Goodyer P D, Fothergill J C, Jones N B, Hanning C D
Department of Engineering, University of Leicester, U.K.
IEEE Trans Biomed Eng. 1996 Jun;43(6):600-6. doi: 10.1109/10.495279.
The development of an optical fiber transducer for use in biomedical applications has been presented. The design was targeted for use in the upper airways of patients with sleep disorders stemming from partial or total occlusion of the airway. The transducer's preliminary specification was suited for that of upper airway manometry: a resolution of 10 Pa over the range +/- 5 kPa, a single transducer being less than 0.94 mm in diameter. Amplitude modulated optical fiber sensors are susceptible to loss due to bending of the fiber core and cladding. The design of the transducer uses a series of three optical fibers, one emitting and two receiving, the combination of the two receiving optical fibers is used to reduce effects of light loss: a bend radius of 50 mm is typical for the insertion into the naso-pharynx. The transducer transduction element is a silicone gel coated with reflective titanium dioxide, the meniscus deforms under pressure and modulates the intensity of light reflected back into the receiving optical fibers. The main disadvantage of optical fiber pressure transducers is their susceptibility to temperature drift. Temperature in the airway rarely changes more than 17 degrees C. The frequency of breathing and the high thermal mass of the catheter means that temperature drift in this application is not significant, and will cause an insignificant error of 12 Pa. The transducer is inexpensive to produce, and may be deemed disposable: approximately $20 in material costs (using current manufacturing techniques this can be halved). The system has the added advantage of being electrically, magnetically, and chemically passive. The potential for miniaturization is limited only by the mechanical strength of the optical fibers as mechanical problems associated with fragile elastic membranes do not apply.
本文介绍了一种用于生物医学应用的光纤传感器的研发情况。该设计旨在用于因气道部分或完全阻塞而患有睡眠障碍患者的上呼吸道。该传感器的初步规格适用于上呼吸道测压：在±5 kPa范围内分辨率为10 Pa，单个传感器直径小于0.94 mm。振幅调制光纤传感器容易因纤芯和包层弯曲而产生损耗。该传感器的设计使用了三根光纤，一根发射光纤和两根接收光纤，两根接收光纤的组合用于减少光损失的影响：插入鼻咽时典型的弯曲半径为50 mm。传感器的传感元件是涂有反射性二氧化钛的硅胶，弯月面在压力作用下变形并调制反射回接收光纤的光强度。光纤压力传感器的主要缺点是易受温度漂移影响。气道中的温度变化很少超过17摄氏度。呼吸频率和导管的高热容量意味着该应用中的温度漂移不显著，并且只会导致12 Pa的微小误差。该传感器生产成本低廉，可视为一次性使用：材料成本约为20美元（使用当前制造技术可减半）。该系统还具有电、磁和化学无源的额外优势。小型化的潜力仅受光纤机械强度的限制，因为与易碎弹性膜相关的机械问题并不存在。
