In this paper, a novel capacitive sensor for noncontact microdroplet detection has been developed and tested successfully. For an accurate and highly repeatable droplet detection, the sensor makes use of a cross-capacitive structure, which is an extension of the Thompson and Lampard theorem. The sensor consists of four identical copper electrodes with infinitesimally small gaps etched out of double-sided copper-cladded polyimide substrate by screen printing and chemical etching process. The sensor prototype has been tested for different sizes of the droplets as well as the droplets from liquids having different dielectric constants and conductivities. The response characteristics of the presented sensor are very accurate, significant, fast, highly repeatable (±0.13%), and drift free. The achieved characteristics of the presented sensor are suitable for employing it for the noncontact microdroplet detection.

中文翻译：

---

用于非接触式微滴检测的新型交叉电容传感器


本文开发并成功测试了一种用于非接触式微滴检测的新型电容式传感器。为了实现准确且高度可重复的液滴检测，传感器采用了交叉电容结构，这是汤普森和兰帕德定理的延伸。该传感器由四个相同的铜电极组成，这些电极具有无限小的间隙，通过丝网印刷和化学蚀刻工艺从双面覆铜聚酰亚胺基板上蚀刻而成。传感器原型已经针对不同尺寸的液滴以及来自具有不同介电常数和电导率的液体的液滴进行了测试。所提出的传感器的响应特性非常准确、显着、快速、高度可重复（±0.13%）并且无漂移。该传感器所实现的特性适合用于非接触式微滴检测。