Electrotactile stimulation can be an attractive technology to restore tactile feedback in different application scenarios (e.g., virtual and augmented reality, tele-manipulation). This technology allows designing compact solutions with no mechanical elements that can integrate a high-density matrix of stimulation points. The present study introduced four novel multi-pad finger-electrode designs with different arrangements (two matrix and two circular) and shapes of active pads (producing sensation) and reference pads (ideally, no sensation produced below the pad). The electrodes were used to investigate the subjects’ ability to spatially discriminate active pads within phalanges individually (6–9 pads) as well as across the full finger (18–19 pads). The tests were conducted in 12 subjects and the results showed that all designs led to high success rates when applied to the fingertip (70–81%). When tested on the full finger, the matrix and circular designs were characterized with similar performance (54–57%), and when the phalanges were analyzed individually, the spatial discrimination was best at the fingertip. Additionally, new approaches for faster amplitude calibration were proposed and tested, demonstrating that calibration duration can be reduced by approximately 40% compared to the standard approach of calibrating single pads individually. Finally, discrimination tests of dynamic tactile patterns were conducted using circular and matrix designs on the fingertip and full finger, respectively. The tests showed that the different patterns generated by the two arrangements could be clearly discriminated, especially in the case of full-finger matrix-style patterns. The present study, therefore, provides several important insights that are relevant when delivering tactile feedback to the finger using an electrotactile interface.

中文翻译：

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用于手指电触觉刺激的新型电极设计：比较评估

电触觉刺激可能是一种有吸引力的技术，可以在不同的应用场景（例如虚拟和增强现实、远程操作）中恢复触觉反馈。该技术允许设计紧凑的解决方案，无需机械元件，可以集成高密度刺激点矩阵。本研究介绍了四种新颖的多垫手指电极设计，其具有不同的布置（两个矩阵和两个圆形）以及活动垫（产生感觉）和参考垫（理想情况下，垫下方不产生感觉）的形状。这些电极用于研究受试者在空间上区分指骨内单独的活动垫（6-9 个垫）以及整​​个手指（18-19 个垫）的能力。测试在 12 名受试者中进行，结果表明，所有设计应用于指尖时都取得了很高的成功率 (70-81%)。当在整个手指上进行测试时，矩阵和圆形设计具有相似的性能（54-57%），并且当单独分析指骨时，指尖的空间辨别力最好。此外，还提出并测试了更快幅度校准的新方法，证明与单独校准单个焊盘的标准方法相比，校准时间可以缩短约 40%。最后，分别在指尖和全指上使用圆形和矩阵设计进行动态触觉图案的辨别测试。测试表明，可以清楚地区分两种排列生成的不同图案，特别是在全指矩阵式图案的情况下。因此，本研究提供了一些与使用电触觉界面向手指传递触觉反馈相关的重要见解。