基于光蚀刻的内窥光声用PVDF环阵换能器  

Photoetching-based polyvinylidine fluoride annular array transducer for photoacoustic endoscopy

作　　者：周燕[1] 王波[2] 彭宽[1] 金文韬[1] 肖嘉莹[1] 

机构地区：[1]中南大学地球科学与信息物理学院生物医学工程系,湖南长沙410083 [2]湖南大学生物学院,湖南长沙410082

出　　处：《中国医学物理学杂志》2016年第7期717-721,共5页Chinese Journal of Medical Physics

基　　金：国家自然科学基金(31200748;81501517)

摘　　要：目的：目前光声内窥成像中所用的换能器多属于压电陶瓷定焦换能器,这种换能器制作成本昂贵,且景深有限。基于聚偏氟乙烯（PVDF）压电膜制作的环阵换能器可以降低制作成本并通过动态聚焦实现更深的景深。方法：为了提高换能器的灵敏度,本文首次提出基于铝电极PVDF薄膜的光蚀刻方法,将其应用于PVDF环阵超声换能器的制作中。结果：相对于传统的基于PCB板的制作方法,光蚀刻法制作的换能器具有更高灵敏度。该换能器包含3个等宽圆环,总尺寸为5.5 mm。声场测试得其纵向分辨率约为0.5 mm,横向分辨率约为0.5 mm,且在15~45 mm范围内都能很好的聚焦。模拟光声内窥仿体实验验证了其在光声内窥成像中的应用潜力。结论：展示了一种基于覆铝PVDF压电膜制作环阵换能器的新方法。该方法制作的换能器在人体大型器官或腔体（如胃肠道和子宫颈）的光声内窥成像中具有良好的应用前景。Objective Most transducers in photoacoustic endoscopy（PAE） imaging are ceramic and focus- fixed, with expensive customization and limited field depth. The annular array transducer produced by polyvinylidine fluoride（PVDF）piezoelectric film reduces the fabrication cost and allows dynamic focusing for realizing deeper field depth. Methods The photoetching method based on PVDF piezoelectric film of aluminum electrodes was firstly putted forward to improve the sensitivity of transducer. And the photoetching method was applied in the fabrication of PVDF annular array transducers.Results The transducer based on photoetching had higher sensitivity than conventional method based on PCB board. The PVDF annular array transducer contained three independent rings of equal width, with an overall size of 5.5 mm. The sound field test showed the longitudinal resolution was about 0.5 mm, and the transverse resolution was about 0.5 mm, and the transducer had excellent focusing ability in the range from 15 mm to 45 mm. The potential of proposed transducer for PAE imaging had also been proved by the PAE phantom experiment. Conclusion A novel aluminum coating based photoetching method for the fabrication of PVDF annular array transducer is presented in the paper. The potential application of the proposed method includes the PAE imaging for several large human organs and cavities such as the gastrointestinal tract and the cervical canal.

关 键 词：光声内窥镜 聚偏氟乙烯 环阵换能器 光蚀刻 

分 类 号：R318[医药卫生—生物医学工程]