A fast processing route of aspheric polydimethylsiloxane lenses array (APLA) and optical characterization for smartphone microscopy

Portable Smartphone‐Based Platform for Real‐Time Particle Detection in Microfluidics

“…[22][23][24][25]27,32] Here, the PDMS lens fabrication was studied using the droplet method on a cylindrical pillar template, combined with the hydrophobic modification of the template and the precuring of liquid PDMS to improve the fabrication precision, magnification ratio range, and to produce different lens shapes. [22][23][24][25]27,32] Here, the PDMS lens fabrication was studied using the droplet method on a cylindrical pillar template, combined with the hydrophobic modification of the template and the precuring of liquid PDMS to improve the fabrication precision, magnification ratio range, and to produce different lens shapes.…”

“…[22][23][24][25] To fabricate this elastomeric lens, the droplet-based fabrication techniques are especially popular as they offer a simple and fast fabrication process. [25,[32][33][34][35][36] In the injection method, the liquid PDMS is injected on top of a substrate and cured with a heating treatment. Currently, there are two popular ways to fabricate the lens with PDMS droplet on a substrate including the upright injection [26][27][28][29][30][31] and hanging method.…”

“…The extent of the magnification depends on the spreading of the liquid PDMS on the substrate, which is influenced by many parameters including the substrate material and temperature, polymer volume, viscosity, and surface tension. [32] Despite this improvement, both methods still suffer from several drawbacks such as limited lens shape and control over the lens structure due to the reliance on gravity. [26] Furthermore, the modification of the needle pinching during the liquid PDMS injection is able to create an aspherical-shaped lens that produces less aberration.…”

“…Currently, there are two popular ways to fabricate the lens with PDMS droplet on a substrate including the upright injection [26][27][28][29][30][31] and hanging method. [25,[32][33][34][35][36] In the injection method, the liquid PDMS is injected on top of a substrate and cured with a heating treatment. The extent of the magnification depends on the spreading of the liquid PDMS on the substrate, which is influenced by many parameters including the substrate material and temperature, polymer volume, viscosity, and surface tension.…”

“…[34] The improvement of the hanging method has been performed by combining in situ heating and hanging which reduce the dropbake cycles. [32] Despite this improvement, both methods still suffer from several drawbacks such as limited lens shape and control over the lens structure due to the reliance on gravity. Here, we developed a new method to precisely control the fabrication of PDMS lens with different size and magnification ratio by changing the surface hydrophobicity of the substrate, the viscosity of the PDMS precursor solution as well as using small pillar template as the substrate.…”