Design and fabrication of a large-aperture electrowetting liquid zoom system

In this paper, a continuous zoom system based on large-aperture electrowetting liquid lenses is designed and fabricated. The inner diameter of the electrowetting lens is up to 20 mm, which can tune stably from a focal length of −328.49mm to −∞ with applied voltages of 0 to 115 V. The zoom system mainly consists of two large-aperture electrowetting liquid lenses and a glass lens, getting continuous zoom images by adjusting the voltages applied to the two liquid lenses without any mechanical movement, ensuring a more compact structure than conventional zoom systems. The theoretical formulas of the zoom ratio and image plane stability condition for this optical system are systematically derived based on the matrix optics, laying the foundation for guiding system regulation and finding methods to improve zoom ratio, and corresponding influence factors on the zoom ratio are verified by experiments. The system zoom ratio can reach 1.52 at a fixed working distance, close to the theoretical derivation result. The system is expected to be used for imaging in a variety of scenarios, such as special photography, dynamic measurement, etc.