is too long, causing difficulty in use. In addition, the axial spacing between two adjacent F-P sensors 41 is preferably equal spacing, and the spacing is greater than or equal to 1cm and less than or equal to 3cm. Due to the spacing between the n F-P sensors 41, the blood pressure points measured by the n F-P sensors 41 are different, so that the blood pressure values of multiple sites can be measured at one time.
如上所述，可以通过沿套管42轴线方向一定距离分别设置n个F-P传感器41用于测量沿血管长度方向的不同位置的血压值。而为了测量血管截面中不同位置的血压值也可以将F-P传感器41设置在套管42的不同径向位置上，如：套管42的截面中心位置或是偏心位置。如图2所示，在该实施例中，F-P传感器41的数量为3个，其中靠近自由端的第一F-P传感器41设置在套管42的中心位置，第二和第三F-P传感器41则偏心设置。在另外的实施例中，也可以将第一F-P传感器41设置在偏心位置，而第二和第三F-P传感器41设置为中心位置。n个F-P传感器41的径向位置设置可以依需求进行设计。对于偏心位置的F-P传感器41设置可以通过粘接或其他固定方式设置在套管42内表面上。这样设计后，位于套管42中心的F-P传感器41可以测量血管中心位置的血压，而偏心位置的F-P传感器41可以测量血管壁处的血压。As described above, n F-P sensors 41 can be respectively arranged at a certain distance along the axial direction of the sleeve 42 to measure the blood pressure values at different positions along the length direction of the blood vessel. In order to measure the blood pressure values at different positions in the cross section of the blood vessel, the F-P sensor 41 can also be arranged at different radial positions of the sleeve 42, such as: the cross-sectional center position or eccentric position of the sleeve 42. As shown in FIG2, in this embodiment, the number of F-P sensors 41 is 3, wherein the first F-P sensor 41 close to the free end is arranged at the center position of the sleeve 42, and the second and third F-P sensors 41 are arranged eccentrically. In another embodiment, the first F-P sensor 41 can also be arranged at an eccentric position, while the second and third F-P sensors 41 are arranged at the center position. The radial position setting of the n F-P sensors 41 can be designed according to the requirements. The F-P sensor 41 arranged at the eccentric position can be arranged on the inner surface of the sleeve 42 by bonding or other fixing methods. With this design, the F-P sensor 41 located at the center of the sleeve 42 can measure the blood pressure at the center of the blood vessel, while the F-P sensor 41 at the eccentric position can measure the blood pressure at the blood vessel wall.
F-P传感器41是从光学法布里-珀罗干涉仪发展演变而来，它的核心敏感元件是F-P腔，F-P腔可以用来探测压力、温度、振动、加速度等物理参量。一个F-P腔通常是由两个具有一定反射率且严格平行的光学平板构成，这种结构的传感器可贴附于待测物体表面，当受到外界压力或应变等物理量的变化时，会导致传感器F-P腔长的改变，输出的光信号参量也随之改变，通过解调返回的干涉光信号中的F-P腔长信息来实现对监测环境中压力或应变等物理参量变化的监测。The F-P sensor 41 is developed from the optical Fabry-Perot interferometer. Its core sensitive element is the F-P cavity, which can be used to detect physical parameters such as pressure, temperature, vibration, acceleration, etc. An F-P cavity is usually composed of two optical plates with a certain reflectivity and strictly parallel. The sensor of this structure can be attached to the surface of the object to be measured. When the physical quantity such as external pressure or strain changes, it will cause the length of the sensor F-P cavity to change, and the output optical signal parameters will also change accordingly. By demodulating the F-P cavity length information in the returned interference optical signal, the changes in physical parameters such as pressure or strain in the monitoring environment can be monitored.
如图2和图3所示，F-P传感器41包括：F-P腔、两段多模光纤412（包括：内部的多模光纤纤芯4121以及外部的多模光纤包层4122）以及一段细径光纤411（包括：内部的细径光纤纤芯4111以及外部的细径光纤包层4112），其中，多模光纤412分别位于传感器两端，中间形成F-P腔，细径光纤411位于F-P腔中，直径小于多模光纤412直径，用于连接两端的多模光纤412。为了更好地测量血管内某个位置的血压值，F-P腔的腔长方向与套管42的轴向平行，血液流经套管42内部，接触F-P传感器41的多模光纤412，F-P腔受到压力挤压，导致腔长长度发生变化。As shown in FIG. 2 and FIG. 3 , the F-P sensor 41 includes: an F-P cavity, two sections of multimode optical fiber 412 (including: an internal multimode optical fiber core 4121 and an external multimode optical fiber cladding 4122), and a section of thin-diameter optical fiber 411 (including: an internal thin-diameter optical fiber core 4111 and an external thin-diameter optical fiber cladding 4112), wherein the multimode optical fiber 412 is located at both ends of the sensor, forming an F-P cavity in the middle, and the thin-diameter optical fiber 411 is located in the F-P cavity, and its diameter is smaller than that of the multimode optical fiber 412, and is used to connect the multimode optical fibers 412 at both ends. In order to better measure the blood pressure value at a certain position in the blood vessel, the cavity length direction of the F-P cavity is parallel to the axial direction of the cannula 42. Blood flows through the cannula 42 and contacts the multimode optical fiber 412 of the F-P sensor 41. The F-P cavity is squeezed by pressure, resulting in a change in the cavity length.
为了增强F-P传感器41的灵敏性，可在细径光纤411的外周包裹一层聚二甲基硅氧烷（Polydimethylsiloxane，简称PDMS）多孔材料。PDMS是一种有机硅聚合物，与人体组织具有良好的相容性，在生物医疗领域被广泛使用。In order to enhance the sensitivity of the F-P sensor 41, a layer of polydimethylsiloxane (PDMS) porous material may be wrapped around the outer periphery of the thin-diameter optical fiber 411. PDMS is an organic silicon polymer that has good compatibility with human tissue and is widely used in the biomedical field.
如图2所示，压力测定采用n个F-P传感器41进行检测，n取值3。每个F-P传感器41单元包括：F-P腔、细径光纤411、多模光纤412和PDMS包层413，其中，多模光纤412起到耦合器的作用。入射光从单模光纤44输入，经过多模光纤412后，由于多模光纤412的纤芯直径大于细径光纤411的直径，因此一路光被耦合到细径光纤411内传输，另一路光被耦合到PDMS包层413中传输。两束光再经过多模光纤412耦合输出到单模光纤44中。由于PDMS这种多孔材料的特殊性，其对压力的变化非常敏感，当压力发生变化时，PDMS材料的折射率的变化率会比空气的折射率的变化率大很多，从而引起F-P传感器的压力灵敏度大幅度提升，实现了压力增敏的效果。As shown in FIG2 , the pressure measurement is performed using n F-P sensors 41, where n is 3. Each F-P sensor 41 unit includes: an F-P cavity, a thin-diameter optical fiber 411, a multimode optical fiber 412, and a PDMS cladding 413, wherein the multimode optical fiber 412 acts as a coupler. The incident light is input from the single-mode optical fiber 44, and after passing through the multimode optical fiber 412, since the core diameter of the multimode optical fiber 412 is larger than the diameter of the thin-diameter optical fiber 411, one path of light is coupled to the thin-diameter optical fiber 411 for transmission, and the other path of light is coupled to the PDMS cladding 413 for transmission. The two beams of light are then coupled and output to the single-mode optical fiber 44 through the multimode optical fiber 412. Due to the particularity of PDMS, a porous material, it is very sensitive to changes in pressure. When the pressure changes, the rate of change of the refractive index of the PDMS material will be much greater than the rate of change of the refractive index of the air, thereby causing the pressure sensitivity of the F-P sensor to be greatly improved, achieving the effect of pressure sensitization.
为了使PDMS材料能更好地包裹细径光纤411，可以首先将两端已熔接好多模光纤412的细径光纤411放到内径为400μm的毛细管中，然后在毛细管的一端滴加PDMS液体。此时在毛细作用下，PDMS液体将很快充满毛细管，进而使PDMS液体包裹细径光纤411。之后将其放置在加热台上进行固化，固化温度为100℃，时间为1h，最终形成PDMS包层413。In order to make the PDMS material better wrap the thin-diameter optical fiber 411, the thin-diameter optical fiber 411 with multimode optical fibers 412 fused at both ends can be placed in a capillary with an inner diameter of 400μm, and then PDMS liquid is dripped at one end of the capillary. At this time, under the capillary action, the PDMS liquid will quickly fill the capillary, and then the PDMS liquid will wrap the thin-diameter optical fiber 411. Then it is placed on a heating table for curing at a temperature of 100°C for 1 hour, and finally a PDMS cladding 413 is formed.
通过上述方式可将PDMS材料包裹到细径光纤411的外部空间，充盈整个F-P腔，包裹后的PDMS包层413的直径高于两侧的多模光纤412的直径，且PDMS包层413沿轴向的两端均至少部分地包裹多模光纤412的外周表面，使得F-P传感器41的整体性更强，PDMS包层413不易脱落。In the above manner, the PDMS material can be wrapped into the external space of the thin-diameter optical fiber 411 to fill the entire F-P cavity. The diameter of the wrapped PDMS cladding 413 is higher than the diameter of the multi-mode optical fiber 412 on both sides, and both ends of the PDMS cladding 413 along the axial direction at least partially wrap the outer peripheral surface of the multi-mode optical fiber 412, so that the integrity of the F-P sensor 41 is stronger and the PDMS cladding 413 is not easy to fall off.
对于F-P传感器41而言，压力变化会导致F-P腔腔长变化，而腔长变化又会导致干涉光谱的波峰变化，因此通过求解检测波峰，就能获得压力值。参考图1、图2所示，光谱采集模块5采集的信号中包含了n个F-P传感器41的信号，因此，在光谱解调前，首先要对n个F-P传感器41的信号进行信号分离。具体为，首先将光谱采集模块5采集的原始光谱信号进行快速傅里叶变换，获得原始光谱的频谱信息，由于n个F-P传感器41的腔长均不相同，因此可以在频谱图中形成不同的频率分量，然后再使用FIR滤波器将n个F-P传感器41的信号区分开。在这个过程中，如果F-P传感器41的腔长差异性越大，信号分离的效果就越好。但是，受限于探针本身的使用长度，腔长的设置也并不是一味地越大越好。在实际设计过程中，可以根据F-P传感器41的数量以及探针4的长度来进行腔长设计。For the F-P sensor 41, the pressure change will cause the F-P cavity length to change, and the cavity length change will cause the peak of the interference spectrum to change. Therefore, by solving the detection peak, the pressure value can be obtained. Referring to Figures 1 and 2, the signal collected by the spectrum acquisition module 5 contains the signals of n F-P sensors 41. Therefore, before spectrum demodulation, the signals of the n F-P sensors 41 must first be separated. Specifically, the original spectrum signal collected by the spectrum acquisition module 5 is first subjected to a fast Fourier transform to obtain the spectrum information of the original spectrum. Since the cavity lengths of the n F-P sensors 41 are all different, different frequency components can be formed in the spectrum diagram, and then the signals of the n F-P sensors 41 are distinguished using an FIR filter. In this process, the greater the difference in the cavity length of the F-P sensor 41, the better the signal separation effect. However, limited by the use length of the probe itself, the setting of the cavity length is not always the larger the better. In the actual design process, the cavity length can be designed according to the number of F-P sensors 41 and the length of the probe 4.
作为优选，腔长短的尽量置于套管42自由端的前端，即：n个F-P传感器沿套管自由端向连接端的方向，根据腔长从小到大依次级联设置。因为长腔放在前端容易削弱光谱强度，不利于光谱分析。在一实施例中，F-P传感器41数量设置3个，沿套管42的自由端到连接端分别为第一F-P传感器、第二F-P传感器以及第三F-P传感器。为了能够更好地区分3个F-P传感器41的信号可以将3个F-P传感器41的腔长设置为以3为公比的等比数列。具体为，第一F-P传感器的腔长:第二F-P传感器的腔长:第三F-P传感器的腔长等于1:3:9。此时，信号分离效果好，且光纤探针4长度适中。另外，在本实施例中，3个F-P传感器41中最短的腔长设置60μm，此时的光谱信号条纹比对度最佳，包络周期最明显，信号最容易分离。As a preference, the short cavity is placed at the front end of the free end of the sleeve 42 as much as possible, that is, n F-P sensors are cascaded in order from small to large according to the cavity length along the direction from the free end of the sleeve to the connection end. Because the long cavity is placed at the front end, it is easy to weaken the spectral intensity, which is not conducive to spectral analysis. In one embodiment, the number of F-P sensors 41 is set to 3, and the first F-P sensor, the second F-P sensor and the third F-P sensor are respectively from the free end of the sleeve 42 to the connection end. In order to better distinguish the signals of the three F-P sensors 41, the cavity lengths of the three F-P sensors 41 can be set to a geometric progression with 3 as a common ratio. Specifically, the cavity length of the first F-P sensor: the cavity length of the second F-P sensor: the cavity length of the third F-P sensor is equal to 1:3:9. At this time, the signal separation effect is good, and the length of the optical fiber probe 4 is moderate. In addition, in this embodiment, the shortest cavity length of the three F-P sensors 41 is set to 60μm, at which time the spectral signal fringe contrast is the best, the envelope period is the most obvious, and the signal is easiest to separate.
对于F-P传感器41而言，温度和压力的变化都会导致光谱漂移，由于PDMS又是高热光系数材料，如果将这种材料设置在F-P传感器41上又会增加该传感器对温度的敏感性，产生较大的温度串扰。为了减少温度变化对压力探针的精确度影响，在光纤探针4上还设有FBG 43。FBG 43具有对温度和应变非常敏感的特性，FBG 43的中心反射波长会随着周围温度的变化而产生漂移，这种漂移与温度变化成正比。将FBG 43级联到带有F-P传感器41的光纤探针4中，可以利用FBG 43的温度敏感性来监测和补偿温度引起的变化，提高压力测量的精确度。FBG 43的长度可以根据实际应用需要进行定制，长度范围优选为7~12mm，包含端值。For the F-P sensor 41, changes in temperature and pressure will cause spectral drift. Since PDMS is a material with a high thermo-optical coefficient, if this material is set on the F-P sensor 41, the sensor's sensitivity to temperature will increase, resulting in greater temperature crosstalk. In order to reduce the impact of temperature changes on the accuracy of the pressure probe, an FBG 43 is also provided on the optical fiber probe 4. FBG 43 is very sensitive to temperature and strain. The central reflection wavelength of FBG 43 will drift with changes in the surrounding temperature, and this drift is proportional to the temperature change. By cascading FBG 43 to the optical fiber probe 4 with the F-P sensor 41, the temperature sensitivity of FBG 43 can be used to monitor and compensate for changes caused by temperature, thereby improving the accuracy of pressure measurement. The length of FBG 43 can be customized according to actual application needs, and the length range is preferably 7~12mm, including the end value.
如图1所示，本发明公开了一种血压监测系统，用于测量血管中不同位置的血压值。该系统包括光纤探针4，光纤探针4的连接端连接有一光纤2，光纤2的另一端连接有环形器3，环形器3通过另外的两条光纤2还分别连接宽带光源1和光谱采集模块5，其中光谱采集模块5与计算机设备6连接。在系统中光纤2为普通光纤，用于光谱信号传输。监测系统的具体工作流程是，宽带光源1发出的光经过环形器3后传输到光纤探针4中，反射回的干涉光谱经光纤2和环形器3被光谱采集模块5采集，将连续的光谱信号转换成离散的数字电信号，然后在计算机设备6的解调软件上解调得到传感器的腔长信息，进而获得压力信息。解调软件使用全局择优MMSE快速信号解调方法，首先利用快速傅里叶变换方法解调光谱，计算得到F-P传感器41腔长的粗略值，之后，在指定的虚拟腔长模拟范围内以预设步长构建一系列虚拟腔长值及其对应的干涉光谱，计算其与实际光谱的均方误差，获取最小均方差所对应的虚拟腔长值，得到满足要求的最佳腔长值。最后，根据腔长值关联到压力值。As shown in FIG1 , the present invention discloses a blood pressure monitoring system for measuring blood pressure values at different positions in a blood vessel. The system includes an optical fiber probe 4, a connecting end of the optical fiber probe 4 is connected to an optical fiber 2, the other end of the optical fiber 2 is connected to a circulator 3, and the circulator 3 is also connected to a broadband light source 1 and a spectrum acquisition module 5 through two other optical fibers 2, wherein the spectrum acquisition module 5 is connected to a computer device 6. In the system, the optical fiber 2 is an ordinary optical fiber, which is used for spectral signal transmission. The specific working process of the monitoring system is that the light emitted by the broadband light source 1 is transmitted to the optical fiber probe 4 after passing through the circulator 3, and the reflected interference spectrum is collected by the spectrum acquisition module 5 through the optical fiber 2 and the circulator 3, and the continuous spectrum signal is converted into a discrete digital electrical signal, and then demodulated on the demodulation software of the computer device 6 to obtain the cavity length information of the sensor, and then the pressure information is obtained. The demodulation software uses the global optimal MMSE fast signal demodulation method. First, the spectrum is demodulated using the fast Fourier transform method to calculate the rough value of the cavity length of the F-P sensor 41. Then, a series of virtual cavity length values and their corresponding interference spectra are constructed with a preset step size within the specified virtual cavity length simulation range, and the mean square error between them and the actual spectrum is calculated to obtain the virtual cavity length value corresponding to the minimum mean square error, and the optimal cavity length value that meets the requirements is obtained. Finally, the cavity length value is associated with the pressure value.
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| CN202411082298.5ACN118592914B (en) | 2024-08-07 | 2024-08-07 | Optical fiber probe and blood pressure monitoring system |
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| CN202411082298.5ACN118592914B (en) | 2024-08-07 | 2024-08-07 | Optical fiber probe and blood pressure monitoring system |
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