Sun Xun, Li Kaixin, Zhang Zifeng, Xiang Linling, Zhou Yihao, Sheng Bin
School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China.
Micromachines (Basel). 2025 Aug 21;16(8):965. doi: 10.3390/mi16080965.
At present, high-resolution and reliable inductive sensors have increasingly emerged as a pivotal component in the advancement of flexible electronic devices. The integration of liquid metal with flexible substrates presents a promising approach for the fabrication of inductive sensors. This paper introduces a novel paperclip-type helical coil inductive sensor, characterized by advancements in both structural design and a simplified manufacturing process. The sensor comprises a fine silicone tube filled with liquid metal, encapsulated within polydimethylsiloxane (PDMS) glue. A significant innovation of this design is its complete elimination of the need for high-precision sacrificial metal molds. This approach bypasses complex processes such as precision mold machining, demolding, and post-mold residue cleaning, thereby significantly streamlining the production work-flow. We optimized the parameters of the paperclip-type helical coil, the aspect ratio, and the number of turns, achieving the maximum sensitivity under limited conditions. Experimental results demonstrate that this sensor is capable of tensile, pressure, and non-contact distance sensing. The linearity of the tensile sensing is exceptional (R2=0.999), with consistent performance observed after 800 tensile cycles. The pressure sensing range extends from 0 to 230 kPa, and the non-contact distance sensing is effective within a range of 10 mm. Furthermore, the sensor exhibits strong performance in monitoring human physiological activities and metal distance detection, demonstrating significant application potential in flexible electronics and wearable devices.
目前，高分辨率且可靠的电感式传感器已日益成为柔性电子设备发展中的关键部件。液态金属与柔性基板的集成是制造电感式传感器的一种很有前景的方法。本文介绍了一种新型回形针式螺旋线圈电感式传感器，其特点是在结构设计和简化制造工艺方面均有进展。该传感器包括一根填充有液态金属的精细硅胶管，封装在聚二甲基硅氧烷（PDMS）胶内。这种设计的一个重大创新是完全无需高精度牺牲金属模具。这种方法绕过了精密模具加工、脱模和模具后残渣清理等复杂工艺，从而显著简化了生产流程。我们优化了回形针式螺旋线圈的参数、长宽比和匝数，在有限条件下实现了最大灵敏度。实验结果表明，该传感器能够进行拉伸、压力和非接触距离传感。拉伸传感的线性度极佳（R2 = 0.999），在800次拉伸循环后性能保持一致。压力传感范围为0至230 kPa，非接触距离传感在10 mm范围内有效。此外，该传感器在监测人体生理活动和金属距离检测方面表现出色，在柔性电子和可穿戴设备中显示出巨大的应用潜力。
