3D inkjet-printing of photo-crosslinkable resins for microlens fabrication

The demand for optical components such as microlenses has been growing at a rapid rate in recent years. While conventional methods for manufacturing these components are well known, they are often time-consuming, detrimental for the environment and unable to keep up with the increasing demand. To overcome these issues, the technique of three-dimensional (3D) inkjet printing has attracted much attention. The aim of this review was to investigate the 3D inkjet printing process as a technique for the fabrication of microlenses and identify the key components and methodologies which can be used to control the properties of the resultant microlenses. 3D Inkjet printing was identified as a viable alternative for the production of microlenses owing to its high flexibility, scalability and efficiency as well as its ability to produce good quality products. Substrate modification was shown as a key method by which the geometric and optical properties of microlenses can be controlled. Organic materials such as acrylates and epoxies, and hybrid materials such as siloxanes were shown to be the most common base materials in photo-crosslinkable inkjet formulations and the effects of incorporation of organic compounds and inorganic nanoparticles on the material refractive index were studied.