Drop-on-Demand Electrohydrodynamic Jet Printing of Microlens Array on Flexible Substrates

Abstract

The inkjet-printing technique is regarded as an efficient method to fabricate microlens arrays used in digital cameras, medical endoscopes, displays, optical communication, and light source devices. The diameter, height, and aspect ratio of the microlens are the major contributors to these optical properties. Hence, the optical characteristics of the microlens array can vary with the type of inkjet-printing method. In this study, by employing electrohydrodynamic (EHD) jet printing with the drop-on-demand strategy, we fabricated microlenses and microlens arrays using a UV-curable photopolymer liquid on flexible poly(3,4-ethylene­dioxythiophene):polystyrene­sulfonate-coated poly(ethylene terephthalate). By controlling the number of printing drops, which is regarded as an efficient approach to control the dimension of the microlens, lenses with diameters of 11.9 ± 0.2 and 24.4 ± 0.5 μm and aspect ratio ranging from 0.22 to 0.33 were constructed. It was found that the focal length (15.44–26.79 μm), numerical aperture (0.39–0.46), and f-number (1.3–1.1) varied with the number of printing drops. The results demonstrate that the EHD-printed microlenses have a much shorter focal length, higher numerical aperture, and smaller f-number than the previously reported printed lenses. Hence, the EHD-printed microlens can be utilized to produce wide-angle-of-view applications and capture accurate images with insufficient light intensity. In addition, the proposed EHD-printing method may provide a cost-effective and simple route for manufacturing microlens arrays.

Laser-Induced Fabrication of Micro-Optics on Bioresorbable Calcium Phosphate Glass for Implantable Devices

“…As previously shown in Figure 2b, the geometrical profile of the lens was tunable with the laser average power. More importantly, the microlens' shape was tunable between the generally fabricated spherical microlens at a higher average power, and the hyperboloid shape at lower average powers of 10 and 11 W. The ability of hyperboloid microlenses to overcome spherical aberration in order to improve imaging performance is well-known [44,45]. However, the hyperboloid microlens' shape is difficult to achieve through the common microlens fabrication approaches, such as An interesting observation concerns the variation in the microlens' shape with varying laser average power.…”

Fabrication of Large-Area Silicon Spherical Microlens Arrays by Thermal Reflow and ICP Etching

“…Microlens arrays (MLAs) have emerged as an alternative to large aperture optical lenses and are composed of numerous tiny micron-sized lens units arranged in a specific layout. MLAs can provide excellent optical functions, including illumination, collimation, focusing, imaging, and light redistribution, coupled with significantly reduced mass and volume compared to conventional lenses, enabling great application potential across multiple fields, such as imaging systems [1][2][3][4][5], optical communication [6][7][8], and sensors [9,10].…”

Mask-Moving-Lithography-Based High-Precision Surface Fabrication Method for Microlens Arrays

“…Cao Axiu et al conducted research on miniaturized compound eye structures and designed a novel compound eye imaging structure for multi-dimensional information detection [17]. Shi Lifang et al proposed an effective exposure method for aspherical microlens arrays based on an aperiodic moving mask [18][19][20][21]. Dong Xiaochun et al [22] proposed a mask-moving-based fabrication method using contact and proximity lithography equipment, dividing the 3D target structure into numerous strip areas and projecting the microstructures within each strip area to generate 2D mask sub-functions.…”