Microlens array fabricated by a low-cost grayscale lithography maskless system

The design and manufacture of cost-effective miniaturized optics at wafer level, usingadvanced semiconductor-like techniques, enables the production of reduced form-factor cameramodules for optical devices. However, suppressing the Fresnel reflection of wafer-level microlensesis a major challenge. Moth-eye nanostructures not only satisfy the antireflection requirementof microlens arrays, but also overcome the problem of coating fracture. This novel fabricationprocess, based on a precision wafer-level microlens array mold, is designed to meet the demandfor small form factors, high resolution, and cost effectiveness. In this study, three different kinds ofaluminum material, namely 6061-T6 aluminum alloy, high-purity polycrystalline aluminum, and purenanocrystalline aluminum were used to fabricate microlens array molds with uniform nanostructures.Of these three materials, the pure nanocrystalline aluminum microlens array mold exhibited auniform nanostructure and met the optical requirements. This study lays a solid foundation for theindustrial acceptation of novel and functional multiscale-structure wafer-level microlens arrays andprovides a practical method for the low-cost manufacture of large, high-quality wafer-level molds.

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Realization of Three-Dimensional Nanostructure Fabrication by Nanoimprint on Silicon Substrate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.211-212.1105 ◽

2011 ◽

Vol 211-212 ◽

pp. 1105-1109

Author(s):

Xi Qiu Fan

Keyword(s):

Silicon Substrate ◽

Low Cost ◽

Three Dimensional ◽

Microlens Array ◽

Optical Lithography ◽

High Fidelity ◽

Fabrication Method ◽

Nanostructure Fabrication ◽

Large Area ◽

3D Nanostructures

Traditional optical lithography techniques to fabricate three-dimensional (3D) nanostructures are complicated and time consuming. Due to the capability to replicate nanostructures repeatedly in a large area with high resolution and uniformity, nanoimprint (NI) has been recognized as one of the promising approaches to fabricate 3-D nanostructures with high throughput and low cost. This paper introduces a novel 3-D nanostructure fabrication method by nanoimprint on silicon substrate. Nanoscale gratings and microlens array are taken as examples of 3-D nanostructures fabricated by nanoimprint. High fidelity demonstrates the possibility of nanoimprint to fabricate 3-D nanostructures on silicon substrate.

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Design and Fabrication of Wafer-Level Microlens Array with Moth-Eye Antireflective Nanostructures

Nanomaterials ◽

10.3390/nano9050747 ◽

2019 ◽

Vol 9 (5) ◽

pp. 747 ◽

Cited By ~ 4

Author(s):

Shuping Xie ◽

Xinjun Wan ◽

Bo Yang ◽

Wei Zhang ◽

Xiaoxiao Wei ◽

...

Keyword(s):

Nanoimprint Lithography ◽

Production Efficiency ◽

Low Cost ◽

Microlens Array ◽

Wafer Level ◽

Lens Array ◽

Wafer Level Packaging ◽

High Production ◽

Aspherical Lenses ◽

Profile Accuracy

Wafer-level packaging (WLP) based camera module production has attracted widespread industrial interest because it offers high production efficiency and compact modules. However, suppressing the surface Fresnel reflection losses is challenging for wafer-level microlens arrays. Traditional dielectric antireflection (AR) coatings can cause wafer warpage and coating fractures during wafer lens coating and reflow. In this paper, we present the fabrication of a multiscale functional structure-based wafer-level lens array incorporating moth-eye nanostructures for AR effects, hundred-micrometer-level aspherical lenses for camera imaging, and a wafer-level substrate for wafer assembly. The proposed fabrication process includes manufacturing a wafer lens array metal mold using ultraprecise machining, chemically generating a nanopore array layer, and replicating the multiscale wafer lens array using ultraviolet nanoimprint lithography. A 50-mm-diameter wafer lens array is fabricated containing 437 accurate aspherical microlenses with diameters of 1.0 mm; each lens surface possesses nanostructures with an average period of ~120 nm. The microlens quality is sufficient for imaging in terms of profile accuracy and roughness. Compared to lenses without AR nanostructures, the transmittance of the fabricated multiscale lens is increased by ~3% under wavelengths of 400–750 nm. This research provides a foundation for the high-throughput and low-cost industrial application of wafer-level arrays with AR nanostructures.

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Rectangular Microlens Array Having High Sag for Multi Chip LED Packaging

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.1491 ◽

2006 ◽

Vol 326-328 ◽

pp. 1491-1494 ◽

Cited By ~ 2

Author(s):

Won Kyu Jeung ◽

Chang Hyun Lim ◽

Tae Hoon Kim ◽

Seog Moon Choi

Keyword(s):

Mass Production ◽

Light Emitting Diode ◽

Low Cost ◽

Large Diameter ◽

Optical Loss ◽

Microlens Array ◽

Wafer Level ◽

Rectangular Shape ◽

Replication Method ◽

Optical Extraction

A novel rectangular shape microlens array having high sag for solid-state lighting is presented. The rectangular shape of proposed microlens can maximize the fill factor of silicon based light-emitting-diode (LED) packaging and minimize the optical loss through the reduction of unnecessary reflection at the same time. Microlens, which has high sag, over 3 75 μm and large diameter, over 3 mm can enormously enhance output optical extraction eff iciency. Moreover wafer level packaging technology is adopted to improve the aligning accu racy and mass production of LED packaging. This wafer level microlens array can be direc tly fabricated on LED packaging using replication method. It has many advantages in optica l properties, low cost, high aligning accuracy, and mass production.

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Low-cost Fresnel microlens array fabricated by a home-built maskless lithography system

10.1117/12.928819 ◽

2012 ◽

Author(s):

G. A. Cirino ◽

S. A. Lopera ◽

A. N. Montagnoli ◽

L. G. Neto ◽

R. D. Mansano

Keyword(s):

Low Cost ◽

Microlens Array ◽

Maskless Lithography ◽

Lithography System

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Noncontact Microembossing Technology for Fabricating Thermoplastic Optical Polymer Microlens Array Sheets

The Scientific World JOURNAL ◽

10.1155/2014/736562 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Xuefeng Chang ◽

Dan Xie ◽

Xiaohong Ge ◽

Hui Li

Keyword(s):

Mechanical Characteristics ◽

Optical Glass ◽

Low Cost ◽

Microlens Array ◽

Production Costs ◽

Efficient Production ◽

Promising Technique ◽

Element Analysis ◽

Microlens Arrays ◽

Optical Polymer

Thermoplastic optical polymers have replaced traditional optical glass for many applications, due to their superior optical performance, mechanical characteristics, low cost, and efficient production process. This paper investigates noncontact microembossing technology used for producing microlens arrays made out of PMMA (polymethyl methacrylate), PS (polyStyrene), and PC (polycarbonate) from a quartz mold, with microhole arrays. An array of planoconvex microlenses are formed because of surface tension caused by applying pressure to the edge of a hole at a certain glass transition temperature. We studied the principle of noncontact microembossing techniques using finite element analysis, in addition to the thermal and mechanical properties of the three polymers. Then, the independently developed hot-embossing equipment was used to fabricate microlens arrays on PMMA, PS, and PC sheets. This is a promising technique for fabricating diverse thermoplastic optical polymer microlens array sheets, with a simple technological process and low production costs.

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Low-cost microlens array for long-period grating fabrication

Electronics Letters ◽

10.1049/el:19990024 ◽

1999 ◽

Vol 35 (1) ◽

pp. 79 ◽

Cited By ~ 4

Author(s):

S.Y. Liu ◽

H.Y. Tam ◽

M.S. Demokan

Keyword(s):

Low Cost ◽

Microlens Array ◽

Long Period Grating ◽

Grating Fabrication ◽

Long Period

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A Microlens Array with Different Focal Lengths Fabricated by Roll-To-Roll UV Lithography

Polymers and Polymer Composites ◽

10.1177/096739111802600203 ◽

2018 ◽

Vol 26 (2) ◽

pp. 155-159

Author(s):

Huichun Ye ◽

Lianguan Shen ◽

Mujun Li ◽

Likai Li

Keyword(s):

Optical Properties ◽

Low Cost ◽

Microlens Array ◽

Master Mold ◽

Pdms Mold ◽

Microlens Arrays ◽

Array Pattern ◽

Roll To Roll ◽

Ultra Precision ◽

Micro Structures

A simple, highly efficient and low cost roll-to-roll (R2R) UV imprinting lithography facility was achieved for fabricating micro-structures. Firstly, a novel microlens array with focuses distributed on a curved surface was designed and analyzed by an optical software ZEMAX. Then an ultra-precision diamond machine was applied to generate the freeform microlens array features on the master mold, and a belt-type polydimethylsiloxane (PDMS) mold with a microlens array pattern was prepared from the machined master mold. The R2R process was employed to replicate the microlens arrays, followed by an evaluation of their profiles and optical properties. Our experiments demonstrate that the applied method is reliable and efficient for producing the polymeric microlens arrays.

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Realization of Mass Production of Microlens Array by Hot Embossing on Silicon Substrate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.139-141.1562 ◽

2010 ◽

Vol 139-141 ◽

pp. 1562-1565

Author(s):

Xi Qiu Fan

Keyword(s):

High Resolution ◽

High Throughput ◽

Silicon Substrate ◽

Mass Production ◽

Low Cost ◽

Microlens Array ◽

Hot Embossing ◽

High Fidelity ◽

Optical Performance ◽

Large Area

Tradition lithographic techniques to produce micrlens array are complicated and time consuming. Due to the capability to replicate nanostructures repeatedly in a large area with high resolution and uniformity, hot embossing has been recognized as one of the promising approaches to fabricate microlens array with high throughput and low cost. This paper introduces processes to realize fabricating microlens array in mass production by direct hot embossing on silicon substrate. The mold is fabricated by multi-photolithography and etching steps and polymethyl methacrylate (PMMA) is chosen as the resist. Processes include coating, heating, pressing, etc. Fidelity and optical performance of the embossed microlens array were measured. High fidelity and fine optical performance of the embossed microlens array demonstrate the possibility of hot embossing to fabricate microlens array in mass production.

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