Microlenses have become an indispensable optical element in many optical systems. The advancement of technology has led to a wider variety of microlenses fabrication methods, but these methods suffer from, more or less, some limitations. In this article, we review the manufacturing technology of microlenses from the direct and indirect perspectives. First, we present several fabrication methods and their advantages and disadvantages are discussed. Then, we discuss the commonly used materials for fabricating microlenses and the applications of microlenses in various fields. Finally, we point out the prospects for the future development of microlenses and their fabrication methods.

E-jet printing is a micro- and nano-manufacturing technique that utilizes electric field-induced fluid jet printing for achieving better control and resolution than traditional jet printing processes. In addition to high printing resolution, E-jet printing has advantages in some aspects such as wide material applicability, which has been successfully applied in numerous applications that include sensors, transistors, tissue engineering scaffolds, and photonic devices. This article reviews the electrohydrodynamic jet (E-jet) printing technology, which mainly relies on the principle of electrohydrodynamic-induced fluid movement. At the same time, the process of jet formation and droplet deposition is described. The parameters, nozzle design, and ink characteristics of the jet printing process are summarized. Then, a number of concrete applications based on E-jet printing processes are described in this article. Finally, the future development of this technology has been prospected.