级联光栅硅胶封装的脉象传感器研究

Pulse sensor based on cascade grating using silica gel package

  • 摘要: 提出了一种基于级联光栅的脉象波传感器。相同参数的两个光纤光栅组成级联光栅并植入硅胶腕带中,其中一个光栅作为传感光栅被用于感知脉搏信号,另一个光栅作为匹配光栅被用于解调。由于两个光栅参数完全相同,其反射峰重叠,传感器反射光谱表现为单个反射峰。脉搏搏动产生的应变变化对传感光栅进行调制,导致传感光栅反射峰的中心波长产生偏移,进而导致传感器反射光的强度变化。通过对反射光的强度进行监测,即实现了脉象信息的测量和提取。实验中分别测试了健康男性青年和老年受试者,以及同一个健康男性受试者上午8时和下午8时的脉象信息。结果显示,传感器可有效提取不同受试者的脉象特征点,测试结果符合中医脉象理论。当环境温度变化时,级联光栅中两个光栅的反射峰以相同速率向同一方向偏移,传感器反射光谱的强度不变,因此该传感器不受环境温度影响。此外,该传感器具有结构简单、解调方便、成本较低等优点,在脉象测试中具有一定的应用潜力。

     

    Abstract: A pulse sensor based on cascaded grating is proposed. Cascaded gratings composed of two fiber Bragg gratings with the same parameters are implanted into the silicone wristband. One fiber Bragg grating is used as a sensing grating to sense the pulse signal, and the other grating is used as a matching grating for demodulation. Because the parameters of the two gratings are exactly the same, their reflection peaks overlap, and the reflection spectrum of the sensor shows a single reflection peak. The pulse signal modulates the strain state of the sensing grating under the action of stress, resulting in the shift of the central wavelength of the reflection peak of the sensing grating, which leads to the change of the reflected light intensity of the sensor. By monitoring the reflected light intensity of the sensor, the measurement and extraction of pulse are realized. In the experiment, the pulse of healthy young and old male subjects, and the same healthy male subjects at 8 am/pm are tested. The results show that the sensor can effectively extract the pulse feature points of different subjects, and the test results are in line with the pulse theory of traditional Chinese medicine. When the ambient temperature changes, the reflection peaks of the two gratings shift in the same direction at the same rate, and the reflected light intensity of the sensor remains stable, so the sensor is not affected by the ambient temperature. In addition, the sensor has the advantages of simple structure, convenient demodulation and low cost. There are potential applications in pulse measurement.

     

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